![Introduction 5
an extent about psychology, too). As such, appendicitis is palpably ‘bad,’ an ‘evil’
that demands cure or amelioration. However, the equivalent situation does not
hold in communication science. Many people, including communication research-
ers and teachers, may believe that the communication phenomenon of pornogra-
phy is ‘bad’; but there is certainly no consensus on this issue. For communication
science, it is still difficult to arrive at a foolproof definition of pornography. In the
second place, a definitive account of the ‘effects’ – if any – of pornography on all
people, of all different kinds, is a long way away. The object of communication
science is therefore underdetermined and inescapably so. Furthermore, there are
numerous reasons for this. If we take an example from the foundation of medicine,
we know that Hippocrates (1983 [c. 430–330 bc]: 185) advanced medical science
by observing that a symptom exists as such when it is found to be identical in
Delos, Scythia and in Libya. Where the object of communications is concerned,
the opposite is the case: the object will be subject to sometimes significantly differ-
ent degrees of difference according to geography and context. This is the reason,
too, that the study of communication can never be organized according to the
implementation of just one method, typically either adopted from a social science
template or from a humanities one. The frequently extreme variation and richness
of the cultural context in which communication takes place dictates that a diverse
set of methods is crucial to the task of attempting to unravel the nature of commu-
nication in different places and contexts. This is not to say that the object of com-
munication science can be simply summed up as ‘cultural signs’ or ‘signs in con-
text.’ Whilst these are dominant in communication science, there are also
endeavours which serve to illustrate the illusory basis of the nature/culture divide.
One of these is the investigation of communication disorders (Rieber 1981; Damico
et al. 2010); another is biosemiotics (see Cobley, Chapter 12).
Unlike medicine, then, it is difficult to say what communication science is not
about. Communication is sufficiently general that it suffuses other disciplines or
objects. This is so to the extent that it is even easy to find examples in which the
interaction of cells or other organic entities are said to be involved in ‘communica-
tion.’ Often, this term is used in a self-consciously metaphorical way. Yet, on the
same level, it would be strange to encounter a sociology of neurons or the philoso-
phy of metals. Communication science, of course, is not alone in having a diverse
profusion of objects. Because of their focus on objects which change according to
issues of sociality, geography, time, and context, both communication and sociol-
ogy, despite their many differences, are fragmented. Communication science and
psychology, again with many differences, have a slightly different experience of
fragmentation, with the latter discipline being fragmented in some areas and uni-
fied in others. There is really no single object of communication science. However,
if one were to posit one possible object it might be the human communicative act –
often conceived as “someone communicates something to someone else”. This, of
course, is the thread of one of the most fundamental models of communication](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-19-320.jpg)
![Introduction 15
Donsbach, Wolfgang. 2006. The identity of communication research. Journal of Communication
56. 437–448
Donsbach, Wolfgang (ed.). 2008. International encyclopedia of communication. 12 vols. Malden,
MA: Blackwell.
Hippocrates. 1983. [c. 430–330 bc]. Hippocratic writings. Chadwick, J. and Mann, W. N. (trans.).
Harmondsworth: Penguin.
Jaccard, James & Jacob Jacoby. 2010. Theory construction and model-building skills. New York and
London: The Guilford Press
Kaplan, Abraham. 1964. The conduct of inquiry. Methodology for behavioral science.
New Brunswick and London: Transaction.
Kerlinger, Fred N. & H. B. Lee. 2000. Foundations of behavioral research. Wadsworth: Thomson
Learning.
Lasswell, Harold D. 1948. The structure and function of communication in society. In: Lymon
Bryson (ed.), The communication of ideas, 37–51. New York: Institute for Religious and Social
Studies.
Livingstone, Sonia. 2009. On the mediation of everything. ICA Presidential address 2008. Journal
of Communication 59 (1). 1–18.
Lyotard, Jean. 1984. The postmodern condition: A report on knowledge. Bennington Geoffrey and
Massumi, Brian (trans.). Minneapolis, MN: University of Minnesota Press.
Mumby, Dennis K. 1997. Modernism, postmodernism, and communication studies: A rereading of
an ongoing debate. Communication Theory 7 (1). 1–28.
Peters, John Durham. 1996. Sharing of thoughts or recognizing otherness? Reply to Logue and
Miller. Critical Studies in Mass Communication 13 (4). 373–380.
Peters, John Durham. 2008. Communication: history of the idea. In: Wolfgang Donsbach (ed.)
International encyclopedia of communication. Vol. II, 689–693. Malden, MA: Blackwell.
Rosengren, Karl Erik. 2000. Communication: an introduction. London and Thousand Oaks: Sage.
Rieber, Robert W. 1981. Communication disorders. Dordrecht: Springer.
Schement, Jorge Reina. 1993. Communication and information. In: Jorge R. Schement and Brent D.
Ruben (eds.), Between communication and information. Information and behaviour, Vol. 4,
3–34. New York: Transaction.](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-29-320.jpg)
![22 William F. Eadie and Robin Goret
conveyed to the personal level from the public level, where lies the locus of social
control, including control over language itself (Barthes 2000).
In fact, according to Barthes, linguistic signs with a forceful social meaning
are not necessarily ‘clear’ but are rather ambiguous or deceptive in some way.
Thus linguistic signs, as attributes of culture, lend themselves to ‘myth’, a ‘lan-
guage’ devoted to the “decorative display of the what-goes-without-saying” which
prevents the imposing “at the outset [of] a full meaning which it is impossible to
distort” (Barthes 2000: 11, 132). Language may be unclear in a variety of ways,
either because it is poetic or because it works by analogy. The key idea, for Barthes,
is that language “lends itself to multiple contingencies” (132). Semiologists engage
in this interpretive act, and it is up to the reader of myths to reveal their necessary
function. That is because “in a language, the sign is arbitrary: nothing compels
the acoustic image tree ‘naturally’ to mean the concept tree” (126). Instead, Barthes
posited, there is a motivation for the sign to mean whatever it means from the
habits and the traditions of the community of language users in which the word
appears.
Where language use is intent on signifying a cultural meaning there is
undoubtedly intent to affect the psychological experience of that meaning (Barthes
2000). Motivation, Barthes argued, is essential “to the very duplicity of myth: myth
plays on the analogy between meaning and form, there is no myth without moti-
vated form” (126). Barthes cited the innumerable images that the media use to
convey a social message, to imply, without directly pronouncing, the superiority
of a Eurocentric and bourgeois worldview. The communicated image conforms to
what Barthes termed the “very principle of myth: it transforms history into
nature …[and] is not read as a motive, but as a reason” (129). In due course, he
argued, values get conveyed with the authority of facts, all in the service of social
control. Only when the receivers that would be recognized as decoders of language
themselves effect language change is social control likely to shift. Thus, the “bour-
geoisie hides the fact that it is the bourgeoisie and thereby produces myth; revolu-
tion announces itself openly as revolution and thereby abolishes myth” (146). (See
also Chapter 12, Cobley.)
Somewhat in contrast to Barthes, interest in language use by Vygotsky (1971:
originally published in 1934) and Ayer (1936) drew upon logical positivism and
empiricism as a means of explaining the relationship of language to reality. Vygot-
sky saw language development as a function of experience with one’s environment,
using language to associate objects with thoughts and feelings. Ayer proposed the
use of language as a means of verifying the logic of one’s environment. Language
in itself is not verifiable, but it can be used to understand what may be verified
empirically.
A desire for empirical verification also pervaded the development of General
Semantics, which started out as a theory of language use and became more a
philosophy of communication than anything else. Begun by a Polish engineer](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-36-320.jpg)
![Theories and models of communication: foundations and heritage 23
named Alfred Korzybski (1933) and popularized in the U. S. by S. I. Hayakawa
(1941), General Semantics began with the observation that language was not a
logical system and ended by advocating for a series of devices designed to make
communication based on language that was concrete, as opposed to abstract. Gen-
eral Semanticists envisioned a communication system with as little ambiguity as
possible so as to promote understanding and thereby reduce conflict, particularly
conflict between nations. The proposed system was based on a set of tools that
would continually remind language users to aim for the lowest possible level of
abstraction in both speech and writing.
Peirce’s (cf. 1878) work on the philosophical movement known as pragmatism
influenced a number of U. S. scholars interested in language use. Among those
were John Dewey, whose book, How We Think (1910), became the basis for teaching
generations of students the basics of collective decision-making, and George Her-
bert Mead, whose book, Mind, Self, and Society (1934, a posthumous rendering
of his theory, based on lecture notes and working papers) became a basis for
understanding how individuals interact with society through the use of signs and
symbols. Mead and Dewey were colleagues at the University of Chicago for a time,
and their interactions with each other and with colleagues were instrumental in
developing the perspective that became known as the Chicago School of Sociology.
Communication scholars eventually pursued with gusto Mead’s ideas about
what was eventually called symbolic interactionism (Blumer 1969). Symbolic inter-
actionism held that individual behavior was a function of the repertoire of roles
available to an individual, as well as how that person diagnosed what role might be
appropriate for a particular situation. Hart and Burks’s (1972) concept of rhetorical
sensitivity provided an early example of the influence of symbolic interactionism
in communication study, as these authors combined rhetorical message-generation
principles with symbolic interaction’s emphasis on role-taking and adaptation.
Eventually, symbolic interactionism gave way to social construction, as communi-
cation scholars adapted the work of psychologist Kenneth Gergen (1992, 1999) for
use in communication research. Social construction derived from the work of Ber-
ger and Luckmann (1966), who argued that communication is dependent on inter-
subjective meaning that operates at a societal level but is subject to re-negotiation
within individual and group relationships.
Kenneth Burke was a literary theorist whose ideas would prove to be highly
influential in understanding of the rhetorical aspects of language use. Burke
described language as a tool used by people to communicate and rationalize at a
far deeper level than could be done by words themselves. Burke focused on the
symbols people created to name things in his understanding of language. Accord-
ing to Holland (1955) when rhetoricians analyzed speeches, they tended to look at
three aspects – what was said, why it was said and how it was said. Burke however,
would argue that Holland’s formulation did not go far enough and that a primary
goal of criticism was to use “all [language instruments] that there is to use” (Burke,](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-37-320.jpg)
![32 William F. Eadie and Robin Goret
Craig (1999) worried that scholars adhering to each of his traditions were suffi-
ciently different from each other that they potentially could not engage in dialogue
about what issues were important to communication as a discipline. Disciplinary
dialogue, Craig argued, is essential to growth, development, and ultimately to dis-
ciplinary health. While we have defined the major intellectual strands of communi-
cation in a slightly different manner than did Craig, we do not have the same
worries. There may be no such thing as COMMUNICATION THEORY, but there may
be many communication theories, each proceeding from a different understanding
of communication phenomena and each contributing to scholarship proceeding
from that understanding. There may be quarrels about which of these understand-
ings is “correct” (or, more likely, which might be considered “incorrect” or “inad-
equate”), but ultimately we find commonality through appreciating the variety of
different approaches and the scholarship they have produced. “Communication”
may turn out to be the wrong term to define what we are studying, but for the
moment it is good enough.
Further reading
Anderson, James A. & Geoffrey Baym. 2004. Philosophies and philosophic issues in
communication, 1994–2004. Journal of Communication 54. 589–615. doi:10.1093/joc/
54.4.589
Craig, Robert T. 1999. Communication theory as a field. Communication Theory 9. 117–161.
doi:10.1111/j.1468–2885.1999.tb00355.x
Eadie, William F. 2011. Stories we tell: Fragmentation and convergence in communication
disciplinary history. The Review of Communication 11. 161–176.
Peters, John Durham. 1999. Speaking into the air: A history of the idea of communication.
Chicago, London: University of Chicago Press
Rogers, Everett M. 1994. A history of communication study: A biographical approach. New York:
Free Press.
References
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Bandura, A. 1986. Social foundations of thought and action: A social cognitive theory. Englewood
Cliffs, NJ: Prentice-Hall.
Barthes, R. 2000. Mythologies, Lavers, A. (trans.). New York: Hill and Wang. [Originally published
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![CHAPTER VIII.
THE CHEMICAL CONSTITUENTS OF SKIN.
The chemistry of the various constituents of skin is still very
imperfectly understood, but Beilstein, in his great handbook of organic
chemistry, places gelatin, albumens and keratins in the “aromatic”
series, and implies therefore that they contain the “benzene” ring. It is
at least certain that all are very complex.
The epidermis structures belong to the class of keratins, which are
closely related to coagulated albumin; while the white fibres of the
corium (or true skin) are either identical with gelatin, or only differ from
it in their molecular condition or degree of hydration. This gelatinous
tissue constitutes the bulk of the corium, but it also contains albumen
as a constituent of the lymph and blood which supply its nourishment,
keratins in the epithelial structures of the blood and lymph vessels, and
“yellow fibres,” which are perhaps allied to the keratins, but which
cannot well be isolated for analysis.
The white connective tissue of the corium is converted into gelatin
(glutin) by boiling with water. Owing to the impossibility of obtaining
unaltered hide-fibre free from the other constituents, and still more to
that of deciding to what point it should be dried to remove uncombined
water, it is impossible to prove by analysis whether its composition is
identical with that of glutin; but as the white fibre constitutes by far the
largest part of the corium, and the other constituents do not differ
largely from it in their percentage composition, an analysis of carefully
purified corium is practically identical with that of the actual fibre. The
following analyses of hide and gelatin are therefore of interest.
The analyses of Von Schroeder and Paessler[22] are of special
importance as being the average of a large number of separate
determinations. Their nitrogen determinations are by Kjeldahl’s method.
Small amounts of ash and traces of sulphur are neglected, and
probably included in the O, which is obtained by difference.](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-56-320.jpg)
![[22] Ding. Polyt. Journ., 1893, cclxxxvii. pp. 258, 283, 300.
Analyses of Purified Corium.
Analyst. Material. C H N O S
Stohmann and Langbein .. 49·9 5·8 18·0 26·0 0·3
Müntz Ox-hide 51·8 6·7 18·3 23·2 ..
Von Schroeder and
Paessler
Ox, calf, horse, camel, pig,
rhinoceros
50·2 6·4 17·8 25·4 ..
„ Goat and deer 50·3 6·4 17·4 25·9 ..
„ Sheep and dog 50·2 6·5 17·0 26·3 ..
„ Cat 51·1 6·5 17·1 25·3 ..
Analyses of Gelatin (free from Ash).
Analyst. C H N O
Von Schroeder and Paessler 51·2 6·5 18·1 24·2
Mulder 50·1 6·6 18·3 25·0
Fremy 50·0 6·5 17·5 26·0
Schützenberger 50·0 6·7 18·3 25·0
Chittenden and Solly[23] 49·4 6·8 18·0 25·1
[23] Contained also 0·7 sulphur. Journ. Physiol., xii. p. 23.
It will be noted that the above analyses of skin differ more widely
among themselves than their average does from that of the gelatin
analyses, though on the whole the nitrogen is somewhat higher in the
latter. The molecular weight of gelatin must be very high,[24] and any
empirical formula founded on ultimate analysis therefore quite
hypothetical. Bleunard,[25] Schützenberger and Bourgois,[26] and
Hofmeister agree on the formula C76H124N24O29, which leads to the
following percentage composition:—
per cent.
C76 = 912 = 49·7
H124 = 124 = 6·8
N24 = 336 = 18·3
O29 = 464 = 25·2
1836 100·0
[24] Paal (Berichte D. Ch. Ges., xxv. (1892) pp. 1202-36, and Ch. Soc.
Abst., 1892, pp. 895-7) calculates a molecular weight of about 900 from](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-57-320.jpg)
![physical (freezing, boiling point) methods.
[25] Annales de Chimie [5] xxvi. p. 18.
[26] Compt. Rend., lxxxii. pp. 262-4.
The addition of a molecule of water would make a difference in the
percentage composition indicated by these formulæ which would be
less than their probable experimental error, and the change may
therefore be one of hydration.
Gelatin certainly contains both carboxyl and amido-groups, and is
capable of combining with both acids and alkalies (see p. 84).
Reimer[27] obtained what he supposed to be pure unaltered fibre-
substance by digestion of purified hide with 1⁄2 per cent. acetic acid for
many days and subsequent neutralisation. His analysis showed C =
48·45 per cent., H = 6·66 per cent., N = 18·45 per cent., O = 26·44
per cent., thus deviating considerably from direct analysis of unaltered
skin. It is obvious that little weight can be placed on this result,
Reimer’s precipitate being probably a mere decomposition product.
[27] Ding. Polyt., ccv. p. 164.
Hofmeister[28] notes that on heating gelatin it loses water and forms
an anhydride which he considers identical with collagen or hide-fibre.
When gelatin is dried at a temperature of 130° C. it becomes incapable
of solution in water, even at boiling temperature, and can only be
dissolved by heating under pressure. It is certain that collagen (hide-
fibre, ossein) is less easily soluble in hot water than ordinary gelatin.
[28] Bied. Centr., 1880, p. 772.
So far as our present knowledge goes, we may regard hide-fibre as
merely an organised and perhaps dehydrated gelatin.
Gelatin or glutin (not to be confounded with the gluten of cereals),
when pure and dry is a colourless, transparent solid of horny toughness
and of sp. gr. 1·3. It begins to melt about 140° C., at the same time
undergoing decomposition. It is insoluble in hydrocarbons, in ether, or
in strong alcohol. In cold water it swells to a transparent jelly,
absorbing several times its weight of water, but does not dissolve. In
hot water it is soluble, but a solution containing even 1 per cent. of
good gelatin sets to a weak jelly on cooling. Gelatin jellies melt at
temperatures which vary considerably with the quality or freedom from
degradation products, but which within pretty wide limits (5-10 per](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-58-320.jpg)
![cent.) are little affected by the concentration. A 10 per cent. solution of
best hard gelatin melts about 38° C., while low glue may fail to set at
15° C. A useful technical test for the setting power of gelatin, based on
this fact, consists in placing an angular fragment of the jelly in a small
tube attached to a thermometer, and stirring in a beaker of water,
which is slowly heated till the jelly melts, when the temperature is
noted. The exact point is perhaps more easily seen if the tube is drawn
to a conical point. The jelly may also be allowed to set in capillary tubes
open at the bottom, and the moment noted when water rises into the
tube. The temperature of fusion is raised by the addition of
formaldehyde, salts of chromium, alumina and ferric salts, which
produce a tanning effect, and in a less degree by sulphates, tartrates,
acetates, some other salts, and diminished by iodides, bromides,
chlorides and nitrates.[29] Solutions of gelatin too weak or too warm to
gelatinise possess considerable viscosity. Gelatin may therefore be
estimated, in the absence of other viscous matters, by the viscosimeter,
an instrument which measures the time taken by a liquid in flowing
through a capillary tube.[30] The firmness of a jelly, which is often
important for commercial purposes, is frequently measured by
Lipowitz’s method, in which a slightly convex disc, conveniently of
exactly 1 cm. diameter, and cemented to the bottom of a thistle-head
funnel tube, is loaded gradually with mercury till it sinks in the jelly. The
jelly (5 or 10 per cent.) should be allowed to set some hours before the
test is made.
[29] See Pascheles, ‘Versuche über Quellung,’ Archiv für ges. Path., Bd. 71.
[30] See Prollius, Ding. Polyt. Journ., ccxlix. p. 425, who employs a 1 per
cent. solution; also Stützer, Zeit. Ann. Ch., xxxi. pp. 501-15.
Solutions of gelatin from skin and bone are powerfully lævorotatory
to polarised light. At 30° C. (A)D = -130°, but temperature and the
reaction of the solution have much influence on the value found.
Gelatin is precipitated from aqueous solution by the addition of
strong alcohol and concentrated solutions of ammonium sulphate and
some other salts. Many other colloid bodies such as dextrin and gums
behave similarly. In the absence of these substances, precipitation by
alcohol may be utilised for the technical analysis of gelatins and glues,
printers’ roller compositions and gelatin confectionery. 25 c.c. of the
gelatinous solution, which is preferably of about 10 per cent., is placed](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-59-320.jpg)
![in a small beaker tared together with a glass stirring rod, and thrice its
volume of absolute alcohol added. On stirring, the gelatin sets firmly on
the rod and sides of the beaker, and may be washed with dilute alcohol
or even with cold water, dried and weighed. A very pure French gelatin
gave 98·6 per cent., while a common bone-glue only yielded about 60
per cent. precipitate. Absolute alcohol withdraws water from gelatin-
jelly, leaving a horny mass. Gelatin may also be precipitated completely
by saturating its solution with sodium chloride, and then acidifying
slightly with sulphuric or hydrochloric acid; and masses of jelly become
hardened in acidified salt solution as in alcohol, though a neutral
solution has little effect. The cause of this is difficult of explanation, but
its bearing on the pickling of sheep-skins (p. 89) and the production of
white leather (p. 186) is obvious.
Decompositions.—When aqueous solutions of gelatin are heated
under pressure, or in presence of glycerin and other bodies which raise
the boiling-point, or more slowly at lower temperatures, they gradually
lose the power of gelatinising on cooling, the gelatin being converted
into modifications soluble in cold water, but still capable of being
precipitated by tannin. Hofmeister[31] states that the gelatin takes up 3
molecules water and is split up into hemicollin, soluble in alcohol and
not precipitated by platinic chloride solution; and semiglutin, insoluble
in alcohol and precipitated by platinic chloride solution. Both are
precipitated by mercuric chloride. Dry gelatin is soluble in glycerin at
high temperatures, but probably suffers a similar change. Hence high
temperatures and long-continued heating must be avoided in gelatin
manufacture; and in making printers’ roller compositions, which are
mixtures of gelatin and glycerin, the gelatin must be swollen with water
and melted at a low temperature with the glycerin.
[31] Bied. Centr., 1880, p. 772, and Ch. Soc. Abs., 1881, p. 294.
Gelatin is also converted into soluble forms (peptones), perhaps
identical with the above, by the action of heat in presence of dilute
acids and alkalies. These, like gelatin, are precipitated by tannin and by
metaphosphoric acid.[32] Heated for longer periods or to higher
temperatures with aqueous solutions of the caustic alkalies, baryta, or
lime, gelatin is gradually broken down into simpler and simpler
products, ending in nitrogen or ammonia, water and carbonic acid.](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-60-320.jpg)
![Among the intermediate products may be mentioned various acids of
the amido-acetic series, as amido-acetic (glycocine, glycocoll), amido-
propionic (alanine), and amido-caproic (leucine); and of the amido-
succinic series (amido-succinic = aspartic acid).[33]
[32] Lorenz, Pflüger’s Arch., xlvii. pp. 189-95; Journ. Chem. Soc., 1891, A.
p. 477.
[33] Compare Schützenberger, Comptes Rend., cii. pp. 1296-9; Journ.
Chem. Soc., 1886, A. p. 818.
Treatment with acids produces very similar effects. The first products
are soluble peptones. Paal[34] on treating 100 parts of gelatin on the
water-bath with 160 parts water and 40 parts concentrated HCl till the
product was soluble in absolute alcohol, obtained, on purification, a
white hygroscopic mass of peptone salts containing 10-12 per cent. of
hydrochloric acid.[35]
[34] Berichte, xxv. pp. 1202-36; Journ. Chem. Soc., 1892, A. p. 895.
[35] See also Buchner and Curtius, Ber., xix. pp. 850-9; Journ. Chem. Soc.,
1886, A. p. 635.
The products of digestion of gelatin with gastric and pancreatic juice
are peptones which do not differ materially from gelatin in ultimate
composition, and the action is probably mainly hydrolytic.[36]
[36] Chittenden and Solly, Journ. Chem. Soc., 1891, A. p. 849.
The earlier products of putrefaction are very similar. Many bacteria
have the power of liquefying gelatin-jelly. This has been shown by
Brunton and McFadyen[37] to be due not to the direct action of the
bacteria, but to a soluble zymase secreted by them which peptonises
the gelatin. Its action is favoured by an alkaline condition, and
destroyed by a temperature of 100° C.[38] As putrefaction progresses,
the solution becomes very acid from the formation of butyric acid, and
later on ammonia and amido-acids are formed.
[37] R. S. Proc., xlvi. pp. 542-53.
[38] Compare pp. 17, 171; also Ch. Zeit., 1895, p. 1487.
Fahrion,[39] starting with the idea that albuminoids and gelatin were
condensation products of a lactone character (L.I.L.B. p. 185), and that
they might, like lactones, be depolymerised by saponification, digested
these bodies with alcoholic soda till they were dissolved, and on](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-61-320.jpg)
![neutralising the solution with hydrochloric acid, of which the excess was
driven off by repeated evaporation, and removing the sodium chloride
by treatment with alcohol, obtained in each case bodies of acid
reaction, which from their composition he supposed to be identical with
Schützenberger’s proteic acid, C8H14N2O4, which is soluble in water and
alcohol, insoluble in ether and petroleum, uncrystallisable, and forming
uncrystallisable salts. Fahrion suggested that the nitrogenous character
which Eitner attributed to his “dégras-former” (p. 370) was probably
due to contamination by this body; and that its formation might be
utilised in the analysis of leather and other proteid bodies. These
products have since been further investigated by Prof. Paal and Dr.
Schilling,[40] who show that they contain hydrochloric acid, to which
their acid reaction is due, and that they are identical with the peptone
salts previously obtained by Prof. Paal (v. s.) by digestion of proteids
with hydrochloric acid. The free peptones are strongly basic.
[39] Ch. Zeit., 1895, p. 1000.
[40] Ch. Zeit., 1895, p. 1487.
By dry distillation of gelatin a mixture of pyrrol and pyridin bases are
produced. This is commercially obtained by the distillation of bones,
and is known as “bone oil,” or “Dippel’s animal oil.” Pyrrol, C4H5N,
resembles phloroglucol in giving a purple-red colour to fir wood
moistened with hydrochloric acid (p. 299).
Reactions of Gelatin.—Gelatin is precipitated by mercuric chloride, in
this respect resembling peptones, but not by potassium ferrocyanide,
by which it is distinguished from albuminoids, and it differs from
albumin in not being coagulated by heat. Solution of gelatin dissolves
considerable quantities of calcium phosphate; hence this is always
present in bone-glues. Gelatin and some of its decomposition products
are precipitated by metaphosphoric acid.[41] The precipitate contains
about 7 per cent. P2O5, but gradually loses it on washing. Various salts
diminish the solubility of gelatin in hot water, and especially those of
the alum type. Chrome alum and basic chrome salts are especially
powerful, rendering it practically insoluble. The addition of about 3 per
cent. ammonium or potassium dichromate causes glue or gelatin to
become insoluble by the action of light with the formation of basic salts](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-62-320.jpg)
![of chromium, and has been utilised in photography and as a waterproof
cement. Other colloids besides gelatin are similarly affected.
[41] Lorenz, Pflüger’s Archiv, xlvii. pp. 189-195.
Gelatin is precipitated by all tannins, even from very dilute solutions;
one containing only 0·2 grm. per liter is rendered distinctly turbid by
gallotannic acid or infusion of gall-nuts; but some other tannins give a
less sensitive reaction. The precipitate is soluble to a considerable
extent in excess of gelatin, so that in using the latter as a test for
traces of tannin care must be taken to add a very small quantity only.
The addition of a little alum renders the reaction more delicate.
Whether the precipitate is a definite chemical compound has been
disputed, as its composition varies according to whether gelatin or
tannin is in excess. Böttinger[42] states that the precipitate produced by
adding gelatin to excess of gallotannic acid contains 10·7 per cent. of
nitrogen, indicating the presence of 66 per cent. of gelatin on the
assumption that gelatin contains 16·5 per cent. N (see p. 57). Digested
with water at 130° C., the precipitate is decomposed, yielding a
solution which precipitates tannin, and probably indicating the
formation of a more acid compound. Gelatin with excess of oak-bark
tannin gives a precipitate containing 9·5 per cent. of nitrogen,
corresponding to 57·5 per cent. of gelatin. Treated with water at 150°
C., this precipitate yielded three products: one soluble in cold water,
another in hot only and one insoluble. On addition of a solution of
formaldehyde (formalin) to one of gelatin no visible action takes place
in the cold, unless the solution of gelatin be very concentrated and
alkaline, but on heating, the gelatin is rendered insoluble owing to the
formation of a compound with the formaldehyde. From the very small
amount of formalin which is required to produce formo-gelatin it is very
doubtful if this is a definite compound.
[42] Liebig’s Ann. der Ch., ccxliv. pp. 227-32.
Weiske[43] states that bone-gelatin, carefully freed from all mineral
matter, is not precipitated by tannin till a trace of a salt (e. g. sodium
chloride) is added. So far as is known, bone-gelatin is identical with
that of skin.
[43] Bied. Centr., 1883, p. 673.](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-63-320.jpg)
![Chondrin is the gelatinous body produced by the digestion of
cartilage with water at 120° C. for three hours. In most of its physical
properties it is identical with gelatin, but differs from the latter in being
precipitated from its solution in water by acetic acid, lead acetate,
alum, and the mineral acids when the latter are not present in excess.
Chondrin also differs from gelatin in producing a substance capable of
easily reducing cupric oxide when it is boiled for some time with dilute
mineral acids. It is extremely probable that chondrin is merely an
impure gelatine.[44]
[44] Cp. Petri, Berichte, xii. p. 267; Mörner, Skand. Archiv f. Physiol., i. pp.
210-243; and Journ. Chem. Soc., 1889, A. p. 736 and Zeit. Physiol.
Chem., 1895, xx. pp. 357-364; and Journ. Chem. Soc., 1895, A. i. p. 254.
See also Richter, Org. Chem., i. p. 559.
Coriin.—Rollet[45] has shown that when hide and other forms of
connective tissue are soaked in lime- or baryta-water, the fibres
become split up into finer fibrils, and as the action proceeds, these
again separate into still finer ones, till the ultimate fibrils are so fine as
to be only distinguished under a powerful microscope. At the same
time, the alkaline solution dissolves the substance which cemented the
fibres together, and this may be recovered by neutralising the solution
with acetic acid, when the substance is thrown down as a flocculent
precipitate. This was considered by Rollet to be an albuminoid
substance; but Reimer[46] has shown that it is much more closely allied
to the gelatinous fibres, and, indeed, is probably produced from them
by the action of the alkaline solution. Reimer used limed calf-skin for
his experiments, and subjected it to prolonged cleansing with distilled
water, so that all soluble parts must have been pretty thoroughly
removed beforehand. He then digested it in closed glasses with lime-
water for 7-8 days, and precipitated the clear solution with dilute acetic
acid. He found that the same portion of hide might be used again and
again, without becoming exhausted, which strongly supports the
supposition that the substance is merely a product of a partial
decomposition of the hide-fibre, and indeed that there is no distinct
“cementing substance,” but merely a difference in the hydration or
physical condition of the fibre substance which causes it to split more
readily in certain directions. The dissolved substance, which he called
“coriin,” was purified by repeated solution in lime-water and](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-64-320.jpg)
![reprecipitation by acetic acid. It was readily soluble in alkaline solutions
but not in dilute acids, though in some cases it became so swollen and
finely divided as to appear almost as if dissolved. It was, however, very
soluble in common salt solution of about 10 per cent., from which it
was precipitated both by the addition of much water and by saturating
the solution with salt. Reimer found that a 10 per cent. salt solution
was equally effective with lime-water in extracting coriin from the hide,
and that it was partially precipitated on the addition of acid, and
completely so on saturating the acidified solution with salt. Other salts
of the alkalies and alkaline earths acted in a similar manner, so that
Reimer was at first deceived when experimenting with baryta-water,
because, being more concentrated than lime-water, the coriin remained
dissolved in the barium salt formed on neutralising with acid, and it was
necessary to dilute before a precipitate could be obtained. The slightly
acid solution of coriin gave no precipitate either in the cold or on boiling
with potassium ferrocyanide, being thus distinguished from
albuminoids. The neutral or alkaline solution showed no precipitate with
iron or mercuric chloride, copper sulphate, or with neutral lead acetate;
but with basic lead acetate, basic iron sulphate, or an excess of tannin
a precipitate was produced. Reimer’s analysis showed: Carbon, 45·91;
hydrogen, 6·57; nitrogen, 17·82; oxygen, 29·60; and he gives a
formula showing its relation to the original fibre, which does not seem
supported by sufficient evidence. In all probability coriin is merely an
impure degradation-product of hide-fibre or gelatin.
[45] Sitz. Wiener Akad., xxxix. p. 305.
[46] Ding. Polyt. Journ., ccv. p. 153.
Hide Albumin.—The fresh hide contains a portion of actual albumin,
viz. that of the blood-serum and of the lymph, which is not only
contained in the abundant blood-vessels, but saturates the fibrous
connective tissue, of which it forms the nourishment. This albumin is
mostly removed from the skin by the liming and working on the beam,
which is preparatory to tanning. Probably for sole-leather, the albumin
itself would be rather advantageous if left in the hide, as it combines
with tannin, and would assist in giving firmness and weight to the
leather. It is, however, for reasons which will be seen hereafter,
absolutely necessary to get rid of any lime which may be in](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-65-320.jpg)
![combination with it. The blood must also be thoroughly cleansed from
the hide before tanning, as its colouring matter contains iron, which, by
combination with the tannin, produces a bad colour.
The albumins form a class of closely allied bodies of which white of
egg may be taken as a type. They are also related to the casein of milk,
to fibrin, and more distantly to gelatin. A good deal of information on
the class may be found in Watt’s Dict. of Chem., 2nd ed., article
‘Proteids,’ and Beilstein’s article ‘Albuminaten,’ and in Allen’s
‘Commercial Organic Analysis,’ vol. iv.
The most characteristic property of albumins is that of coagulation by
heat. The temperature at which this takes place differs somewhat in
different members of the group, egg and serum albumin coagulating at
72-73° C. Dry albumins become insoluble if heated to 110° C. for some
time. Traces of acid tend slightly to lower, and traces of alkali to raise
the temperature of coagulation. Sodium chloride and some other
neutral salts favour coagulation. Solutions of albumin become
opalescent at a temperature slightly below that at which flakes form.
Albumins are also coagulated by alcohol and by strong mineral acids.
Coagulated albumin is only soluble in strong acids and alkalies by aid of
heat, and strongly resembles keratin (pp. 56, 68).
Solutions of albumin are lævorotatory to polarised light.
“Acid” and “Alkali” Albumins are formed by the action, in the cold, of
dilute acids (such as acetic, hydrochloric) and alkalies on albumin
solution. They are uncoagulable by heat, and are precipitated by careful
neutralisation, but are soluble in excess of either acid or alkali, or
alkaline carbonates. They are thrown out of solution by saturation with
sodium chloride or magnesium sulphate. It is doubtful whether
albumins combine with either acids or bases, and it is probable that the
“acid” or “alkali” albumins are identical with the parapeptones formed
in the first stage of peptic digestion.
On putrefaction, or on more severe treatment with acids and alkalies,
albumins break down in a way similar to gelatin, and yield almost
identical products (see p. 57); amido-acids of the acetic series, and
tyrosin (para-oxy-α-amido-phenyl-propionic acid) and aspartic (amido-
succinic) acid, being the most important.
Treatment with alcoholic soda (see p. 62) yields peptones similar to
those of gelatin.[47]](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-66-320.jpg)
![[47] Paal, Ch. Zeit., 1895, p. 1487.
Heated for some days with dilute nitric acid (1 : 2) all proteids,
including albumins, gelatin and keratins, yield yellow flocks of “xantho-
proteic acid,” a substance of somewhat indefinite composition, soluble
in ammonia and in fixed caustic alkalies with production of an orange-
red or brownish-red colour.
Millon’s reagent gives an intense red coloration when heated with
albumins, keratins, or gelatin. The reagent is made by dissolving 2·5
grm. of mercury in 20 c.c. of concentrated nitric acid, adding 50 c.c. of
water, allowing to settle and then decanting the clear liquid.
Albumins, previously purified by boiling with alcohol and washing
with ether, when dissolved in concentrated hydrochloric acid (sp. gr.
1·196) by aid of heat, give a violet-blue coloration, but the reaction is
often somewhat indefinite. Gelatin, chondrin and keratins do not give
this reaction.
Treated with a trace of cupric sulphate and excess of caustic potash
solution, albumins give a violet, and gelatin and peptones a pink
solution (biuret reaction).
Dissolved in glacial acetic acid and treated with concentrated
sulphuric acid, albumins and peptones give a violet and feebly
fluorescent solution. A somewhat similar reaction is obtained if sugar
solution be substituted for acetic acid.
A solution of albumin rendered strongly acid with acetic acid is
precipitated by potassium ferrocyanide, salt, sodium sulphate, lead
acetate, mercuric chloride, tannin and picric and tungstic acids.
Egg-Albumin is contained in the whites of eggs in membranes which
are broken up by beating with water and can then be removed by
filtration. When fresh its reaction is slightly alkaline, and it is
lævorotatory.
According to Lehmann, white of egg contains 87 per cent. of water,
and 13 per cent. of solid matter, the latter being almost entirely
composed of egg-albumin. This latter coagulates and becomes
insoluble in water on heating to 60° C.
Vitellin (the albumin or globulin[48] of the yolk) is insoluble in water,
and is obtained as a white granular residue on extracting undried egg-
yolk with large quantities of ether. It closely resembles myosin, the
chief globulin of muscle, but differs from other globulins in being](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-67-320.jpg)
![soluble in a saturated solution of common salt. A neutral solution of
vitellin in very dilute brine coagulates at 70-75° C.
[48] Globulin is an albumin soluble in dilute salt solutions, but insoluble in
water.
Yolks of eggs, preserved by the addition of salt, borax, or formalin,
are used for dressing skins in the process of “tawing” (see p. 191). For
the analysis of such yolks, see L.I.L.B., p. 159. Their most important
constituent for the leather-dresser is egg-oil of which they contain
about 30 per cent.
Casein, the principal proteid of milk, may be mentioned here in
connection with the albumins to which it is closely related, since,
though in no way connected with the animal skin, since it is used to
some extent as a “seasoning” or glaze for leather, for which it is well
adapted, and it is now to a considerable extent a waste product of
butter manufacture. It differs from albumins in being very incompletely
if at all coagulated by boiling, but separates at once in curdy flakes on
the addition of acids (hydrochloric, acetic, butyric), and by the action of
rennet. The curd is easily soluble in small quantities of dilute alkalies,
lime-water, and salts of alkaline reaction, such as sodium carbonate and
borax. If no more than the necessary quantity of alkali is employed for
solution, the compound has an acid reaction to phenolphthalein, and
like the original milk, is curdled by rennet and dilute acids. Casein may
also be dissolved by digestion with diluted mineral or organic acids.
Hair, Epidermis and Glands.—These are all derived from the epithelial
layer, and hence, as might be inferred, have much in common in their
chemical constitution. They are all classed by chemists under one
name, “keratin,” or horny tissue, and their ultimate analysis shows that
in elementary composition they closely resemble the albumins. It is
evident, however, that the horny tissues are a class rather than a single
compound.
The keratins are gradually loosened by prolonged soaking in water,
and, by continued boiling in a Papin’s digester at 160° C., evolve
sulphuretted hydrogen, at the same time dissolving to a turbid solution
which does not gelatinise on cooling. Keratin is dissolved by caustic
alkalies; the epidermis and the softer horny tissues are easily attacked,
while hair and horn require strong solutions and the aid of heat to
effect complete solution. The caustic alkaline earths act in the same](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-68-320.jpg)
![Fig. 18.—Kjeldahl Apparatus.
The colourless liquid is allowed to cool thoroughly, and the flask is
then fitted with a tapped funnel and tube, as shown in Fig. 18. This
tube must not be less than 4 mm. in diameter, and with the end in the
flask cut diagonally to facilitate drops of liquid falling back again into
the flask. It rises obliquely for a height of 12 to 15 inches, is then bent
over as shown in the figure and connected by a rubber tube[49] to a
100 c.c. pipette, or similarly shaped tube, the other end of which dips
just below the surface of a volume of exactly 50 c.c. of “normal”
hydrochloric acid contained in a second flask. About 50 c.c. of distilled
water is introduced into the flask containing the treated sample, and
after this 100 c.c. of a solution of 50 grams of caustic soda in 100 c.c.
of water is carefully and slowly run into the flask by means of the
tapped funnel with which it is provided. The contents of the flask are](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-71-320.jpg)
![now boiled for about half an hour,[50] the normal acid in the receiving
flask being kept cool by immersing the latter in cold water. The liquid in
this second flask is then titrated with normal sodium carbonate, using
methyl orange as indicator. The difference in c.c. between 50 c.c., the
volume of acid used, and the quantity of normal sodium carbonate
required to neutralise it, when multiplied by 0·014 represents the
amount of nitrogen (in grams) in the weight of the substance used for
the determination; or if multiplied by 0·0786 shows the weight of hide-
fibre in the same quantity of material. Some chemists add copper
sulphate, or a drop of mercury before boiling up the substance with the
strong sulphuric acid, but the use of such substances introduces
complications in the process without, in the case of gelatinous matter,
securing more accurate results. It is absolutely necessary that the acids
and alkali used should be free from ammonia, and a blank experiment
should be made using pure sugar which contains no nitrogen, and a
correction applied if necessary for the ammonia they contain.[51]
[49] The ends of the glass tubes should fit closely together, so as to expose
the rubber as little as possible to the action of ammoniacal vapour.
[50] “Bumping” is often very troublesome at this stage, and may be
prevented by passing a current of steam from another flask, or
ammonia-free air through a tube with a capillary opening into the boiling
liquid; fragments of pure zinc, of platinum, or broken tobacco-pipe are
much less efficient. It is an additional safeguard against the escape of
ammonia to fix a small absorption-tube containing fragments of glass to
the absorption-flask. The normal acid is run through this tube into the
flask, so as to wet the broken glass, and is finally rinsed into the
absorption flask before titrating its contents.
[51] Cp. Procter and Turnbull, Jour. Soc. Chem. Ind., 1900, p. 130; also
Nihoul, Composition des Cuirs Belges, p. 14 (Bourse aux Cuirs de Liège,
Sept. 1901), who advocates the use of potassium permanganate in the
oxidation; and Law (Jour. Soc. Ch. Ind., 1902, p. 847).
In place of using 10 grm. of potassium persulphate as described, 10 grm.
of ordinary potassium sulphate may be used, and potassium persulphate
added in small quantities towards the end of the operation till a perfectly
colourless solution is obtained.](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-72-320.jpg)
![The molecules usually consist of groups of atoms. Thus in the vapour
of water, each molecule contains one atom of oxygen combined with
two of hydrogen, and it is only at immense temperatures that this inner
grouping is broken up. Naturally, the more complicated and heavier the
molecular group, the more easily it is broken up by outside causes into
simpler groupings, and molecules may exist in liquids or solids, which
break up before they reach the gaseous form. Of such substances the
chemist says that they “cannot be volatilised without decomposition.” In
very rare instances does the gaseous molecule consist of a single atom;
even those of the most perfect gases, such as hydrogen, oxygen and
nitrogen consist of pairs which are not broken up at any known
temperature. The pressure of a gas, and its tendency to expand is due
simply to the motion and impact of its flying molecules, and it may be
noted that at the same temperature and pressure equal volumes of all
gases have the same number of molecules, the lighter molecules
making up for their want of weight by their greater velocity. The
average velocity of a molecule of oxygen (O2) at freezing point is 461
meters per second or about that of a rifle-bullet. It must not be taken
however, that in any given solid, liquid, or gas, all the molecules at any
temperature move at a uniform velocity, but that each individual
molecule may vary from moment to moment from rest up to a very
high speed, while the temperature of the mass only represents the
average. Thus it happens that in all liquids, and even in solids, a certain
proportion of the molecules at any temperature will have a speed
sufficient to enable them to leave the surface, and take the form of
vapour, while a certain proportion will fall back and be caught and
retained. Thus every liquid, and theoretically every solid, has a “vapour-
pressure,” rising with the temperature, and depending on it only, and at
the boiling temperature of the liquid equal to that of the atmosphere,
or about 15 lb. per square inch, and therefore able to form bubbles in
the interior of the liquid. If a little of a liquid is confined in a flask, the
flask will become filled with its vapour, and so long as any of the liquid
is present, the pressure of the vapour will depend only on the
temperature and not at all on the respective quantities of liquid or
vapour. Neither will it be affected by the pressure of other vapours or
gases present in the flask, the total pressure in which will be the sum
of the “partial” pressures of all the gases and vapours present.[52]](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-75-320.jpg)
![[52] Cp. p. 421.
The behaviour of gases and vapours has been described in some
detail because it possesses very close analogy to that of substances in
solution. The molecules of liquids are held together by attractions which
are very powerful over the short distances which separate them,
amounting in most cases to many tons per square centimeter of
sectional area, but the range over which they act is very small. In the
interior of the liquid the attractions on one side of a molecule are of
course exactly balanced by those on the opposite side, so that it is free
to move within the liquid without hindrance, but at the surface a very
small part of the force due to the attractions of the surface-layer is
unbalanced and acts as a sort of elastic skin holding the liquid together,
and is called “surface-tension.” Familiar examples of this are found in
the force which supports a drop on the end of a tube, the possibility of
laying a slightly oily needle on the surface of water without sinking, and
the ability of some flies to walk on water as if it were covered with a
sheet of india-rubber. Many liquids will mix or dissolve in each other in
any proportions, e.g. water and alcohol; the attraction of the alcohol for
the water-molecule being as great or greater than that of alcohol for
alcohol, or water for water. In other cases, such as water and oil, or
water and petroleum spirit, practically no mixture takes place, their
mutual attraction being small; and each retains a considerable surface-
tension at the points of contact, though less than that of the free
surfaces, since each exerts an attraction on the other. There are also
many intermediate cases, such as water with chloroform, carbolic acid,
or ether, in which each solvent dissolves a portion of the other, but the
two solutions do not mix, but form separate layers. In these cases an
equilibrium is attained, in which there is just as much tendency for
either of the liquids to pass into as out of the other layer. In this there
is an extraordinary resemblance to what has been said of vapour-
pressures; and the tendency to pass into solution is often called
solution-pressure; and it may be noted that when equilibrium has been
reached, not only is the solution-pressure, but the vapour-pressure of
each constituent equal in both solutions. Like vapour-pressures, the
solution-pressures usually increase with rise of temperature, more of
each constituent passing into the other, till at last the composition of
the two layers becomes identical, their surface-tensions disappear, and](https://image.slidesharecdn.com/25504252-250511125812-1a44e5fc/85/Theories-And-Models-Of-Communication-Paul-Cobley-Editor-Peter-J-Schulz-Editor-76-320.jpg)
Theories And Models Of Communication Paul Cobley Editor Peter J Schulz Editor
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- 5. Paul Cobley and Peter J. Schulz (Eds.) Theories and Models of Communication
- 6. Handbooks of Communication Science Edited by Peter J. Schulz and Paul Cobley Volume 1
- 7. Theories and Models of Communication Edited by Paul Cobley and Peter J. Schulz DE GRUYTER MOUTON
- 8. The publication of this series has been partly funded by the Università della Svizzera italiana – University of Lugano. ISBN: 978-3-11-024044-3 e-ISBN: 978-3-11-024045-0 Library of Congress Cataloging-in-Publication Data A CIP catalog record for this book has been applied for at the Library of Congress Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available in the Internet at http://dnb.dnb.de. © 2013 Walter de Gruyter GmbH, Berlin/Boston Cover image: Oliver Rossi/Photographer’s Choice RF/Gettyimages Typesetting: Meta Systems, Wustermark Printing: Hubert & Co. GmbH & Co. KG, Göttingen ♾ Printed on acid-free paper Printed in Germany www.degruyter.com
- 9. Preface to Handbooks of Communication Science series This volume is part of the series Handbooks of Communication Science, published from 2012 onwards by de Gruyter Mouton. When our generation of scholars was in their undergraduate years, and one happened to be studying communication, a series like this one was hard to imagine. There was, in fact, such a dearth of basic and reference literature that trying to make one’s way in communication studies as our generation did would be unimaginable to today’s undergraduates in the field. In truth, there was simply nothing much to turn to when you needed to cast a first glance at the key objects in the field of communication. The situation in the United States was slightly different; nevertheless, it is only within the last genera- tion that the basic literature has really proliferated there. What one did when looking for an overview or just a quick reference was to turn to social science books in general, or to the handbooks or textbooks from the neighbouring disciplines such as psychology, sociology, political science, linguis- tics, and probably other fields. That situation has changed dramatically. There are more textbooks available on some subjects than even the most industrious undergraduate can read. The representative key multi-volume International Ency- clopedia of Communication has now been available for some years. Overviews of subfields of communication exist in abundance. There is no longer a dearth for the curious undergraduate, who might nevertheless overlook the abundance of printed material and Google whatever he or she wants to know, to find a suitable Wikipedia entry within seconds. ‘Overview literature’ in an academic discipline serves to draw a balance. There has been a demand and a necessity to draw that balance in the field of communica- tion and it is an indicator of the maturing of the discipline. Our project of a multi- volume series of Handbooks of Communication Science is a part of this coming-of- age movement of the field. It is certainly one of the largest endeavours of its kind within communication sciences, with almost two dozen volumes already planned. But it is also unique in its combination of several things. The series is a major publishing venture which aims to offer a portrait of the current state of the art in the study of communication. But it seeks to do more than just assemble our knowledge of communication structures and processes; it seeks to integrate this knowledge. It does so by offering comprehensive articles in all the volumes instead of small entries in the style of an encyclopedia. An exten- sive index in each Handbook in the series, serves the encyclopedic task of find relevant specific pieces of information. There are already several handbooks in sub-disciplines of communication sciences such as political communication, meth- odology, organisational communication – but none so far has tried to comprehen- sively cover the discipline as a whole.
- 10. vi Preface to Handbooks of Communication Science series For all that it is maturing, communication as a discipline is still young and one of its benefits is that it derives its theories and methods from a great variety of work in other, and often older, disciplines. One consequence of this is that there is a variety of approaches and traditions in the field. For the Handbooks in this series, this has created two necessities: commitment to a pluralism of approaches, and a commitment to honour the scholarly traditions of current work and its intel- lectual roots in the knowledge in earlier times. There is really no single object of communication sciences. However, if one were to posit one possible object it might be the human communicative act – often conceived as “someone communicates something to someone else.” This is the departure point for much study of communication and, in consonance with such study, it is also the departure point for this series of Handbooks. As such, the series does not attempt to adopt the untenable position of understanding communication sciences as the study of everything that can be conceived as communicating. Rather, while acknowledging that the study of communication must be multi- faceted or fragmented, it also recognizes two very general approaches to communi- cation which can be distinguished as: a) the semiotic or linguistic approach associ- ated particularly with the humanities and developed especially where the Romance languages have been dominant and b) a quantitative approach associated with the hard and the social sciences and developed, especially, within an Anglo-German tradition. Although the relationship between these two approaches and between theory and research has not always been straightforward, the series does not privi- lege one above the other. In being committed to a plurality of approaches it assumes that different camps have something to tell each other. In this way, the Handbooks aspire to be relevant for all approaches to communication. The specific designation “communication science” for the Handbooks should be taken to indi- cate this commitment to plurality; like “the study of communication,” it merely designates the disciplined, methodologically informed, institutionalized study of (human) communication. On an operational level, the series aims at meeting the needs of undergradu- ates, postgraduates, academics and researchers across the area of communication studies. Integrating knowledge of communication structures and processes, it is dedicated to cultural and epistemological diversity, covering work originating from around the globe and applying very different scholarly approaches. To this end, the series is divided into 6 sections: “Theories and Models of Communication”, “Messages, Codes and Channels”, “Mode of Address, Communicative Situations and Contexts”, “Methodologies”, “Application areas” and “Futures”. As readers will see, the first four sections are fixed; yet it is in the nature of our field that the “Application areas” will expand. It is inevitable that the futures for the field prom- ise to be intriguing with their proximity to the key concerns of human existence on this planet (and even beyond), with the continuing prospect in communication sciences that that future is increasingly susceptible of prediction.
- 11. Preface to Handbooks of Communication Science series vii Note: administration on this series has been funded by the Università della Svizzera italiana – University of Lugano. Thanks go to the president of the univer- sity, Professor Piero Martinoli, as well as to the administration director, Albino Zgraggen. Peter J. Schulz, Università della Svizzera italiana, Lugano Paul Cobley, London Metropolitan University
- 13. Contents Preface to Handbooks of Communication Science series v Paul Cobley and Peter J. Schulz 1 Introduction 1 William F. Eadie and Robin Goret 2 Theories and models of communication: foundations and heritage 17 I Theories and models Robert T. Craig 3 Constructing theories in communication research 39 Richard L. Lanigan 4 Information theories 59 Dirk Baecker 5 Systemic theories of communication 85 Philip Lieberman 6 Biological and neurological bases of communication 101 Gabriele Siegert and Bjørn von Rimscha 7 Economic bases of communication 123 Cees J. Hamelink 8 Normative bases for communication 147 Christopher Tindale 9 Models of communicative efficiency 163 John O. Greene and Elizabeth Dorrance Hall 10 Cognitive theories of communication 181 Jonathan T. Delafield-Butt and Colwyn Trevarthen 11 Theories of the development of human communication 199 Paul Cobley 12 Semiotic models of communication 223
- 14. x Contents Tim Wharton 13 Linguistic action theories of communication 241 Adrian Bangerter and Eric Mayor 14 Interactional theories of communication 257 Lijiang Shen 15 Communication as persuasion 273 Patricia Moy and Brandon J. Bosch 16 Theories of public opinion 289 David Crowley 17 Mediation theory 309 Kim Christian Schrøder 18 Socio-cultural models of communication 327 II Components of communication Charles C. Self 19 Who 351 Dale Hample 20 What 369 Pamela J. Shoemaker, Jaime Riccio and Philip R. Johnson 21 Whom 383 Davide Bolchini and Amy Shirong Lu 22 Channel 397 Mary Beth Oliver, Julia K. Woolley and Anthony M. Limperos 23 Effects 411 Biographical sketches 425 Index 431
- 15. Paul Cobley and Peter J. Schulz 1 Introduction Abstract: This essay introduces the current volume and also gives a sense of its contents in relation to the entire series of Handbooks of Communication Science. It considers two broad definitions of communication and the problems of the ‘objects’ of communication science. It gives a sense of how the terms ‘theory’ and ‘model’ are used in the volume as well as some of the dilemmas that have existed in the field in respect of theory. Keywords: Communication, definitions, theories, theory, models, research, object, science, interdisciplinarity 1 Defining communication and defining communication sciences This volume is the inaugural handbook in the multiple-volume Handbooks of Com- munication Science – a major publishing venture which aims to offer a portrait of the current ‘state of the art’ in the study of communication. It was thought appro- priate, then, that the first volume in the series of handbooks presented the main models and theories of communication, thus producing a sense of the frame in which much of the study of communication takes place. Yet, even before theories and models are considered, there needs to be an awareness of the problems involved in defining the object of communication science, in delineating the breadth of the domain of study and even the naming of the discipline which is devoted to research in that domain. Definitions of communication commonly refer to etymology. Usually, this involves noting that the Latin root of ‘communication’ – communicare – means ‘to share’ or ‘to be in relation with’ and has its own relations in English to ‘common,’ ‘commune,’ and ‘community,’ suggesting an act of ‘bringing together.’ (cf. Cobley 2008, Rosengren 2000: 1; Schement 1993: 11; Beattie 1981: 34). Yet, this seemingly inclusive and broad definition of communication is not the only one that arises from the invocation of etymology. Peters (2008; cf. Peters 1996 and Craig 2000), somewhat differently, notes that ‘communication’ arises from the Latin noun com- municatio, meaning a ‘sharing’ or ‘imparting’: arguably, this has little relation to terms such as union or unity, but rather links to the Latin munus (duty, gift). As such, its root senses have to do with change, exchange, and goods possessed by a number of people. These differently inflected senses of the roots of ‘communica- tion’ have consequences for the way that the object of ‘communication science’ is
- 16. 2 Paul Cobley and Peter J. Schulz conceived; but before expanding on this, let us consider how communication study has been understood. Communication study is very much a modern discipline; yet it also has a long tradition and deep roots in philosophy and rhetoric. It was only in the twentieth century that it developed into an organized field with its own institutional history, its own appointed professors and academic journals. At this point, ‘communication science’ developed out of several traditions, including those of the also recently developing psychology and sociology. Like these disciplines, it has a proliferation of foci. The National Communication Association (NCA) in the United States sees communication study as a discipline focusing on: how humans use verbal and nonverbal messages to create meaning in various contexts (from two person groups to mass audiences) across cultures using a variety of channels and media. The discipline is especially interested in the impact of those messages on human behavior. Communication as a discipline includes the study of communication in interpersonal relation- ships, groups, organizations, and across cultures; rhetorical theory and criticism; performance studies; argumentation and persuasion; technologically mediated communication; and popu- lar culture. (http://www.natcom.org, accessed 20 April 2012) What is important here, firstly, is that communication study is envisaged as a discipline in its own right, in the same way that psychology and sociology have become. This status was not achieved without struggle – Donsbach (2006: 439) cites the famous 1930 statement by Tönnies on the proposal for the establishment of ‘press research’ alongside sociology in the German academic system: “Why would we need press research within sociology? We don’t need a chicken or duck science within biology.” Contemplating this leads to two further observations about communication study as a field – its interdisciplinarity (Cooren 2012; Living- stone 2009) and its similarities with sociology – which will be considered further below. Secondly, the range of communication, the proliferation of communication science’s foci – across interpersonal relationships, groups, organizations, cul- tures – is crucial: communication study is no more to be defined solely as the study of mass media as it is to be depicted as focused on isolated linguistic exchanges between individuals. Although it is already a broad church and may have to become ever more Catholic in its embrace of communicative phenomena in the future, communica- tion science is not the study of everything that can be conceived as communicating. Instead, it can be described in terms of two very general approaches to its object which have come to a head in the last 100 years: – a semiotic or linguistic approach associated particularly with the humanities and developed especially where the Romance languages have been domi- nant; – a quantitative approach associated with the hard and the social sciences and developed, especially, within an Anglo-German tradition.
- 17. Introduction 3 These two broad approaches have informed investigation into communication both at the level of forming the discipline’s theory as well as its actual collection of data. Yet, the relationship between these approaches and between theory and research has not always been straightforward. Furthermore, the relationship has unfolded in the West largely independent of Asiatic culture and its different conceptions of the act of communication. The key factors in this uneven development are inherent in communication study and intimately connected; they concern both communica- tion study's fragmentation and its object. Before considering these, a few words should be offered on the designation ‘communication science.’ In the last century and a half, many disciplines have claimed ‘scientific’ status for themselves. Often, the claim is made to bolster that discipline, giving it a reputation for truth and rigour that it may not necessarily deserve. The claim has sometimes assisted institutionalization of disciplines, underpinning the establishment of university departments and the winning of grants for research in the area. On the other hand, and often as a backlash, the term ‘science’ has sometimes been considered derogatory or precisely indicative of an undeserved status. Particularly in the ‘postmodern’ moment in which science has been one of the ‘grand’ or ‘metanarratives’ (Lyotard 1984) to which people have expressed credulity, it has been assumed not only that science does not embody a narrative of progress but that it is open to question for its self-justifications, its vacillations, its uncertainty, its sexist and other ideological pre-dispositions. There is understandable resistance, therefore, to the term ‘communication science.’ Yet, the study of communication has not just been the province of Anglophone acade- mia. Indeed, arguably its major constituency is in Germany. Certainly, communica- tion study is pursued at a consolidated institutional level not just in the UK and North America but in a number of European countries and, increasingly, in Asia. In these areas ‘science’ tends to have a connotation which differs from that of the English term and is associated, instead, simply with disciplinary rigour and the virtues of the higher learning in general, in contrast to, say, anecdotal or journalis- tic accounts of phenomena. As such, ‘communication science,’ like ‘the study of communication,’ designates the disciplined, methodologically informed, institu- tionalized study of communication rather than the guaranteed path to truth and progress (see also Craig, Chapter 3). However, it is clear that one problem regarding how communication science derives or constructs its models – a problem that informs the concern over the designation ‘science’ – arises over communication study’s object and its fragmentation. 1.1 Communication science and its objects A concern about communication science as a discipline is its very fragmentation. It is a domain made up of many sub-domains and sub-disciplines. This is undenia-
- 18. 4 Paul Cobley and Peter J. Schulz ble; yet the domain of communication has all the attributes that render it an estab- lished discipline. It is an institutionalized field, with journals, associations, depart- mental structures, professorial chairs and all the paraphernalia contributing to the organization of attempts to maintain quality of investigation and scientific status. As with any other rigorous discipline, one can find out about its key issues by consulting a large number of core journals, esteemed and peer-reviewed, as well as journals that may have less esteem for varying reasons. The discipline, like any other, monitors rigour in its research methods which are recognized by numerous national research councils. In Europe, the subject area is well embedded in univer- sities in countries such as Germany, Denmark, the Netherlands, Belgium, Sweden, Norway, Spain, parts of Italy, Switzerland, Austria (with the UK as an anomalous case where, notwithstanding the London School of Economics, communication study has not formally embedded itself in the elite universities, although media studies is strong in a number of other UK universities). The European Communica- tion and Research Association (ECREA), is the result of a merger of a number of relatively powerful communication associations across Europe. In the USA, com- munication science is professionally organized by the National Communication Association (NCA) and international organizations, including the International Communication Association (ICA). In Africa, the most prominent communication association is probably the South African Communication Association (SACOMM). In Asia, besides several national organizations, there is the Pacific and Asian Com- munication Association (PACA). It should be remembered, though, that communi- cation study is not just concentrated in the work of professional societies and institutional structures. At the margins of the field and domain there is much work that is not easily assimilated into professional concerns and, in some cases, is not currently easy to assimilate into the project of communication science as a whole. Examples might include the output of researchers and teachers working on scripts, some journalism, creative writing, some aspects of communicative efficiency, and so on. This last point has a direct bearing on the conceptualizing of communication science and how it develops theories and models in that it raises the issue of what might be the object of this discipline. If we were to compare communication sci- ence with medicine, the immediate impression is that the latter seems to have a clearer, defined sense of its object – there may be some local debate about what medicine’s object is, but there is a clear consensus regarding what medicine is not about. Communication study is different: there is no clear consensus regarding its object and, indeed, it is constantly compelled to chase new objects. In a case of appendicitis, medicine will employ such procedures as diagnosis, prognosis, sur- gery, medical and biochemical analysis of the inflammation and so on (notwith- standing the possibility of interrogating the matter with reference to medical sociol- ogy, health psychology and other means allied to medicine). What is outstanding is that in such cases medicine has a clear sense of pathology (one can say this to
- 19. Introduction 5 an extent about psychology, too). As such, appendicitis is palpably ‘bad,’ an ‘evil’ that demands cure or amelioration. However, the equivalent situation does not hold in communication science. Many people, including communication research- ers and teachers, may believe that the communication phenomenon of pornogra- phy is ‘bad’; but there is certainly no consensus on this issue. For communication science, it is still difficult to arrive at a foolproof definition of pornography. In the second place, a definitive account of the ‘effects’ – if any – of pornography on all people, of all different kinds, is a long way away. The object of communication science is therefore underdetermined and inescapably so. Furthermore, there are numerous reasons for this. If we take an example from the foundation of medicine, we know that Hippocrates (1983 [c. 430–330 bc]: 185) advanced medical science by observing that a symptom exists as such when it is found to be identical in Delos, Scythia and in Libya. Where the object of communications is concerned, the opposite is the case: the object will be subject to sometimes significantly differ- ent degrees of difference according to geography and context. This is the reason, too, that the study of communication can never be organized according to the implementation of just one method, typically either adopted from a social science template or from a humanities one. The frequently extreme variation and richness of the cultural context in which communication takes place dictates that a diverse set of methods is crucial to the task of attempting to unravel the nature of commu- nication in different places and contexts. This is not to say that the object of com- munication science can be simply summed up as ‘cultural signs’ or ‘signs in con- text.’ Whilst these are dominant in communication science, there are also endeavours which serve to illustrate the illusory basis of the nature/culture divide. One of these is the investigation of communication disorders (Rieber 1981; Damico et al. 2010); another is biosemiotics (see Cobley, Chapter 12). Unlike medicine, then, it is difficult to say what communication science is not about. Communication is sufficiently general that it suffuses other disciplines or objects. This is so to the extent that it is even easy to find examples in which the interaction of cells or other organic entities are said to be involved in ‘communica- tion.’ Often, this term is used in a self-consciously metaphorical way. Yet, on the same level, it would be strange to encounter a sociology of neurons or the philoso- phy of metals. Communication science, of course, is not alone in having a diverse profusion of objects. Because of their focus on objects which change according to issues of sociality, geography, time, and context, both communication and sociol- ogy, despite their many differences, are fragmented. Communication science and psychology, again with many differences, have a slightly different experience of fragmentation, with the latter discipline being fragmented in some areas and uni- fied in others. There is really no single object of communication science. However, if one were to posit one possible object it might be the human communicative act – often conceived as “someone communicates something to someone else”. This, of course, is the thread of one of the most fundamental models of communication
- 20. 6 Paul Cobley and Peter J. Schulz offered by Lasswell (1948: 37): “Who says what to whom in what channel and with what effect?” Of course, it is well known that Lasswell’s model leaves out all man- ner of noise and contextual matters as well as embedding assumptions such as that there is necessarily any ‘effect’ in communications. The contributions in Sec- tion 2 of this volume, ‘Components of communication,’ are very much alive to this fact and point out the most salient shortcomings of the model where relevant. Indeed, we might add that in addition to questioning the character of the ‘who,’ ‘what,’ ‘whom,’ ‘channel’ and ‘effect,’ it would not be impossible to make a credi- ble argument about the way in which the elements in between – ‘says’ (glottocen- tric), ‘to’ (attributing intentionality), ‘in’ (a spatial metaphor privileging dissemina- tion over representation), ‘and with what’ (assuming an attuned destination) – are open to criticism because they do not account for the entirety of the vicissitudes of communications. Nevertheless, as a hook for discussion and as a short mnemonic for recalling the general object of communication science, Lasswell’s formula still serves. There is a problem, though, with too great a degree of generality in the study of communication. The idea of ‘pan-communication,’ for example – the belief that everything communicates in some way or another – is one possible position that could be taken in communication. However, it is not desirable for this series of Handbooks nor, we believe, for communication science as a whole. There are a number of reasons for this. Firstly, it is not clear that everything does communi- cate. There are some objects which harbour the potential to communicate but sel- dom do play a part in the world of communication; there are also things which remain resolutely on the fringes of experience and are not considered in their capacity – however limited – to communicate. More importantly, a pan-communi- cation perspective tends to prevent rather than promote investigation; it presents an unlimited array of objects about which it is difficult say anything regarding what unifies them or in what way they are related. As with all academic work, communication science is compelled to identify common features and patterns which will illuminate the workings of its objects. Indeed, in the etymologically- inflected definitions at the commencement of this Introduction, there are clear imperatives with respect to this task. One definition – invoking ‘community’ and ‘bringing together’ – tends towards a proliferation of communication science’s objects; the other – focusing on exchange, gift, participation and the way that a municipal impulse creates an event – lends itself to a more specific set of contextu- alized objects or processes. At the root of communication science, to be sure, it is possible that a broad conception of communication would be tenable. This would include communication among animals and plants. However, communication sci- entists have been mindful of the fact that the entire field would be untenable if its central conception of communication was too broad. The way that communication science has so far manifested itself has meant that the key concern has been with human communication. There remains a residual concern about the extent to
- 21. Introduction 7 which there is continuity of communication, from plants, through animals, to humans, plus a concomitant concern that ‘communication’ as applied to say, cells, is merely ‘metaphorical’ but, as yet, this has not been developed. Yet, it should be qualified that, insofar as communication science takes as its object human communication, the act of ‘communication’ is not reified. What the study of com- munication is concerned with is not communication as a material and ‘finished’ entity. Rather, it is concerned with the manifold nature of human behaviour in communication. Stating this does not amount to sympathy with the discredited project of ‘behaviourism,’ nor is it an alignment with the so-called behavioural sciences. Instead, it indicates that the object of communication science is an empir- ical entity which, far from being stable and consisting of matter, is susceptible to the vagaries of changes in human behaviour and historical forces. 1.2 Defining communication theories and models One of the great achievements in the definition of communication science in recent years has been the International Encyclopedia of Communication in 12 volumes (2008) edited by Wolfgang Donsbach. It represents a major step in the task of establishing a sense of the range of objects of communication science. However, in its definition of terms and outlining of topics, it is not necessarily designed to offer a sense of ongoing research, the ‘state of the art’ in communication science or an overview of the materials that will equip the field to meet future challenges. We see the present series of Handbooks of which the current volume is the first as the next step in the Encyclopedia’s synoptic work. Important to the current project is the constitution of the field – for this reason, the editors of the other Handbooks and the contributors to this volume are leading and agenda-setting scholars. The task for this volume, ahead of the other Handbooks, is to consider the rough struc- ture for the field that arises from the range of its pursuits (intercultural communi- cation, organizational communication, broadcasting and so forth), to set this against the areas of communication science that are established globally (the study of communicative competence, rhetoric, political communication including ‘influ- ence,’ ‘persuasion,’ etc., commercial communication, also including ‘influence,’ ‘persuasion,’ etc., the study of media) and rising fields such as the study of com- munication technology or health communication, and to focus on the key models/ theories that have developed sometimes from specific areas but have had conse- quences for communication study as a whole. To do this, of course, we need to have an understanding of what constitutes a ‘model’ or ‘theory.’ As a field, commu- nication science has been very profligate in its spawning and naming of theories locally. Part of this volume’s remit is to decide what a ‘theory’ or ‘model’ is as well as presenting the most important of these. As a start, we can describe a model as a simplified picture of a part of the real world. It represents characteristics of reality, but only some of them. Like a picture,
- 22. 8 Paul Cobley and Peter J. Schulz a model is much simpler than the phenomena it is supposed to represent or explain. For example, a model of an aeroplane resembles the real aeroplane with respect to some parts of an aeroplane – wings, tail, wheels, etc. – although it is likely to miss other characteristics – for example, wing flaps and slats. Considering the model, we can learn something about the size or the proportion of wings and fuselage, but this would not necessarily tell us anything about its speed (see also Lanigan, Chapter 4). In a similar manner, a theory is supposed to represent or explain the phenom- ena to which it refers. There are plenty of definitions of what a theory is. Some scholars describe theory as a symbolic construction (Kaplan 1964: 296), others as “a set of interrelated constructs (concepts), definitions, and propositions that present a systematic view of phenomena by specifying relations among variables, with the purpose of explaining and predicting the phenomena” (Kerlinger and Lee 2000: 11). What is common in these as well as in other definitions is the fundamen- tal idea that a theory consists of abstract or concrete concepts or constructs that function as representations or means by which we are able to understand and handle the complex reality. Concepts are “building blocks” (Jaccard and Jacoby 2010: 10) for all thinking and understanding of the physical and social world around us, regardless of whether these blocks are used by scientists or non-scien- tists. In addition, a theory implies a statement about relationships between the concepts or constructs that are inherent to it. There are different types of such statements. These may connect concepts and constructs; in addition, many theo- ries in the social sciences include either relational or causal statements. A rela- tional statement describes the association or correlation between concepts. In prac- tice, it means that the existence of one concept conveys information about the existence of another concept. A causal statement, in contrast, means that one concept is considered to be the cause of a second concept. Despite the fact that theories differ in many respects and have been classified in different types of theo- ries, at the core of all theories stands the fundamental idea of a set of statements about the relationship between concepts or constructs (Jaccard and Jacoby 2010: 28). Something very similar applies also to models: they always include con- cepts, constructs and the relations between them. This is why, in this volume, both terms, theory and model, are used interchangeably. From this perspective, scientific knowledge of a discipline is basically nothing more than a corpus of theoretical statements in the aforementioned sense. Theoriz- ing or modelling includes the conceptualization of phenomena in terms of a set of concepts or constructs and relationships among them. Learning what a discipline is about and what is the common wisdom in this field means studying its major theories and models. That is what this first volume of the Handbooks series intends to do. Yet, it should be acknowledged that while theories have arisen in different areas of communication science, the work of forging theory is far from over. In an
- 23. Introduction 9 essay that has lost none of its acumen since it was written more than 20 years ago, Charles Berger (1991) asked (and answered!) the question of why there have been so few genuine communication theories. He found that certain historical legacies, a fixation on methodology at the expense of theory and risk aversion on the part of researchers had made theory parochial and almost utterly context-dependent. Not that much has changed since Berger’s essay and scholars in the field still struggle with the shortage of theories, for which new explanations were found since Berger described his. Many theories in the field have been borrowed from other disciplines, mainly from sociology, social psychology and political science, and adapted to the needs and interests of communication science. And, as Berger notes, communication science has not yet exported as much as it has imported from other fields; as such, communication research has not yet become an autono- mous scientific enterprise with its own theoretical frameworks. What often hap- pened was that communication theorists refined existing theoretical frameworks from other disciplines rather than developing their own which then could have been embraced by other disciplines. The question of why theories are so important in the field leads us to one additional observation. Communication science provides us with extensive knowl- edge about the world in which we live. Such knowledge of what happened in the past, what is happening right now and what will happen in the future would, however, be incomplete if it did not also tell us why certain events are likely to happen. So, communication theories provide us with an explanation for the phe- nomena they also describe (hopefully accurately). In fact, the explanation of observed phenomena is at the core of any theory. Once we are able to explain why certain things happen, this will also allow us, at least to a certain extent, to predict what is likely to happen in the future (see also Cobley, Chapter 12). Both explana- tion and prediction are constitutive parts of a theory. Both function as guidance regarding our understanding of some aspects of our experience: they allow us to say, with a high degree of probability, what is going to occur and re-occur. With respect to this explanatory power it is not difficult to understand why communica- tion science continues to claim that the field needs mainly theory-based research. Theories are good or useful to the extent that they explain, allow us to predict and to the extent that they fit our experience of events and reality. Theories may be rejected simply because they do not fit, meaning they do not make sense in light of our experience, or lack credibility. In the 1990s especially, postmodernism questioned the basic assumption in communication theory, which is based on the idea of fit – that is, the correspondence between the relations of concepts and constructs as conceived in theories, on the one side, and the empirical data that more or less fit these concepts and relations on the other side. Postmodern think- ing, in opposition to this idea, holds that correspondence or ‘consensus’ are intrin- sically modernist notions that lead to totalitarian and totalizing ways of thinking. Indeed, postmodernism implies that there cannot be one correspondence or con-
- 24. 10 Paul Cobley and Peter J. Schulz sensus but, instead, that there are many possible correspondences which are often in conflict with others. Additionally, postmodernism rejects the idea of a reason- ing, rational subject at the centre of any theory and replaces it with an ‘individual’ that is conceived of as a product of various discursive practices and knowledge structures. Without discussing the details of this critical approach toward theory, it should be sufficient to mention at this point that by the same token that post- modernism criticizes the traditional idea of theory, it also tends to imply that its own approach – based on the recognition of numerous contingent forces – is some- how more ‘fitting’. Ultimately, this prevents communication science from develop- ing sounder theories and ‘fits’ in the future. It threatens to be the end of a number of fields, but especially communication science. This is the case not so much because of postmodernism’s critique of consensus and empirical certainty; rather, it is because of the way that postmodernism has attempted to encourage communi- cation theory to shut up shop and to fall back on the risk aversion and fixation on methodology that Berger so cogently delineated. One of the objectives of the cur- rent book is to contribute to ensuring that this does not happen. 1.3 Theories and models in the field The way that theories and models are figured in this volume corresponds to the way in which the series of Handbooks has been conceived. The series aims to integrate knowledge of communication structures and processes, not to split them into little pieces. It is committed to a pluralistic approach to the field, both in terms of theories and methods. It is supposed to document the current state of knowledge in the field, whilst also describing the intellectual roots of that knowledge. It seeks a coherent terminology whilst acknowledging that this is not possible in all instan- ces. And it embraces any theory or model that can enlighten communication proc- esses. Following the present volume on theories and models of communication, the Handbooks are divided into five areas, the last being a single volume on the futures for communication science. The first area of volumes is on messages, codes and channels. Issues to do with these feature strongly in the current volume: the essays in this volume loosely arranged around Lasswell’s formula for communication study necessarily consider the message (especially ‘What’) and channel. The chan- nel, of course, takes in communication technology, verbality, nonverbality, and other visual communication. Code is particularly important in considering commu- nication because it has common and specialized definitions, involving either a very specific function or a more varied one associated with the many different forms of communication – verbal, nonverbal, specifically visual and connected to different communication technologies (see also Cobley, Chapter 12). Moreover, we must con- sider where and how the messages, channels and codes of communication are
- 25. Introduction 11 studied. The centrality of verbal communication to communication science derives to a great extent from its institutionalization. The history of the study of nonverbal communication is marked by its almost total lack of institutionalization globally. Visual communication (as opposed to, say, auditory communication) is an example of an area that has become institutionalized for specific historical reasons. The study of communication technology is remarkable for its rapid institutionalization and the fact that it is related to other endeavours by virtue of involving investiga- tion of the extensions of human processes. Models and theories of communication also need to attempt to account for the matters in the third section of volumes within this series: mode of address, communicative situations and contexts. Any kind of communication takes place in a given context – narrow, broad, intermediate, rule-bound – its mode. It is through mode (conceived in this way) that some traditions in communication science come together: interpersonal communication, small group communication, mass com- munication. Additionally, if one compares speech communication and mass com- munication, it is notable that they have much in common and study can be carried out on this basis. Yet, if the communication situation changes – for example, if the communication is taking place during a war – the comparison can be rendered invalid. Thus, there are fluctuating differences and similarities in interpersonal communication, mass communication and organizational communication that theories and models must take into account. Communication is also studied according to a range of methodologies which have been developed in the history of communication science for their honed abil- ity to address questions that arise from both communication in specific areas and communication across a number of areas. Commonly in research the object and method are intertwined. However, it should be remembered that what one finds is not always entirely determined by how one looks for it – sometimes research in a specific area of communications throws up unanticipated empirical developments. Some developments in some areas (obvious examples are developing technologies or burgeoning social networks) will create new research areas. So, whether one is carrying out research using quantitative or qualitative research methods in a par- ticular area of the communication landscape, theories and models are not extrane- ous. If studying the rapid growth of online social networks in the last decade, then the body of work on network theory (see Chapters 4, 5, 12 and 19 by Lanigan, Baecker, Cobley and Self respectively) should have enabled at least some contextu- alizing projection regarding the growth of contemporary social networking. In line with theory, as well as with new objects, research methods sometimes have to be adjusted. This may go hand-in-hand with the development of new (sub)fields and with consequent effects on the methodology of research in those (sub)fields. Jour- nals and publications in the field are usually taxed with the task of representing new methods and developments. As has been noted, one of the dilemmas facing theories and models of commu- nication is that the objects of communications seem to proliferate to such an extent
- 26. 12 Paul Cobley and Peter J. Schulz that they have created the impression of a very fragmented field. Even with the task of successfully representing the ‘state of the art,’ which is central to this Handbooks series, there is the problem of rapidly developing (sub)fields or ‘appli- cation areas’ before the series is finally complete. The growth of new areas with features that have not been anticipated can undermine communication models. This is especially the case in the present when it is clear that communication technology and its availability has meant that there are ‘amateur’ or ‘domestic’ producers of prominent communications (for example, citizen journalists) who would, in previous decades, be considered as mere consumers. This upsets, among other things, models of the audience in communications (see Chapter 21, Shoe- maker, Riccio and Johnson). Thus, the ‘application areas’ in this series of Hand- books will be covered by volumes on Health Communication, Educational/Instruc- tional Communication, Science Communication, Journalism and others. However, it may be necessary to supplement these in the coming years with volumes on such fast developing areas as crisis communication. Even at this stage, communication science is still a youthful field and the fact that vibrancy is problematic for the development of completely watertight theories and models is a small price to pay for the knowledge of human behaviour that its research yields. Ultimately, while theory is a conceptualization of phenomena in terms of a set of concepts or constructs and relationships among them, it is also a map helping those outside and within the field to find their way round. 2 Organization of the volume Each of the essays in this volume begins with an abstract foreshadowing what is to follow. For quicker reference, still, on the collection of essays as a whole and how to use the volume, some comments are offered here. Following this Introduction which has focused on communication study and its objects as a theoretical foundational matter for theories and models, Eadie and Goret’s Chapter 2 presents a historically-orientated overview of that matter. The volume is then divided into two sections. The first of these features 17 contributions which present the key theories or models of communication. The second section is made up of some short and more focused chapters on ‘components’ of communi- cation. The classic, five-point model of Lasswell has been taken as the departure point for this project: so there are chapters on how ‘Who’ has been conceived in communication study, as well as ‘What,’ ‘Whom,’ ‘Channel’ and ‘Effect.’ As has been seen, Lasswell’s model is far from being the final word on the components of communication and, as the chapters will show, even while serving as a basis, the model has had to be adapted or pronounced as lacking full adequacy in the face of communication’s mutability, fragmentation, geographical and contextual situatedness.
- 27. Introduction 13 The section on ‘Theories and models’ begins with Craig’s (Chapter 3) discus- sion of how theories and models are actually constructed in communication sci- ence. It gives a strong sense of the way that this takes place in the context of different disciplines. This is then followed by chapters that discuss particular models from specific areas of the study of communication or that have fed into contemporary communication science. Lanigan’s chapter (Chapter 4) pits informa- tion theory and its model of signification against communication theory with its model of meaning. Following this, Baecker’s chapter (Chapter 5) outlines systemic theories of communication in the wake of Shannon and Weaver’s 1949 model. The next three chapters find models in the ‘bases’ of communication. Lieber- man’s (Chapter 6) is concerned with the motor control, cognitive flexibility and creativity that give rise to communication in primates. Siegert and von Rimscha (Chapter 7) review networks and regulation as well as their consequences in con- sidering the economic bases of communication while Hamelink (Chapter 8) gives an overview of the key issues that make up the normative bases of human commu- nication: fairness in speech, freedom of speech, responsibility, confidentiality and truth in communication. In Chapter 9, Tindale considers the ways in which communication has been shown to be ‘efficient’ by way of the traditions of argumentation and rhetoric, plus more recent evaluations of the communication process by research into Artificial Intelligence. Chapter 10, by Greene and Dorrance Hall surveys the range of cogni- tive theories of communication, showing how they have sometimes been comple- mentary and sometimes competing, and offering some syntheses. Then Trevarthen and Delafield-Butt (Chapter 11), consider the evidence in human development which indicates that learning of communication, particularly ‘language,’ takes place from the ante-natal stage onwards. The three chapters that follow outline traditions that have had a considerable (sometimes unacknowledged) influence on communication. Chapter 12 by Cobley traces the way in which models of communication in semiotics, especially those giving rise to ‘code’ and ‘text,’ have contributed to communication science. Whar- ton (Chapter 13) discusses the bases of pragmatics or action-orientated theories of communication. Bangerter and Mayor (Chapter 14) then go on to consider the influ- ence of the action-orientation in attempts in communication science to understand the relations of communication and cognition. In the more demonstrably public environment of communication are the fol- lowing four chapters. Through the consideration of a range of findings from areas including cognitive dissonance, computational theories, dual process models and affectively-orientated theories, Shen (Chapter 15) discusses the way in which com- munication has been conceived in terms of its possibility to shape, reinforce, or change the responses others. Moy and Bosch (Chapter 16) discuss not only how public communication is theorized but also how it might be underpinned by norm- ative models of what constitutes ‘the public.’ Chapter 17 concentrates more on
- 28. 14 Paul Cobley and Peter J. Schulz media, with Crowley’s essay on meditation theories as explorations not just of media but also symbolic exchange and interaction. Finally in this section, Chap- ter 18 by Schrøder gives an account of socio-cultural models of communication in which the central exemplar is so-called ‘British cultural studies’ and, within that, Hall’s formulation of the encoding/decoding model. Section 2 addresses the components of communication within a loosely Lass- wellian frame. Chapter 19 by Self considers ‘Who’ in relation to ‘strong effects,’ ‘limited effects,’ ‘structural effects’ and ‘semiotic effects’ models. Chapter 20 on ‘What’ sees Hample considering the message in terms of the way that arguments are constructed. ‘Whom’ (Chapter 21) by Shoemaker, Riccio and Johnson looks at the ways in which audiences have been conceptualized over the last century and points to the way that models of audiences proposed by researchers have often been problematic because they have paid too little attention to change. In the essay on ‘Channel’ (Chapter 22), Bolchini and Lu see their subject in terms of the ‘instrumentation’ of communication and they analyse it in general terms and with reference to contemporary interactive media and the internet. Finally, Oliver, Lim- peros and Woolley (Chapter 23) interrogate models of ‘effect,’ identifying three broad classes: cumulative, immediate and interpretative. The chapters in the volume have been designed to be read on their own or in groups with other chapters in the volume or as a whole statement, along with the Introduction, of the current constitution of theory in communication science. The chapters cross-reference each other at different stages in order to reduce repetition and to provide easy access to fuller discussions of various issues. However, there is some necessary repetition – for example, the topic of ‘effects’ crops up in a number of places because it has played such a key role in ‘who,’ ‘what,’ ‘whom,’ ‘channel’ and fields such as ‘public communication.’ Each chapter encourages research beyond the confines of this volume by offering suggestions for further reading. References Beattie, Earle. 1981. Confused terminology in the field of communication, information and mass media: brillig but mimsy. Canadian Journal of Communication 8 (1). 32–55. Berger, Charles. 1991. Chautauqua: Why are there so few communication theories? Communication Monographs 58. 101–113. Cobley, Paul. 2008. Communication: definition and concepts. In: Wolfgang Donsbach (ed.), International encyclopedia of communication, Vol. II, 660–666. Malden, MA: Blackwell. Craig, Robert T. 2000. Communication. In: Thomas O. Sloane (ed.), Encyclopedia of rhetoric. New York: Oxford University Press. Cooren, François. 2012. Communication theory at the center. Ventriloquism and the communicative constitution of reality. Communication Theory 62 (1). 1–20. Damico, Jack S., Nicole Müller & Martin J. Ball. 2010. The handbook of language and speech disorders. New York: WileyBlackwell.
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- 31. William F. Eadie and Robin Goret 2 Theories and models of communication: foundations and heritage Abstract: This chapter charts the historical influences on the theories and models that shaped the communication discipline. It illustrates the importance of U.S. and European scholars from not only the beginnings of the communication discipline, but including those who were pre-eminent in other academic disciplines such as sociology, psychology, political science and journalism, as well as examining emerging scholarship from Asia that focuses on understanding cultural differences through communication theories. The chapter traces the foundations and heritage of communication study from five perspectives: (1) communication as shaper of public opinion; (2) communication as language use; (3) communication as infor- mation transmission; (4) communication as developer of relationships; and (5) communication as definer, interpreter, and critic of culture. Keywords: Public opinion, media messages, agenda setting theory, cultivation theory, language, cultural studies, rhetoric, general semantics, symbolic interac- tionism, relational communication Communication study seems inherently multi-disciplinary, drawing theory and sharing concepts from psychology, sociology, political science and other social sciences. Indeed, many of the scholars who are considered pre-eminent in commu- nication were not from the discipline of communication itself and the fact that their work shaped communication theory was a by-product and not the original intent of their work (Delia 1987; Rogers 1994). Communication has deep roots as an area of inquiry, but its history as an academic discipline is relatively brief. The most comprehensive ancient texts on communication to which we have access are those of the Greek and Roman socie- ties. In both societies, communication is defined as synonymous with rhetoric, although that term was contested between Plato and Aristotle. Plato, according to Peters’s (1999) analysis, defined rhetoric as fostering the ability for humans to connect as eros, or at a soulful level through stylish and poetic language, while Aristotle’s ideas about rhetoric are generally seen as explaining how humans influ- ence each other ethically in public fora. Aristotle’s ideas were frequently seen as cornerstones of democratic deliberation, while Plato’s ideas provided a foundation for the study of literature. The differences between them were sometimes simplified to style (“mere rhetoric”) vs. substance (rhetoric as an ancient and noble art). Nevertheless, major philosophers tended to write about rhetoric at least in passing. Rhetoric evolved distinctly from communication for at least half of the twentieth century, but eventually the two areas of study came to rival each other.
- 32. 18 William F. Eadie and Robin Goret Communication’s history is also somewhat contentious, as a communication disciplinary story starts with sociology and social psychology and then co-mingles with the study of journalism and speech before emerging as the dominant force in the stories of both of the latter (Eadie 2011). The study of communication developed primarily in the United States, though with considerable influence from European thinkers. In this chapter, we will trace some of the historical influences on contem- porary thought in the communication discipline. In doing so, we will draw on the influence of U. S. and European scholars on the development of our ideas about communication phenomena, and we will touch on some emerging scholarship from Asia that shows potential for understanding cultural differences through com- munication ideas. In structuring this chapter, we need to take into account differing ideas about the nature of communication. So, we will organize our survey around five broad categories of communication phenomena: (1) communication as shaper of public opinion; (2) communication as language use; (3) communication as information transmission; (4) communication as developer of relationships; and (5) communi- cation as definer, interpreter, and critic of culture. 1 Communication as shaper of public opinion Communication’s roots in the formation of public opinion stem from the develop- ment of sociology as a discipline, primarily at the University of Chicago. Deliber- ately located in the midst of a working class urban neighborhood, the university took as its mission the study of its surroundings as a laboratory for societal improvement. Robert Park, the head of the nascent program that would come to define the university’s mission, recognized early the role that communication tech- nology could play in society. Park’s (1922, 1952) theories of mass communication became the basis for his colleagues to begin to think, from a variety of perspectives, about how a variety of communication phenomena interacted with the formation and maintenance of society. It was a journalist who brought the idea of public opinion into focus, however. Newspaper columnist Walter Lippmann chose to write for public, rather than schol- arly consumption, but the thorough and eloquent manner in which he expressed his ideas led scholars to value his work. Lippmann’s (1922) book, Public Opinion, became a touchstone for scholarship for many years to come. Following World War I, concern arose in particular about the role of propa- ganda in shaping public opinion. Political scientist Harold Lasswell (1927) became an early advocate for studying how media could be used, particularly by govern- ments, to influence public opinion through biased or incomplete messages. Media were looked on as powerful forces that could potentially affect large numbers of people in similar ways. The wide-spread panic that set in following the Halloween
- 33. Theories and models of communication: foundations and heritage 19 radio broadcast of, The War of the Worlds, H. G. Wells’ story re-told as a series of radio news broadcasts, was seen as an example of the power of media to act as a “hypodermic needle” (Lowery and DeFleur 1995; Pooley 2006; Rogers 1994), inject- ing a powerful drug into the public consciousness. Concern about the rise of Nazism and Fascism in Europe led to the first con- certed research efforts in both mediated and face-to-face communication, in the 1930s. Interestingly, many of the scholars who participated in these efforts were European émigrés who sought to escape those two political movements. As outsid- ers (including Jews, who suffered under anti-Semitic attitudes then prevalent at major U. S. universities) these scholars found ways of supporting themselves by doing practical research on problems deemed to be of great interest either to U. S. corporations or to the government. From this research, which eventually was iden- tified with social psychology, came a tradition of quantitative study of communica- tion behavior. During World War II, the U. S. government gathered scholars together in Wash- ington, DC, to provide collective brainpower for managing the war effort and the sacrifices that were necessary at home. Research on propaganda and public opin- ion had already been underway in the 1920s and 1930s, and Paul Lazarsfeld and his associates’ (1944) study of the 1940 election (see below for details) had debunked the idea that mass media messages had direct effects on voting behavior. Rather, these effects were often modulated by pre-existing attitudes, such as politi- cal party allegiances, and by interactions with influential people (who were labeled “opinion leaders”). Research conducted on group interaction as a tool of persua- sion (e.g., Lewin 1943) demonstrated that commonly-held attitudes could be modi- fied if “good of the whole” pressures were applied. All in all, research efforts during World War II set the stage for an explosion of communication study in the years following the end of the war. Lazarsfeld and the Office of Radio Research studied how political advertise- ments during the presidential campaign of 1940 affected voters in Erie County, Ohio. This study, according to Lazarsfeld (1969: 330), was not originally intended to focus on voting habits but, instead, to test “a program of the Department of Agriculture, since its innovations made major changes in American behavior and … this Department … developed the most extensive use of the radio in support of its policies.” The Erie County study examined the changes in voters’ opinions over a period of several months, expecting to find that the media messages they were exposed to had a direct effect on their voting behavior. Instead of showing a direct effect, however, the analysis of the results showed that voting decisions were completely unrelated to the messages the audience had heard (Barton 2001; Jeřábek 2001; Rogers 1994). These findings completely contradicted the prevailing thought of the day. The study further showed that opinion leaders developed their ideas through a variety of sources that included the media, and then influenced the members
- 34. 20 William F. Eadie and Robin Goret of their community through their social interactions. The voters who Lazarsfeld interviewed inevitably pointed to these influential individuals as the source of their information and the main influence on their voting decisions. This finding led Lazarsfeld to propose that there was another level of communication other than the media (Lowery and DeFleur 1995), a process he called the two-step flow of communication. After Lazarsfeld’s large-scale case study demonstrated that media messages played only a small role in directly influencing election results, research in this area for a number of years focused on conditions where media messages would play more or less of a role than face-to-face influence in the formation of public opinion. It was not until McCombs and Shaw (1972) produced data causing the re- thinking of the small-effects paradigm that research shifted to what these authors dubbed “the agenda-setting function of media.” This function links press coverage with public ratings of importance with issues, and a study of the 1968 U. S. presi- dential election found a high correlation between these two items, given a three- week lag time. While these findings did not negate Lazarsfeld’s idea of two-step flow, they identified for the first time a powerful direct effect for media messages on public opinion. Rather than persuade people or tell them what to think, argued the researchers, media tell them what is important to think about. A companion theory, Cultivation (Gerbner 1973), argued that large effects from media could be generated based on the amount of time spent consuming media. Heavy users of media tended to distort perceptions of society to fit with media content to a far greater extent than did light users. For example, individuals who heavily consume news and news analysis from a particular point of view (e.g., in the U. S., Fox News or MSNBC) will be likely to distort news events to a greater extent than those who spent little to no time consuming content from these sta- tions. While Cultivation Theory had uses outside of public opinion research, it, too, was a crack in the formulation that media had but small effect on public opinion. In later developments, agenda-setting theorists demonstrated that media mes- sages also had the capability to influence how individuals think about topics. In particular, these theorists developed the concepts of “framing” and “priming” to describe this process. Framing refers to the means by which media messages are presented. Frames provide salience for particular aspects of the message that have been selected by its creator to shape it from a specific perspective (Entman 1993). So, a news story about a crime can be framed from the perspectives of the victim, the perpetrator, or the investigating police officer and the same details can yield different impressions of the event. Priming, on the other hand, relates to how media messages are constructed to indicate to audiences what elements are impor- tant to use in judging the value of an object. To provide an example, a news analysis is priming its readers when its author states that performance on main- taining a healthy national economy is the most important element for forming
- 35. Theories and models of communication: foundations and heritage 21 judgments about the performance of U. S. presidents when they run for re-election. Such an analysis may cause its readers to overlook other measures of presidential performance and focus only on economic viability. President Ronald Reagan, who was a master of priming rhetoric, famously asked American voters whether they were better off than four years previously as a cornerstone of his campaign for a second term. Americans agreed overwhelmingly that they were and returned Mr. Reagan to office in a landslide vote. The study of communication as a shaper of public opinion has focused pri- marily on means by which media messages influence the public’s perceptions of issues and events. Research on how mediated and face-to-face communication combine to change behavior has integrated public opinion research with other communication phenomena to produce promising means for promoting individual and social good. These models have been used primarily to create campaigns for the betterment of individual and public health (e.g., Cappella 2006; Donohew et al. 1998). 2 Communication as language use The turn of the twentieth century brought with it not only the investigation of stimulus and response as a direct cause of behavior but also an interest in philo- sophical quarters in how language is constructed and used. Early twentieth century interest in language use developed in both Europe and in the U.S. The study of language represented the variety of interests of the day, including interest in the nature of reality and the relationship of language to culture. For example, Ferdinand de Saussure, working in Europe, and Charles Sanders Peirce, working in the U. S., are credited with formulating the theory of semiotics. Saussure was a Professor of Linguistics at the University of Geneva in the first decade of the twentieth century. He posited that linguistics would eventually be incorporated into a then unheard of science called semiology (later named semiot- ics), the term being derived from the Greek word semeion. Saussure argued that language is a system made up of linguistic signs that join a concept and a sound image. The sign, according to Saussure (1916/2000), is a psychological construct with a number of distinct properties which include arbitrariness. Another approach to semiotics was undertaken by Roland Barthes who acted as an influential filter for Saussure’s teachings. In particular, Barthes extended Saussure, developing the dual nature of the sign for the study of nonverbal commu- nication, as well as language. In Barthes’s (1957) volume, Mythologies, the over- arching theme is that the majority of experiences a person has at a social or per- sonal level begin with the linguistic sign – media artifacts, identity, narrative, communication with others, and so on. But linguistic behavior as a structure of experience derives far less from personal exchange than with how language is
- 36. 22 William F. Eadie and Robin Goret conveyed to the personal level from the public level, where lies the locus of social control, including control over language itself (Barthes 2000). In fact, according to Barthes, linguistic signs with a forceful social meaning are not necessarily ‘clear’ but are rather ambiguous or deceptive in some way. Thus linguistic signs, as attributes of culture, lend themselves to ‘myth’, a ‘lan- guage’ devoted to the “decorative display of the what-goes-without-saying” which prevents the imposing “at the outset [of] a full meaning which it is impossible to distort” (Barthes 2000: 11, 132). Language may be unclear in a variety of ways, either because it is poetic or because it works by analogy. The key idea, for Barthes, is that language “lends itself to multiple contingencies” (132). Semiologists engage in this interpretive act, and it is up to the reader of myths to reveal their necessary function. That is because “in a language, the sign is arbitrary: nothing compels the acoustic image tree ‘naturally’ to mean the concept tree” (126). Instead, Barthes posited, there is a motivation for the sign to mean whatever it means from the habits and the traditions of the community of language users in which the word appears. Where language use is intent on signifying a cultural meaning there is undoubtedly intent to affect the psychological experience of that meaning (Barthes 2000). Motivation, Barthes argued, is essential “to the very duplicity of myth: myth plays on the analogy between meaning and form, there is no myth without moti- vated form” (126). Barthes cited the innumerable images that the media use to convey a social message, to imply, without directly pronouncing, the superiority of a Eurocentric and bourgeois worldview. The communicated image conforms to what Barthes termed the “very principle of myth: it transforms history into nature …[and] is not read as a motive, but as a reason” (129). In due course, he argued, values get conveyed with the authority of facts, all in the service of social control. Only when the receivers that would be recognized as decoders of language themselves effect language change is social control likely to shift. Thus, the “bour- geoisie hides the fact that it is the bourgeoisie and thereby produces myth; revolu- tion announces itself openly as revolution and thereby abolishes myth” (146). (See also Chapter 12, Cobley.) Somewhat in contrast to Barthes, interest in language use by Vygotsky (1971: originally published in 1934) and Ayer (1936) drew upon logical positivism and empiricism as a means of explaining the relationship of language to reality. Vygot- sky saw language development as a function of experience with one’s environment, using language to associate objects with thoughts and feelings. Ayer proposed the use of language as a means of verifying the logic of one’s environment. Language in itself is not verifiable, but it can be used to understand what may be verified empirically. A desire for empirical verification also pervaded the development of General Semantics, which started out as a theory of language use and became more a philosophy of communication than anything else. Begun by a Polish engineer
- 37. Theories and models of communication: foundations and heritage 23 named Alfred Korzybski (1933) and popularized in the U. S. by S. I. Hayakawa (1941), General Semantics began with the observation that language was not a logical system and ended by advocating for a series of devices designed to make communication based on language that was concrete, as opposed to abstract. Gen- eral Semanticists envisioned a communication system with as little ambiguity as possible so as to promote understanding and thereby reduce conflict, particularly conflict between nations. The proposed system was based on a set of tools that would continually remind language users to aim for the lowest possible level of abstraction in both speech and writing. Peirce’s (cf. 1878) work on the philosophical movement known as pragmatism influenced a number of U. S. scholars interested in language use. Among those were John Dewey, whose book, How We Think (1910), became the basis for teaching generations of students the basics of collective decision-making, and George Her- bert Mead, whose book, Mind, Self, and Society (1934, a posthumous rendering of his theory, based on lecture notes and working papers) became a basis for understanding how individuals interact with society through the use of signs and symbols. Mead and Dewey were colleagues at the University of Chicago for a time, and their interactions with each other and with colleagues were instrumental in developing the perspective that became known as the Chicago School of Sociology. Communication scholars eventually pursued with gusto Mead’s ideas about what was eventually called symbolic interactionism (Blumer 1969). Symbolic inter- actionism held that individual behavior was a function of the repertoire of roles available to an individual, as well as how that person diagnosed what role might be appropriate for a particular situation. Hart and Burks’s (1972) concept of rhetorical sensitivity provided an early example of the influence of symbolic interactionism in communication study, as these authors combined rhetorical message-generation principles with symbolic interaction’s emphasis on role-taking and adaptation. Eventually, symbolic interactionism gave way to social construction, as communi- cation scholars adapted the work of psychologist Kenneth Gergen (1992, 1999) for use in communication research. Social construction derived from the work of Ber- ger and Luckmann (1966), who argued that communication is dependent on inter- subjective meaning that operates at a societal level but is subject to re-negotiation within individual and group relationships. Kenneth Burke was a literary theorist whose ideas would prove to be highly influential in understanding of the rhetorical aspects of language use. Burke described language as a tool used by people to communicate and rationalize at a far deeper level than could be done by words themselves. Burke focused on the symbols people created to name things in his understanding of language. Accord- ing to Holland (1955) when rhetoricians analyzed speeches, they tended to look at three aspects – what was said, why it was said and how it was said. Burke however, would argue that Holland’s formulation did not go far enough and that a primary goal of criticism was to use “all [language instruments] that there is to use” (Burke,
- 38. 24 William F. Eadie and Robin Goret 1941: 23). For Burke, speeches were only one aspect of language instruments and he argued that a rhetoricians should not limit themselves to spoken text. Burke proposed the Dramatist Pentad Theory, which analyzes events through five essential elements: “what was done (act), when or where it was done (scene), who did it (agent), how he did it (agency), and why (purpose)” (Burke 1945: xv). He adapted his terms of analysis from the theater in order to account for motiva- tion, which he took to be a decisive category for the explanation of rhetorical events. Burke held that language is created hierarchically, that it reinforces hierar- chies, and that humans cling to hierarchies to bring order to their lives through symbolic actions. Language for Burke is always layered with emotion. Every word is layered with judgment, attitude and feelings, and Burke further argued that because of this complexity, language functions either to bring people together or to separate them. When people identify with the language and symbols that a speaker is using, this bringing-together process creates what Burke called “consub- stantiality.” Like many scholars of language use, Burke’s influence crossed disci- plines. Communication scholars poring over Burke’s work continue to find insights that reveal how language use not only communicates but can also influence com- municators. Of course, the study of language use overlaps with linguistics, including both its sub-fields of psycholinguistics and sociolinguistics. Yet, communication schol- arship tends to focus more on the pragmatics of language use, as well as the effects of such use, while linguistics often focuses more on structure and function of language. 3 Communication as information transmission Major strands of theory and research appeared in the U. S. following World War II. Most of them focused on information and transmission, or in other words, how to get a message from Point A to Point B in the most intact fashion possible. The key works associated with this perspective came from engineering, and the technologi- cal problems that drove the theorizing concerned the modernizing of the telephone system and the development of high speed computers that could process a great deal of information in a short span of time. Two books stood out in particular: Claude Shannon and Warren Weaver’s (1949) The Mathematical Theory of Commu- nication and Norbert Wiener’s (1948) Cybernetics. Shannon and Weaver developed a theory that defined information as the reduction of uncertainty, and their pri- mary concern revolved around how much “noise” (pure uncertainty) in any trans- mission could be tolerated before the message would be transmitted inaccurately. Wiener’s work described the reduction of uncertainty in systems through feedback that would indicate a change of course was needed. Wiener’s scholarship on the control of systems was instrumental in developing computers, which were popu-
- 39. Theories and models of communication: foundations and heritage 25 larly known as “thinking machines.” Scholars who built on Shannon and Wiener’s work attempted to model communication based on transmission of information, moderated by feedback. Some scholars (cf. Dupuy 2000) believed that these theo- ries could be used to model thought, about which little was then known. Indeed, a great deal of theory and research in communication and media based itself on the transmission model and continued to do so after the appearance of information theory and cybernetics. Two post-World War II research programs illus- trated this approach. The first was the Yale Communication and Attitude Change Program, directed by Carl Hovland. Hovland had been one of the scholars who worked on propaganda research for the Federal government during World War II, and after the war he focused his efforts on understanding how people were influ- enced by other people and their messages to change their attitudes. According to McGuire’s (1996) review of that period, Hovland succeeded because he was able to attract top-notch faculty and graduate students to work on the project and because his management style allowed for creativity of theory development while still keep- ing research focused on the overriding goal. Hovland’s efforts made attitude change the major topic for social psychological research during the 1950s and 1960s. The second came via the leadership of Wilbur Schramm, another veteran of the Federal government’s propaganda research program. Schramm moved to Wash- ington, DC, from the University of Iowa, where he was head of the famed Iowa Writers’ Workshop. When the propaganda project ended, Schramm wanted to return to Iowa, but his position with the Writers’ Workshop had been filled. Instead, Iowa asked Schramm to head its journalism school, and Schramm accepted the position with the condition that he be allowed to start an institute for communication research. Schramm’s institute spurred the beginning of the field of journalism’s association with mass communication scholarship, as opposed to scholarship about journalism itself. Under Schramm’s tutelage, Iowa scholars and others attempted to take the theoretical work from information theory and social psychology and apply it more directly to understanding communication phenom- ena. Journalism scholars were joined in this effort by scholars from the field of speech who were energized both by Kurt Lewin’s work on group dynamics and the Yale Group’s scholarship on individual credibility in promoting attitude change. Schramm became a proselytizer for communication scholarship, and he began institutes at the University of Illinois and Stanford before affiliating with an insti- tute in Hawaii after retirement (Rogers 1994). Such models of communication as transmission began to break down in the 1960s. David Berlo’s (1960) book, The Process of Communication, for example, pre- sented what was then a traditionally linear transmission model of information flow but added the idea that communication was dynamic and cyclical and that research efforts to measure simple effects would ultimately fall short. Berlo urged scholars to account for process in their research, but he did not provide a clear means for so doing. It would take some years before scholars began to devise ways
- 40. 26 William F. Eadie and Robin Goret to measure communication as interaction and thus to downplay effects research. Indeed, measuring process can be a complex task, as illustrated by Luhmann’s (2000) mathematical theorizing about the cyclic nature of media news. In media research, the transmission model found continued life as part of research using Social Learning Theory and later, Social Cognitive Theory (Bandura 1986). Research conducted under the theme of learning the audience’s uses and gratifications of media (Blumler and Katz 1974) later found the transmission model amenable for some time before succumbing to criticism that audiences were more active than the approach gave them credit (e.g., Reinhard and Dervin 2009). But, the information transmission approach was not only about movement of data from one point to another. Shannon and Weaver’s (1949) theory, for example, also focused on how information functioned either to increase or decrease entropy, or the level of uncertainty within a system. As Wiener (1948) noted, uncertainty is present in every system and is a healthy element, causing the system to self-correct via the use of negative feedback. Two different theorists applied this principle to specific situations, creating examples of a turn away from the development of grand theories of communication and moving toward more contained theories that provided more focused opportunities for testing. The first was Berger’s Uncertainty Reduction Theory (Berger and Calabrese 1975), which was focused on communica- tion between individuals who were just beginning a relationship. Drawing on infor- mation theory’s central tenet that individuals process information for the purpose of reducing uncertainty, Berger and Calabrese laid out a set of variables such as amount of verbal communication, nonverbal affiliative expressiveness, informa- tion-seeking behavior, intimacy content of messages, reciprocity of information sharing, perceived similarity and liking between communicators, and degree of perceived shared communication networks. From these variables, the authors drew eight axioms and twenty-one theorems that served as the basis for a program of research that has continued through the present day. A second use of the uncertainty principle emerged from the work of Karl Weick. An organizational psychologist, Weick (1969) proposed that organizing is a process that involves reducing uncertainty through the negotiation of organizational goals and routines. While previous theorists had assumed that organizations were formed to achieve goals, Weick contended that organizational goals evolved out of interaction among the organization’s members. Weick called the process of individ- ual negotiation with the organization and its members “sensemaking,” and he proposed that organizations were loosely-coupled systems where collective mean- ings of messages and actions evolved over time. Weick’s notions were radical in that they ignored organizational hierarchies in favor of the power of informal net- works to define and influence collective thought and actions. Communication scholars eagerly embraced Weick’s ideas about organizations and have used his sensemaking principle as a means of studying organizational culture, oftentimes employing qualitative data such as stories (e.g., Smircich and Calás 1987).
- 41. Theories and models of communication: foundations and heritage 27 The information transmission model remains a dominant one in communica- tion scholarship, though its nature has become more process-like and less linear over time. 4 Communication as developer of relationships Relational communication scholarship emerged from a variety of sources, includ- ing anthropology, social and clinical psychology, social work and family studies, and systems analysis. It is likely that scholars from a number of disciplines influ- enced each other as common problems overlapped. For example, Schramm (1997), who was working on propaganda research during World War II in Washington, DC, shared a carpool with anthropologist Margaret Mead, who was working on conserv- ing food for the war effort and whose program funded Kurt Lewin’s (1948) work on using groups to solidify cooperation from homemakers to use what they might consider to be “inferior” cuts of meat in preparing meals for their families. Mead, in turn, was married to Gregory Bateson, whose work on family systems in the post-World War II era would develop the idea that double binds (communications where meaning was made deliberately unclear) were a basis for relational pathol- ogy (Bateson, et al. 1956). Behavioral researchers approached relationships as a matter of perception (e.g., Heider 1946; Thibaut and Kelley 1959), while clinical psychologists defined relational intimacy in terms of degrees of authenticity (e.g., Buber 1947; Rogers 1961) and degree to which being in relationship with others allowed individuals to self-actualize (Maslow 1943) (see also Chapter 14, Bangerter and Mayor). In fact, Peters (1999), in his intellectual history of the idea of communication, argued that all curiosity about communication arises from a desire for connection at a number of levels: another’s soul and/or intellect, which we cannot directly experience; those entities (such as plants and animals) that do not use symbols; and connec- tion that is distinguished by authenticity that the participants do experience. The two groups often found themselves at cross-purposes, and they disagreed substan- tially about the nature of the phenomena they were studying. Building on Bateson’s work, Watzlawick et al. (1967) devised the basis of a formal theory of relational communication. In particular, the group’s five axioms became the cornerstone of a number of research programs: (1) “one cannot not communicate”; (2) “every communication has a content and relationship aspect such that the latter classifies the former and is therefore a meta-communication”; (3) “the nature of a relationship is dependent on the punctuation of the partners’ communication procedures”; (4) “human communication involves both digital and analogic modalities”; and (5) “inter-human communication procedures are either symmetric or complementary, depending on whether the relationship of the part- ners is based on differences or parity”. Dubbed “the interactional view,” Watzlaw-
- 42. 28 William F. Eadie and Robin Goret ick et al.’s work led the study of communication in relationships away from both competing emphases: variable analysis and psychic connection. The end of variable analysis did not spell the end of quantitative approaches to relational communication, however. Instead, quantitative research sought to blend verbal and nonverbal elements of communication behavior so as to demonstrate how those elements combine to produce interactive meaning. An exemplar of such an approach, Burgoon’s (1978) Expectancy Violations Theory, proved to be a model of the genre. Burgoon revised her theory often and sometimes substantially based on the data she collected (c.f., Burgoon and Hale 1988), and the result of persist- ence and a willingness to reinterpret her findings has made the theory one of the most respected and robust of its type. Relational communication has also been studied qualitatively, through inter- views, personal narratives, and ethnographic approaches. An exemplar of a theory emerging from such study is Relational Dialectics Theory, which was developed by Leslie Baxter and her associates (e.g., Baxter and Montgomery 1996). Derived from the work of philosopher Mikhail Bakhtin (1986), the theory proposed that relation- ships are developed out of the push and pull of interaction. Some of the contradic- tory dynamics that the theory has studied are: (1) autonomy vs. connectedness (i.e., how much “I” and how much “we” are needed by relational partners); (2) favoritism vs. impartiality (i.e., how much is each partner treated “fairly,” as opposed to how much each partner is valued as “special”); (3) openness vs. closed- ness (i.e., how much information is disclosed between partners, as opposed to how much information is kept private); (4) novelty vs. predictability (i.e., how much the relationship feels exciting and new, as opposed to how much it feels comforta- ble and old); and (5) instrumentality vs. affection (i.e., how much continuing the relationship is based on tangible rewards, as opposed to how much continuing the relationship is based on emotional rewards). Relational communication replaced the former “interpersonal communication” as the designator for communication in face-to-face settings. The term implies that it is the relationship that is being studied, not the face-to-face context, and this subtle change in focus has made a great deal of difference in how theorizing in this approach to communication study has proceeded. 5 Communication as definer, interpreter, and critic of culture The early works of the Frankfurt School, specifically critical theory, laid the foun- dation that led toward one of several paradigm shifts in communication theory during the post-World War II era. According to Jay (1973, 1980), Rogers (1994), Tar (1977) and others, critical theory is the term that refers to a specific tradition of
- 43. Theories and models of communication: foundations and heritage 29 thought that originated with Herbert Marcuse, Theodor Adorno, Max Horkheimer, and Walter Benjamin in the 1930s at the Frankfurt School and the Institute of Social Research in Germany. This theory synthesizes ideas advanced by Karl Marx and Sigmund Freud and positions media as having the potential to advance the agenda of the bourgeois while controlling the proletariat (Jay 1973; Tar 1977). Cel- ikates (2006) posited that critical theory makes it possible for one to understand what is really happening in social reality and to explain these actions in terms of such constructs as socioeconomic structures and who in society has the power. Critical theory, Celikates (2006) further argued, questions and analyzes media, the production of media, and its agents (see also Chapter 18, Schrøder). Not all critical models of communication followed the Frankfurt School line. In the early 1960s at the University of Birmingham in the United Kingdom, a group of scholars founded the Centre for Contemporary Cultural Studies (producing a body of work that later became synonymous with British Cultural Studies) because they had a desire to understand the changes in post-war British society within the structure of “a long retrospective historical glance” (Hall, 1992: 16). Hall (1980) argued that Cul- tural Studies “defines ‘culture’ as both the meanings and values which arise amongst distinctive social groups and classes on the basis of their given historical conditions and relationships, through which they ‘handle’ and respond to the conditions of exis- tence” (63). An essential element of the new paradigm was to redefine and refocus the meaning of communication itself. Hall (1992) cited the practice of analyzing commu- nication as similar to a circle of activity. The emerging idea was to think of communi- cation as “structure produced and sustained through the articulation of linked but distinctive moments – production, circulation, distribution/consumption, reproduc- tion” (128). This idea came to be known as structuralism (not to be confused with the same term applied to anthropology and linguistics) and had its roots not just in Marx- ist theory but in early semiotic theory, particularly the code-semiotics of Eco (Hall, 1980) (see also Chapter 12, Cobley). For Hall, though, there were inherent problems in the idea of structuralism such that the content of ideas gives way to patterns of ideas that may be contained in a communication, as well as the means or conventions, whether literary, linguistic, or social, by which the ideas are encoded and function toward making meaning. The encoding of a communication event is only part of the process of commu- nication itself, carrying no essential meaning without an audience (or receiver) to decode what the meaning is and, by decoding the message, the audience con- structs the meaning. Hall (1992) provided the example of a TV news broadcast, which has an impact on the society in which the encoded message is transmitted only when the meanings are decoded. Drawing on the work of sociologist Frank Parkin, as well as semiotician Umberto Eco, Hall posited that there were three types of readings of meanings of a message when it was decoded. The dominant or preferred reading is produced by those whose status favors the preferred read- ings and therefore do not question the dominant ideology; the negotiated readings
- 44. 30 William F. Eadie and Robin Goret are produced by those who interpret the preferred reading as it is aligned with their societal status; and the oppositional readings are produced by those whose social status puts them in direct conflict with the dominant ideology. Embedded in the foundation of British Cultural Studies is the work of Antonio Gramsci, specifically Gramsci’s extension of the Marxist concept of hegemony. Gramsci argued that the bourgeois retained power not just through political, eco- nomic or violent control of the masses but ideologically through a cultural power that conveyed that the values of the “haves” are common sense values for all of society. If the working class believed they have the same values as the “haves” in society, they would maintain the status quo and not work to change society for the betterment of the working class. Gramsci also noted that “common sense is not something rigid and immobile, but is continually transforming itself” (Hall 1982: 73). Stuart Hall and the British Centre for Cultural Studies applied Gramsci’s theory of cultural hegemony to the examination of racial representations in the media by illustrating racist stereotypes that Hall called the “grammar of race” embedded in early films of the twentieth century (Hall 1995: 21) (see also Chap- ter 18, Schrøder). Jürgen Habermas, a student of Theodor Adorno, added further to the foundation laid by the Frankfurt School and the British Centre for Contemporary Cultural Studies. During his tenure at the Frankfurt School, Habermas focused his research on how a new public sphere materialized during both the age of Enlightenment and the French Revolution in Europe and the American Revolution in the United States and how this new public sphere encouraged political discourse and closely examined language, meaning, and understanding during political discourse (Habermas 1973, 1974, 1984, 1989; Jay 1973; Kellner 2000; Wiggerhaus 1994). Habermas (1974) posited that access to the public sphere was granted to all citizens and that the dialogue about political power did not always exist, it “grew out of a specific phase of bourgeois society and could enter into the order of the bourgeois constitutional state only as a result of a particular constellation of interests” (50). Using the U.S. wars in both Vietnam and the Gulf Wars as examples, Habermas developed the view that public opinion and understanding of the wars were primarily shaped by “the demonstrative rationality of the military planning, and the unparalleled presence of the media” (Habermas, 1994: 6). The “encoding” objectives of those in power were, in Habermas’ view, involved in managing how much information and precisely what information to dis- pense to the general public in a way that was meant to influence public opinion and to install a “staged reality” that existed not just for the general public, but for the “mediators” of public information as well. The act of installing a staged reality, Haber- mas argued, transformed media from a place that aided rational discourse to one that limited such discourse to what media corporations wished to discuss (see also Chap- ter 5, Lanigan). Habermas also examined early theories of semantics and put forth the theory of meaning. He argued that the “meaning of sentences, the understanding of sentence meanings cannot be separated from language’s interest in relation to the
- 45. Theories and models of communication: foundations and heritage 31 validity of statements” (1984: 276). Habermas further argued that by understanding the validity of statements, a communicative action occurs. Habermas posited that communicative action occurs when at least two parties “reach an understanding about the action situation and their plans of action in order to coordinate their actions by way of agreement” (86). Besides the cultural studies approach, which often took societal critique as a given (see also Chapter 18, Schrøder), theorizing and scholarship have also been devoted to understanding communication across cultures or across groups within cultures. Cultural anthropologist Edward T. Hall (1959, 1966) provided the genesis of this scholarship with his sweeping ideas of types of culture (high context, low context), space (Hall introduced the concept of proxemics and documented how cultures vary in their use of space), and time (Hall originated the ideas of polychro- mic and monochromic time). Much of the theorizing in this area of study built on either the information transmission or the relational approach (c. f., Gudykunst 2005), but one attempt to develop a unique cultural perspective on communication has come from the work of Guo Ming Chen. Chen, who splits his time between the University of Rhode Island and the South China University of Technology, has outlined in a series of articles (Chen 2001, 2002a, 2002b, 2002c, 2004, 2005, 2006) a vision of communication based in several Asian concepts: harmony, the polarity of the yin and the yang, the Tao, the I Ching, and Confucian spirituality. Assuming Chen’s formulation is developed further through research, it could provide a new direction for theorizing about how communication is culture-specific. 6 Concluding remarks In 1999, Robert T. Craig summarized different theoretical strands in communication scholarship into seven “traditions:” rhetorical, semiotic, phenomenological, cyber- netic, sociopsychological, sociocultural, and critical. Craig (1999) defined the rhe- torical tradition as considering communication to be a practical art; the semiotic tradition as considering communication to be intersubjective mediation via signs; the phenomenological tradition as considering communication to be the capacity of experiencing otherness through authentic dialogue; the cybernetic tradition as considering communication to be synonymous with information processing; the sociopsychological tradition as considering communication to be expression, inter- action and influence; the sociocultural tradition as considering communication to be the means by which the social order may be (re)produced; and the critical tradition as considering communication to be discursive reflection, particularly on hegemonic ideological forces and how these might be critiqued. Each of these traditions combines ontology and epistemology differently (Anderson and Baym 2004), making communication theory truly a “big tent” encompassing social scien- ces, humanities, and arts (see also Chapter 3, Craig).
- 46. 32 William F. Eadie and Robin Goret Craig (1999) worried that scholars adhering to each of his traditions were suffi- ciently different from each other that they potentially could not engage in dialogue about what issues were important to communication as a discipline. Disciplinary dialogue, Craig argued, is essential to growth, development, and ultimately to dis- ciplinary health. While we have defined the major intellectual strands of communi- cation in a slightly different manner than did Craig, we do not have the same worries. There may be no such thing as COMMUNICATION THEORY, but there may be many communication theories, each proceeding from a different understanding of communication phenomena and each contributing to scholarship proceeding from that understanding. There may be quarrels about which of these understand- ings is “correct” (or, more likely, which might be considered “incorrect” or “inad- equate”), but ultimately we find commonality through appreciating the variety of different approaches and the scholarship they have produced. “Communication” may turn out to be the wrong term to define what we are studying, but for the moment it is good enough. Further reading Anderson, James A. & Geoffrey Baym. 2004. Philosophies and philosophic issues in communication, 1994–2004. Journal of Communication 54. 589–615. doi:10.1093/joc/ 54.4.589 Craig, Robert T. 1999. Communication theory as a field. Communication Theory 9. 117–161. doi:10.1111/j.1468–2885.1999.tb00355.x Eadie, William F. 2011. Stories we tell: Fragmentation and convergence in communication disciplinary history. The Review of Communication 11. 161–176. Peters, John Durham. 1999. Speaking into the air: A history of the idea of communication. Chicago, London: University of Chicago Press Rogers, Everett M. 1994. A history of communication study: A biographical approach. New York: Free Press. References Anderson, J. A. & G. Baym. 2004. Philosophies and philosophic issues in communication, 1994–2004. Journal of Communication 54. 589–615. doi:10.1093/joc/54.4.589 Ayer, A. J. 1936. Language, truth and logic. London: Victor Gollancz [Reprinted by Penguin Books, 1990]. Bakhtin, M. M. 1986. Speech genres and other late essays, McGee, Vern W. (trans.). Austin, TX: University of Texas Press. Bandura, A. 1986. Social foundations of thought and action: A social cognitive theory. Englewood Cliffs, NJ: Prentice-Hall. Barthes, R. 2000. Mythologies, Lavers, A. (trans.). New York: Hill and Wang. [Originally published 1957].
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- 51. I Theories and models
- 53. Robert T. Craig 3 Constructing theories in communication research Abstract: Diverse approaches to theory construction are distinguished by different metatheoretical assumptions of epistemology, ontology, axiology and praxeology. Two broad approaches are the empirical-scientific and critical-interpretive. A scien- tific theory is a logically connected set of abstract statements from which empiri- cally testable hypotheses and explanations can be derived. Models and paradigms are distinguished from theories. Several approaches to scientific explanation and theory development are discussed. Critical-interpretive approaches represent a con- vergence of humanities and social science. Interpretive approaches emphasize the heuristic function of theory, while critical approaches emphasize social change. Postmodern critical-interpretive theory intervenes in societal discourses to decon- struct or reconstruct social practices. Keywords: Metatheory, epistemology, ontology, axiology, praxeology, empirical- scientific approaches, scientific explanation, models and paradigms, critical-inter- pretive approaches, practical theory 1 Introduction This chapter presents an overview of theory construction in communication research. The diversity of ideas in the field makes this a challenging task. Not only are there many theories about communication and media, those theories represent radically different intellectual styles, reflecting different assumptions about the object of study, the nature of theory and the process of inquiry in general (Craig 1993, 1999). Indeed, the very idea that theories are discrete conceptual objects “constructed” in some systematic way makes more sense in some views of commu- nication theory than in others. The diversity of theories in communication research has been influenced by recent interdisciplinary trends; however, it is not only a product of recent develop- ments. Theories relevant to communication and media sprang up independently across the humanities and social sciences before a distinct field of communication research took shape in the second half of the twentieth century. Rather than appearing all at once ex nihilo or branching off from a single limb of the academic tree, communication research developed lines of inquiry from many sources, and even now the field continues to grow, in part, by incorporating new interdisciplin- ary areas with their sometimes distinct theoretical approaches.
- 54. 40 Robert T. Craig The fragmented state of the field calls for broad awareness and careful reflec- tion on practices of theory construction. This chapter introduces metatheory as an effort to achieve a critical understanding of the diversity of theories in the field and the fundamental choices involved in constructing theories. Following a general introduction to metatheory, two current issues for communication theory are dis- cussed, and diverse methods of theory construction are sketched within two broad approaches. 2 Metatheory Metatheory is a branch of theory that articulates and critiques the assumptions underlying particular theories or kinds of theory. Every work of theory relies on assumptions, some of which may be stated explicitly in the theory but most of which are usually left implicit. Following Anderson (1996: 2; see also: Anderson and Baym 2004; Craig 2009; Craig and Müller 2007: 55–62; cf. Fiske and Shweder 1986: 3), four kinds of metatheoretical assumptions can be distinguished: assump- tions about fundamental characteristics of the objects that are theorized (ontol- ogy), about the basis for claims regarding a theory’s truth or validity (epistemol- ogy), about normative practices for generating, presenting and using theories (praxeology), and about the values that determine the worth of a theory (axiology). Approaches to theory construction that are often loosely described as “episte- mologies” can be shown to differ complexly across all types of metatheoretical assumptions (Craig 2009). As a matter of convenience, this chapter distinguishes two broad approaches: empirical-scientific and critical-interpretive, each of which spans many differences. However, there can be no single, all-purpose scheme for classifying theories. Theories can be distinguished and grouped to highlight par- ticular metatheoretical issues important for theory construction. Two of those important issues for communication theory will be introduced before surveying the major approaches to theory construction. The first issue concerns communication’s ontological status as a process of information transmission or as the social consti- tution of meaning. The second issue concerns communication theory’s epistemo- logical status as either universal or culturally specific. 2.1 An ontological issue: what is a communication theory? Communication is still commonly understood as a process in which some content (thought, information) is transmitted from a sender through a medium or channel to a receiver. Although a transmitted message may be called “a communication,” it acquires that status only by virtue of being transmitted. In this common view, communication can also refer to the activity of communicating, which consists
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- 56. CHAPTER VIII. THE CHEMICAL CONSTITUENTS OF SKIN. The chemistry of the various constituents of skin is still very imperfectly understood, but Beilstein, in his great handbook of organic chemistry, places gelatin, albumens and keratins in the “aromatic” series, and implies therefore that they contain the “benzene” ring. It is at least certain that all are very complex. The epidermis structures belong to the class of keratins, which are closely related to coagulated albumin; while the white fibres of the corium (or true skin) are either identical with gelatin, or only differ from it in their molecular condition or degree of hydration. This gelatinous tissue constitutes the bulk of the corium, but it also contains albumen as a constituent of the lymph and blood which supply its nourishment, keratins in the epithelial structures of the blood and lymph vessels, and “yellow fibres,” which are perhaps allied to the keratins, but which cannot well be isolated for analysis. The white connective tissue of the corium is converted into gelatin (glutin) by boiling with water. Owing to the impossibility of obtaining unaltered hide-fibre free from the other constituents, and still more to that of deciding to what point it should be dried to remove uncombined water, it is impossible to prove by analysis whether its composition is identical with that of glutin; but as the white fibre constitutes by far the largest part of the corium, and the other constituents do not differ largely from it in their percentage composition, an analysis of carefully purified corium is practically identical with that of the actual fibre. The following analyses of hide and gelatin are therefore of interest. The analyses of Von Schroeder and Paessler[22] are of special importance as being the average of a large number of separate determinations. Their nitrogen determinations are by Kjeldahl’s method. Small amounts of ash and traces of sulphur are neglected, and probably included in the O, which is obtained by difference.
- 57. [22] Ding. Polyt. Journ., 1893, cclxxxvii. pp. 258, 283, 300. Analyses of Purified Corium. Analyst. Material. C H N O S Stohmann and Langbein .. 49·9 5·8 18·0 26·0 0·3 Müntz Ox-hide 51·8 6·7 18·3 23·2 .. Von Schroeder and Paessler Ox, calf, horse, camel, pig, rhinoceros 50·2 6·4 17·8 25·4 .. „ Goat and deer 50·3 6·4 17·4 25·9 .. „ Sheep and dog 50·2 6·5 17·0 26·3 .. „ Cat 51·1 6·5 17·1 25·3 .. Analyses of Gelatin (free from Ash). Analyst. C H N O Von Schroeder and Paessler 51·2 6·5 18·1 24·2 Mulder 50·1 6·6 18·3 25·0 Fremy 50·0 6·5 17·5 26·0 Schützenberger 50·0 6·7 18·3 25·0 Chittenden and Solly[23] 49·4 6·8 18·0 25·1 [23] Contained also 0·7 sulphur. Journ. Physiol., xii. p. 23. It will be noted that the above analyses of skin differ more widely among themselves than their average does from that of the gelatin analyses, though on the whole the nitrogen is somewhat higher in the latter. The molecular weight of gelatin must be very high,[24] and any empirical formula founded on ultimate analysis therefore quite hypothetical. Bleunard,[25] Schützenberger and Bourgois,[26] and Hofmeister agree on the formula C76H124N24O29, which leads to the following percentage composition:— per cent. C76 = 912 = 49·7 H124 = 124 = 6·8 N24 = 336 = 18·3 O29 = 464 = 25·2 1836 100·0 [24] Paal (Berichte D. Ch. Ges., xxv. (1892) pp. 1202-36, and Ch. Soc. Abst., 1892, pp. 895-7) calculates a molecular weight of about 900 from
- 58. physical (freezing, boiling point) methods. [25] Annales de Chimie [5] xxvi. p. 18. [26] Compt. Rend., lxxxii. pp. 262-4. The addition of a molecule of water would make a difference in the percentage composition indicated by these formulæ which would be less than their probable experimental error, and the change may therefore be one of hydration. Gelatin certainly contains both carboxyl and amido-groups, and is capable of combining with both acids and alkalies (see p. 84). Reimer[27] obtained what he supposed to be pure unaltered fibre- substance by digestion of purified hide with 1⁄2 per cent. acetic acid for many days and subsequent neutralisation. His analysis showed C = 48·45 per cent., H = 6·66 per cent., N = 18·45 per cent., O = 26·44 per cent., thus deviating considerably from direct analysis of unaltered skin. It is obvious that little weight can be placed on this result, Reimer’s precipitate being probably a mere decomposition product. [27] Ding. Polyt., ccv. p. 164. Hofmeister[28] notes that on heating gelatin it loses water and forms an anhydride which he considers identical with collagen or hide-fibre. When gelatin is dried at a temperature of 130° C. it becomes incapable of solution in water, even at boiling temperature, and can only be dissolved by heating under pressure. It is certain that collagen (hide- fibre, ossein) is less easily soluble in hot water than ordinary gelatin. [28] Bied. Centr., 1880, p. 772. So far as our present knowledge goes, we may regard hide-fibre as merely an organised and perhaps dehydrated gelatin. Gelatin or glutin (not to be confounded with the gluten of cereals), when pure and dry is a colourless, transparent solid of horny toughness and of sp. gr. 1·3. It begins to melt about 140° C., at the same time undergoing decomposition. It is insoluble in hydrocarbons, in ether, or in strong alcohol. In cold water it swells to a transparent jelly, absorbing several times its weight of water, but does not dissolve. In hot water it is soluble, but a solution containing even 1 per cent. of good gelatin sets to a weak jelly on cooling. Gelatin jellies melt at temperatures which vary considerably with the quality or freedom from degradation products, but which within pretty wide limits (5-10 per
- 59. cent.) are little affected by the concentration. A 10 per cent. solution of best hard gelatin melts about 38° C., while low glue may fail to set at 15° C. A useful technical test for the setting power of gelatin, based on this fact, consists in placing an angular fragment of the jelly in a small tube attached to a thermometer, and stirring in a beaker of water, which is slowly heated till the jelly melts, when the temperature is noted. The exact point is perhaps more easily seen if the tube is drawn to a conical point. The jelly may also be allowed to set in capillary tubes open at the bottom, and the moment noted when water rises into the tube. The temperature of fusion is raised by the addition of formaldehyde, salts of chromium, alumina and ferric salts, which produce a tanning effect, and in a less degree by sulphates, tartrates, acetates, some other salts, and diminished by iodides, bromides, chlorides and nitrates.[29] Solutions of gelatin too weak or too warm to gelatinise possess considerable viscosity. Gelatin may therefore be estimated, in the absence of other viscous matters, by the viscosimeter, an instrument which measures the time taken by a liquid in flowing through a capillary tube.[30] The firmness of a jelly, which is often important for commercial purposes, is frequently measured by Lipowitz’s method, in which a slightly convex disc, conveniently of exactly 1 cm. diameter, and cemented to the bottom of a thistle-head funnel tube, is loaded gradually with mercury till it sinks in the jelly. The jelly (5 or 10 per cent.) should be allowed to set some hours before the test is made. [29] See Pascheles, ‘Versuche über Quellung,’ Archiv für ges. Path., Bd. 71. [30] See Prollius, Ding. Polyt. Journ., ccxlix. p. 425, who employs a 1 per cent. solution; also Stützer, Zeit. Ann. Ch., xxxi. pp. 501-15. Solutions of gelatin from skin and bone are powerfully lævorotatory to polarised light. At 30° C. (A)D = -130°, but temperature and the reaction of the solution have much influence on the value found. Gelatin is precipitated from aqueous solution by the addition of strong alcohol and concentrated solutions of ammonium sulphate and some other salts. Many other colloid bodies such as dextrin and gums behave similarly. In the absence of these substances, precipitation by alcohol may be utilised for the technical analysis of gelatins and glues, printers’ roller compositions and gelatin confectionery. 25 c.c. of the gelatinous solution, which is preferably of about 10 per cent., is placed
- 60. in a small beaker tared together with a glass stirring rod, and thrice its volume of absolute alcohol added. On stirring, the gelatin sets firmly on the rod and sides of the beaker, and may be washed with dilute alcohol or even with cold water, dried and weighed. A very pure French gelatin gave 98·6 per cent., while a common bone-glue only yielded about 60 per cent. precipitate. Absolute alcohol withdraws water from gelatin- jelly, leaving a horny mass. Gelatin may also be precipitated completely by saturating its solution with sodium chloride, and then acidifying slightly with sulphuric or hydrochloric acid; and masses of jelly become hardened in acidified salt solution as in alcohol, though a neutral solution has little effect. The cause of this is difficult of explanation, but its bearing on the pickling of sheep-skins (p. 89) and the production of white leather (p. 186) is obvious. Decompositions.—When aqueous solutions of gelatin are heated under pressure, or in presence of glycerin and other bodies which raise the boiling-point, or more slowly at lower temperatures, they gradually lose the power of gelatinising on cooling, the gelatin being converted into modifications soluble in cold water, but still capable of being precipitated by tannin. Hofmeister[31] states that the gelatin takes up 3 molecules water and is split up into hemicollin, soluble in alcohol and not precipitated by platinic chloride solution; and semiglutin, insoluble in alcohol and precipitated by platinic chloride solution. Both are precipitated by mercuric chloride. Dry gelatin is soluble in glycerin at high temperatures, but probably suffers a similar change. Hence high temperatures and long-continued heating must be avoided in gelatin manufacture; and in making printers’ roller compositions, which are mixtures of gelatin and glycerin, the gelatin must be swollen with water and melted at a low temperature with the glycerin. [31] Bied. Centr., 1880, p. 772, and Ch. Soc. Abs., 1881, p. 294. Gelatin is also converted into soluble forms (peptones), perhaps identical with the above, by the action of heat in presence of dilute acids and alkalies. These, like gelatin, are precipitated by tannin and by metaphosphoric acid.[32] Heated for longer periods or to higher temperatures with aqueous solutions of the caustic alkalies, baryta, or lime, gelatin is gradually broken down into simpler and simpler products, ending in nitrogen or ammonia, water and carbonic acid.
- 61. Among the intermediate products may be mentioned various acids of the amido-acetic series, as amido-acetic (glycocine, glycocoll), amido- propionic (alanine), and amido-caproic (leucine); and of the amido- succinic series (amido-succinic = aspartic acid).[33] [32] Lorenz, Pflüger’s Arch., xlvii. pp. 189-95; Journ. Chem. Soc., 1891, A. p. 477. [33] Compare Schützenberger, Comptes Rend., cii. pp. 1296-9; Journ. Chem. Soc., 1886, A. p. 818. Treatment with acids produces very similar effects. The first products are soluble peptones. Paal[34] on treating 100 parts of gelatin on the water-bath with 160 parts water and 40 parts concentrated HCl till the product was soluble in absolute alcohol, obtained, on purification, a white hygroscopic mass of peptone salts containing 10-12 per cent. of hydrochloric acid.[35] [34] Berichte, xxv. pp. 1202-36; Journ. Chem. Soc., 1892, A. p. 895. [35] See also Buchner and Curtius, Ber., xix. pp. 850-9; Journ. Chem. Soc., 1886, A. p. 635. The products of digestion of gelatin with gastric and pancreatic juice are peptones which do not differ materially from gelatin in ultimate composition, and the action is probably mainly hydrolytic.[36] [36] Chittenden and Solly, Journ. Chem. Soc., 1891, A. p. 849. The earlier products of putrefaction are very similar. Many bacteria have the power of liquefying gelatin-jelly. This has been shown by Brunton and McFadyen[37] to be due not to the direct action of the bacteria, but to a soluble zymase secreted by them which peptonises the gelatin. Its action is favoured by an alkaline condition, and destroyed by a temperature of 100° C.[38] As putrefaction progresses, the solution becomes very acid from the formation of butyric acid, and later on ammonia and amido-acids are formed. [37] R. S. Proc., xlvi. pp. 542-53. [38] Compare pp. 17, 171; also Ch. Zeit., 1895, p. 1487. Fahrion,[39] starting with the idea that albuminoids and gelatin were condensation products of a lactone character (L.I.L.B. p. 185), and that they might, like lactones, be depolymerised by saponification, digested these bodies with alcoholic soda till they were dissolved, and on
- 62. neutralising the solution with hydrochloric acid, of which the excess was driven off by repeated evaporation, and removing the sodium chloride by treatment with alcohol, obtained in each case bodies of acid reaction, which from their composition he supposed to be identical with Schützenberger’s proteic acid, C8H14N2O4, which is soluble in water and alcohol, insoluble in ether and petroleum, uncrystallisable, and forming uncrystallisable salts. Fahrion suggested that the nitrogenous character which Eitner attributed to his “dégras-former” (p. 370) was probably due to contamination by this body; and that its formation might be utilised in the analysis of leather and other proteid bodies. These products have since been further investigated by Prof. Paal and Dr. Schilling,[40] who show that they contain hydrochloric acid, to which their acid reaction is due, and that they are identical with the peptone salts previously obtained by Prof. Paal (v. s.) by digestion of proteids with hydrochloric acid. The free peptones are strongly basic. [39] Ch. Zeit., 1895, p. 1000. [40] Ch. Zeit., 1895, p. 1487. By dry distillation of gelatin a mixture of pyrrol and pyridin bases are produced. This is commercially obtained by the distillation of bones, and is known as “bone oil,” or “Dippel’s animal oil.” Pyrrol, C4H5N, resembles phloroglucol in giving a purple-red colour to fir wood moistened with hydrochloric acid (p. 299). Reactions of Gelatin.—Gelatin is precipitated by mercuric chloride, in this respect resembling peptones, but not by potassium ferrocyanide, by which it is distinguished from albuminoids, and it differs from albumin in not being coagulated by heat. Solution of gelatin dissolves considerable quantities of calcium phosphate; hence this is always present in bone-glues. Gelatin and some of its decomposition products are precipitated by metaphosphoric acid.[41] The precipitate contains about 7 per cent. P2O5, but gradually loses it on washing. Various salts diminish the solubility of gelatin in hot water, and especially those of the alum type. Chrome alum and basic chrome salts are especially powerful, rendering it practically insoluble. The addition of about 3 per cent. ammonium or potassium dichromate causes glue or gelatin to become insoluble by the action of light with the formation of basic salts
- 63. of chromium, and has been utilised in photography and as a waterproof cement. Other colloids besides gelatin are similarly affected. [41] Lorenz, Pflüger’s Archiv, xlvii. pp. 189-195. Gelatin is precipitated by all tannins, even from very dilute solutions; one containing only 0·2 grm. per liter is rendered distinctly turbid by gallotannic acid or infusion of gall-nuts; but some other tannins give a less sensitive reaction. The precipitate is soluble to a considerable extent in excess of gelatin, so that in using the latter as a test for traces of tannin care must be taken to add a very small quantity only. The addition of a little alum renders the reaction more delicate. Whether the precipitate is a definite chemical compound has been disputed, as its composition varies according to whether gelatin or tannin is in excess. Böttinger[42] states that the precipitate produced by adding gelatin to excess of gallotannic acid contains 10·7 per cent. of nitrogen, indicating the presence of 66 per cent. of gelatin on the assumption that gelatin contains 16·5 per cent. N (see p. 57). Digested with water at 130° C., the precipitate is decomposed, yielding a solution which precipitates tannin, and probably indicating the formation of a more acid compound. Gelatin with excess of oak-bark tannin gives a precipitate containing 9·5 per cent. of nitrogen, corresponding to 57·5 per cent. of gelatin. Treated with water at 150° C., this precipitate yielded three products: one soluble in cold water, another in hot only and one insoluble. On addition of a solution of formaldehyde (formalin) to one of gelatin no visible action takes place in the cold, unless the solution of gelatin be very concentrated and alkaline, but on heating, the gelatin is rendered insoluble owing to the formation of a compound with the formaldehyde. From the very small amount of formalin which is required to produce formo-gelatin it is very doubtful if this is a definite compound. [42] Liebig’s Ann. der Ch., ccxliv. pp. 227-32. Weiske[43] states that bone-gelatin, carefully freed from all mineral matter, is not precipitated by tannin till a trace of a salt (e. g. sodium chloride) is added. So far as is known, bone-gelatin is identical with that of skin. [43] Bied. Centr., 1883, p. 673.
- 64. Chondrin is the gelatinous body produced by the digestion of cartilage with water at 120° C. for three hours. In most of its physical properties it is identical with gelatin, but differs from the latter in being precipitated from its solution in water by acetic acid, lead acetate, alum, and the mineral acids when the latter are not present in excess. Chondrin also differs from gelatin in producing a substance capable of easily reducing cupric oxide when it is boiled for some time with dilute mineral acids. It is extremely probable that chondrin is merely an impure gelatine.[44] [44] Cp. Petri, Berichte, xii. p. 267; Mörner, Skand. Archiv f. Physiol., i. pp. 210-243; and Journ. Chem. Soc., 1889, A. p. 736 and Zeit. Physiol. Chem., 1895, xx. pp. 357-364; and Journ. Chem. Soc., 1895, A. i. p. 254. See also Richter, Org. Chem., i. p. 559. Coriin.—Rollet[45] has shown that when hide and other forms of connective tissue are soaked in lime- or baryta-water, the fibres become split up into finer fibrils, and as the action proceeds, these again separate into still finer ones, till the ultimate fibrils are so fine as to be only distinguished under a powerful microscope. At the same time, the alkaline solution dissolves the substance which cemented the fibres together, and this may be recovered by neutralising the solution with acetic acid, when the substance is thrown down as a flocculent precipitate. This was considered by Rollet to be an albuminoid substance; but Reimer[46] has shown that it is much more closely allied to the gelatinous fibres, and, indeed, is probably produced from them by the action of the alkaline solution. Reimer used limed calf-skin for his experiments, and subjected it to prolonged cleansing with distilled water, so that all soluble parts must have been pretty thoroughly removed beforehand. He then digested it in closed glasses with lime- water for 7-8 days, and precipitated the clear solution with dilute acetic acid. He found that the same portion of hide might be used again and again, without becoming exhausted, which strongly supports the supposition that the substance is merely a product of a partial decomposition of the hide-fibre, and indeed that there is no distinct “cementing substance,” but merely a difference in the hydration or physical condition of the fibre substance which causes it to split more readily in certain directions. The dissolved substance, which he called “coriin,” was purified by repeated solution in lime-water and
- 65. reprecipitation by acetic acid. It was readily soluble in alkaline solutions but not in dilute acids, though in some cases it became so swollen and finely divided as to appear almost as if dissolved. It was, however, very soluble in common salt solution of about 10 per cent., from which it was precipitated both by the addition of much water and by saturating the solution with salt. Reimer found that a 10 per cent. salt solution was equally effective with lime-water in extracting coriin from the hide, and that it was partially precipitated on the addition of acid, and completely so on saturating the acidified solution with salt. Other salts of the alkalies and alkaline earths acted in a similar manner, so that Reimer was at first deceived when experimenting with baryta-water, because, being more concentrated than lime-water, the coriin remained dissolved in the barium salt formed on neutralising with acid, and it was necessary to dilute before a precipitate could be obtained. The slightly acid solution of coriin gave no precipitate either in the cold or on boiling with potassium ferrocyanide, being thus distinguished from albuminoids. The neutral or alkaline solution showed no precipitate with iron or mercuric chloride, copper sulphate, or with neutral lead acetate; but with basic lead acetate, basic iron sulphate, or an excess of tannin a precipitate was produced. Reimer’s analysis showed: Carbon, 45·91; hydrogen, 6·57; nitrogen, 17·82; oxygen, 29·60; and he gives a formula showing its relation to the original fibre, which does not seem supported by sufficient evidence. In all probability coriin is merely an impure degradation-product of hide-fibre or gelatin. [45] Sitz. Wiener Akad., xxxix. p. 305. [46] Ding. Polyt. Journ., ccv. p. 153. Hide Albumin.—The fresh hide contains a portion of actual albumin, viz. that of the blood-serum and of the lymph, which is not only contained in the abundant blood-vessels, but saturates the fibrous connective tissue, of which it forms the nourishment. This albumin is mostly removed from the skin by the liming and working on the beam, which is preparatory to tanning. Probably for sole-leather, the albumin itself would be rather advantageous if left in the hide, as it combines with tannin, and would assist in giving firmness and weight to the leather. It is, however, for reasons which will be seen hereafter, absolutely necessary to get rid of any lime which may be in
- 66. combination with it. The blood must also be thoroughly cleansed from the hide before tanning, as its colouring matter contains iron, which, by combination with the tannin, produces a bad colour. The albumins form a class of closely allied bodies of which white of egg may be taken as a type. They are also related to the casein of milk, to fibrin, and more distantly to gelatin. A good deal of information on the class may be found in Watt’s Dict. of Chem., 2nd ed., article ‘Proteids,’ and Beilstein’s article ‘Albuminaten,’ and in Allen’s ‘Commercial Organic Analysis,’ vol. iv. The most characteristic property of albumins is that of coagulation by heat. The temperature at which this takes place differs somewhat in different members of the group, egg and serum albumin coagulating at 72-73° C. Dry albumins become insoluble if heated to 110° C. for some time. Traces of acid tend slightly to lower, and traces of alkali to raise the temperature of coagulation. Sodium chloride and some other neutral salts favour coagulation. Solutions of albumin become opalescent at a temperature slightly below that at which flakes form. Albumins are also coagulated by alcohol and by strong mineral acids. Coagulated albumin is only soluble in strong acids and alkalies by aid of heat, and strongly resembles keratin (pp. 56, 68). Solutions of albumin are lævorotatory to polarised light. “Acid” and “Alkali” Albumins are formed by the action, in the cold, of dilute acids (such as acetic, hydrochloric) and alkalies on albumin solution. They are uncoagulable by heat, and are precipitated by careful neutralisation, but are soluble in excess of either acid or alkali, or alkaline carbonates. They are thrown out of solution by saturation with sodium chloride or magnesium sulphate. It is doubtful whether albumins combine with either acids or bases, and it is probable that the “acid” or “alkali” albumins are identical with the parapeptones formed in the first stage of peptic digestion. On putrefaction, or on more severe treatment with acids and alkalies, albumins break down in a way similar to gelatin, and yield almost identical products (see p. 57); amido-acids of the acetic series, and tyrosin (para-oxy-α-amido-phenyl-propionic acid) and aspartic (amido- succinic) acid, being the most important. Treatment with alcoholic soda (see p. 62) yields peptones similar to those of gelatin.[47]
- 67. [47] Paal, Ch. Zeit., 1895, p. 1487. Heated for some days with dilute nitric acid (1 : 2) all proteids, including albumins, gelatin and keratins, yield yellow flocks of “xantho- proteic acid,” a substance of somewhat indefinite composition, soluble in ammonia and in fixed caustic alkalies with production of an orange- red or brownish-red colour. Millon’s reagent gives an intense red coloration when heated with albumins, keratins, or gelatin. The reagent is made by dissolving 2·5 grm. of mercury in 20 c.c. of concentrated nitric acid, adding 50 c.c. of water, allowing to settle and then decanting the clear liquid. Albumins, previously purified by boiling with alcohol and washing with ether, when dissolved in concentrated hydrochloric acid (sp. gr. 1·196) by aid of heat, give a violet-blue coloration, but the reaction is often somewhat indefinite. Gelatin, chondrin and keratins do not give this reaction. Treated with a trace of cupric sulphate and excess of caustic potash solution, albumins give a violet, and gelatin and peptones a pink solution (biuret reaction). Dissolved in glacial acetic acid and treated with concentrated sulphuric acid, albumins and peptones give a violet and feebly fluorescent solution. A somewhat similar reaction is obtained if sugar solution be substituted for acetic acid. A solution of albumin rendered strongly acid with acetic acid is precipitated by potassium ferrocyanide, salt, sodium sulphate, lead acetate, mercuric chloride, tannin and picric and tungstic acids. Egg-Albumin is contained in the whites of eggs in membranes which are broken up by beating with water and can then be removed by filtration. When fresh its reaction is slightly alkaline, and it is lævorotatory. According to Lehmann, white of egg contains 87 per cent. of water, and 13 per cent. of solid matter, the latter being almost entirely composed of egg-albumin. This latter coagulates and becomes insoluble in water on heating to 60° C. Vitellin (the albumin or globulin[48] of the yolk) is insoluble in water, and is obtained as a white granular residue on extracting undried egg- yolk with large quantities of ether. It closely resembles myosin, the chief globulin of muscle, but differs from other globulins in being
- 68. soluble in a saturated solution of common salt. A neutral solution of vitellin in very dilute brine coagulates at 70-75° C. [48] Globulin is an albumin soluble in dilute salt solutions, but insoluble in water. Yolks of eggs, preserved by the addition of salt, borax, or formalin, are used for dressing skins in the process of “tawing” (see p. 191). For the analysis of such yolks, see L.I.L.B., p. 159. Their most important constituent for the leather-dresser is egg-oil of which they contain about 30 per cent. Casein, the principal proteid of milk, may be mentioned here in connection with the albumins to which it is closely related, since, though in no way connected with the animal skin, since it is used to some extent as a “seasoning” or glaze for leather, for which it is well adapted, and it is now to a considerable extent a waste product of butter manufacture. It differs from albumins in being very incompletely if at all coagulated by boiling, but separates at once in curdy flakes on the addition of acids (hydrochloric, acetic, butyric), and by the action of rennet. The curd is easily soluble in small quantities of dilute alkalies, lime-water, and salts of alkaline reaction, such as sodium carbonate and borax. If no more than the necessary quantity of alkali is employed for solution, the compound has an acid reaction to phenolphthalein, and like the original milk, is curdled by rennet and dilute acids. Casein may also be dissolved by digestion with diluted mineral or organic acids. Hair, Epidermis and Glands.—These are all derived from the epithelial layer, and hence, as might be inferred, have much in common in their chemical constitution. They are all classed by chemists under one name, “keratin,” or horny tissue, and their ultimate analysis shows that in elementary composition they closely resemble the albumins. It is evident, however, that the horny tissues are a class rather than a single compound. The keratins are gradually loosened by prolonged soaking in water, and, by continued boiling in a Papin’s digester at 160° C., evolve sulphuretted hydrogen, at the same time dissolving to a turbid solution which does not gelatinise on cooling. Keratin is dissolved by caustic alkalies; the epidermis and the softer horny tissues are easily attacked, while hair and horn require strong solutions and the aid of heat to effect complete solution. The caustic alkaline earths act in the same
- 69. manner as dilute alkaline solutions; hence lime easily attacks the epidermis, and loosens the hair, but does not readily destroy the latter. Alkaline sulphides, on the other hand, seem to attack the harder tissues with at least the same facility as the soft ones, the hair being often completely disintegrated, while the epidermis is still almost intact; hence their applicability to unhairing by destruction of the hair. Keratins give the xanthoproteic reaction with nitric acid, and a red coloration with Millon’s reagent, and also resemble albumin, in the fact that they are precipitated from their solution in sulphuric acid by potassium ferrocyanide. By fusion with potash, or prolonged boiling with dilute sulphuric acid, keratin is decomposed, yielding leucin, tyrosin, ammonia, etc. The precipitate produced by the addition of acids to alkaline solution of keratin (hair, horns, etc.), mixed with oil and barium sulphate, has been employed by Dr. Putz as a filling material for leather, for which purpose it acts in the same way as the egg-yolks and flour used in kid-leather manufacture. Eitner attempted to use it for the same purpose with bark-tanned leather, but without much success. Putz has also proposed to precipitate the material after first working its solution into the pores of the leather. Elastic Fibres.—The elastic or yellow fibres of the hide are of a very stable character. They are not completely dissolved even by prolonged boiling, and acetic acid and hot solutions of caustic alkalies scarcely attack them. They do not appear to combine with tannin, and are very little changed in the tanning process. They are present in hide and skin to the extent of less than one per cent. Analytical Methods.—The reactions distinguishing the principal skin constituents are summarised in the following table:— Reagent. Gelatin. Albumins. Keratins. Cold water Swells only Soluble Insoluble. Heated in water Soluble Coagulate at 72° to 75° C. Soluble only at temp. over 100° C. Acetic acid and potassium ferrocyanide to aqueous solution No precipitate Precipitate Precipitate Millon’s reagent No reaction Red coloration Red coloration. Hot concentrated hydrochloric acid No coloration Violet blue No coloration.
- 70. There is no simple method for the quantitative separation of the different constituents of skin. It is, therefore, customary to simply determine the amount of nitrogen which any particular portion of the material may contain, and, as gelatinous fibre, which constitutes by far the greater portion of the true skin, contains 17·8 per cent. of nitrogen, to base the estimation of the amount of skin present upon this figure (see p. 57). The most convenient process for the determination of the nitrogen is that devised by Kjeldahl, which is most easily carried out as follows:— A known weight of the substance which contains about 0·1 gram of nitrogen (0·5 gram of skin, or a corresponding quantity of liquor) is placed in a flask of Jena glass, capable of holding 500-700 c.c. together with 15 c.c. of concentrated sulphuric acid. The contents of the flask are then boiled over a small Bunsen flame for 15 minutes, or more, until all the water has been driven off and the material is quite disintegrated; and are then allowed to cool below 100°. 10 grams of dry powdered potassium persulphate is now added, and the boiling continued till the liquid has become colourless. The operation of boiling should be conducted in a good draught, or in the open air. Before the substance has begun to char it is advisable to place a small funnel in the neck of the flask to prevent, as far as possible, spirting and loss of sulphuric acid.
- 71. Fig. 18.—Kjeldahl Apparatus. The colourless liquid is allowed to cool thoroughly, and the flask is then fitted with a tapped funnel and tube, as shown in Fig. 18. This tube must not be less than 4 mm. in diameter, and with the end in the flask cut diagonally to facilitate drops of liquid falling back again into the flask. It rises obliquely for a height of 12 to 15 inches, is then bent over as shown in the figure and connected by a rubber tube[49] to a 100 c.c. pipette, or similarly shaped tube, the other end of which dips just below the surface of a volume of exactly 50 c.c. of “normal” hydrochloric acid contained in a second flask. About 50 c.c. of distilled water is introduced into the flask containing the treated sample, and after this 100 c.c. of a solution of 50 grams of caustic soda in 100 c.c. of water is carefully and slowly run into the flask by means of the tapped funnel with which it is provided. The contents of the flask are
- 72. now boiled for about half an hour,[50] the normal acid in the receiving flask being kept cool by immersing the latter in cold water. The liquid in this second flask is then titrated with normal sodium carbonate, using methyl orange as indicator. The difference in c.c. between 50 c.c., the volume of acid used, and the quantity of normal sodium carbonate required to neutralise it, when multiplied by 0·014 represents the amount of nitrogen (in grams) in the weight of the substance used for the determination; or if multiplied by 0·0786 shows the weight of hide- fibre in the same quantity of material. Some chemists add copper sulphate, or a drop of mercury before boiling up the substance with the strong sulphuric acid, but the use of such substances introduces complications in the process without, in the case of gelatinous matter, securing more accurate results. It is absolutely necessary that the acids and alkali used should be free from ammonia, and a blank experiment should be made using pure sugar which contains no nitrogen, and a correction applied if necessary for the ammonia they contain.[51] [49] The ends of the glass tubes should fit closely together, so as to expose the rubber as little as possible to the action of ammoniacal vapour. [50] “Bumping” is often very troublesome at this stage, and may be prevented by passing a current of steam from another flask, or ammonia-free air through a tube with a capillary opening into the boiling liquid; fragments of pure zinc, of platinum, or broken tobacco-pipe are much less efficient. It is an additional safeguard against the escape of ammonia to fix a small absorption-tube containing fragments of glass to the absorption-flask. The normal acid is run through this tube into the flask, so as to wet the broken glass, and is finally rinsed into the absorption flask before titrating its contents. [51] Cp. Procter and Turnbull, Jour. Soc. Chem. Ind., 1900, p. 130; also Nihoul, Composition des Cuirs Belges, p. 14 (Bourse aux Cuirs de Liège, Sept. 1901), who advocates the use of potassium permanganate in the oxidation; and Law (Jour. Soc. Ch. Ind., 1902, p. 847). In place of using 10 grm. of potassium persulphate as described, 10 grm. of ordinary potassium sulphate may be used, and potassium persulphate added in small quantities towards the end of the operation till a perfectly colourless solution is obtained.
- 73. CHAPTER IX. THE PHYSICAL CHEMISTRY OF THE HIDE-FIBRE. The nature of the changes which take place in the conversion of raw hide into leather, and the causes of swelling and “falling” in the various stages of the wet-work and tannage are among the most difficult problems with which we have to deal, and no intelligible explanation can be given without taking into account facts which are among the most recent discoveries of physical chemistry; and of which even yet our knowledge is by no means complete. We know from our study of the structure of hide, that it consists in its natural state of gelatinous fibres which are soft and swollen with water, and easy putrescible. When these are dried, they contract and adhere to each other, forming a hard and almost homogeneous mass, resembling in degree, a sheet of glue or gelatine. After the tanning process, the fibres are changed in character, though not in form; they no longer absorb water so freely, and in drying they do not adhere together, but remain detached and capable of independent movement. The leather is therefore porous, flexible, and opaque on account of the scattering of light from the surfaces of the fibres, although the individual fibres are translucent. At the same time, chemical changes have taken place which render the fibres incapable of ordinary putrefaction. Our first necessity, therefore, in the conversion of skin into leather is to dry the fibres without allowing them to adhere. This is accomplished in the most primitive mode of leather dressing, by mechanically working fatty substances into the skin as it slowly dries, so as to coat and isolate the fibres, which are loosened by kneading and stretching; while at the same time the fat forms a waterproof coating which prevents them from again absorbing the water which is necessary to putrefaction. Similar results may be produced by causing chemical changes in the fibres themselves, which render them insoluble in water, and consequently non-adhesive; and a sort of leather may
- 74. even be made by merely replacing the water between the fibres with strong alcohol, in which they are insoluble, and which absorbs and withdraws the water from them, allowing them to shrink and harden, while preventing their adhesion. The merit of having first clearly seen and expressed these cardinal principles in leather production belongs to the now venerable Professor Knapp, who published in 1858 a short paper (Natur und Wesen der Gerberei und des Leders) which is a model of clear explanation and practical experiment. Knapp, however, deals mainly with the changes in the condition of the fibre which are necessary to convert it into leather, and not with their physical causes; and before we can explain the means by which these changes are brought about, we must be acquainted with certain facts and theories about solutions which have become much clearer since he wrote. The particles (molecules) of all substances are drawn together by attractive forces somewhat of the same character as the attraction of gravitation which holds together the solar system, and which is the cause of weight. It is indeed even possible that these forces are identical. Like gravitation, these molecular attractions increase rapidly in intensity as the distance of the attracting bodies diminishes, so that in solids and liquids, where the molecules are near together, they are immensely powerful, while in gases and vapours they are barely perceptible. These attractions are opposed by the motion of heat, which takes the same part in molecular physics which the energy of planetary motion does in the solar system. In solids, the attractive forces hold the molecules rigidly in position, the motion of heat being limited to short vibrations round a fixed point, the effects of which are visible in the expansion caused by rising temperature. If the temperature is increased, most substances become liquid, a condition in which the particles can roll round each other, but are still held together by their mutual attractions, as the sun holds the earth from flying off into space. If the temperature goes on rising, the orbits of the molecules become greater, the liquid expands, and finally molecules fly off at a tangent out of reach of the attractions of the mass of liquid, and are only diverted from their course by colliding with solids or with other flying molecules, from which they rebound. This constitutes the state of vapour or gas.
- 75. The molecules usually consist of groups of atoms. Thus in the vapour of water, each molecule contains one atom of oxygen combined with two of hydrogen, and it is only at immense temperatures that this inner grouping is broken up. Naturally, the more complicated and heavier the molecular group, the more easily it is broken up by outside causes into simpler groupings, and molecules may exist in liquids or solids, which break up before they reach the gaseous form. Of such substances the chemist says that they “cannot be volatilised without decomposition.” In very rare instances does the gaseous molecule consist of a single atom; even those of the most perfect gases, such as hydrogen, oxygen and nitrogen consist of pairs which are not broken up at any known temperature. The pressure of a gas, and its tendency to expand is due simply to the motion and impact of its flying molecules, and it may be noted that at the same temperature and pressure equal volumes of all gases have the same number of molecules, the lighter molecules making up for their want of weight by their greater velocity. The average velocity of a molecule of oxygen (O2) at freezing point is 461 meters per second or about that of a rifle-bullet. It must not be taken however, that in any given solid, liquid, or gas, all the molecules at any temperature move at a uniform velocity, but that each individual molecule may vary from moment to moment from rest up to a very high speed, while the temperature of the mass only represents the average. Thus it happens that in all liquids, and even in solids, a certain proportion of the molecules at any temperature will have a speed sufficient to enable them to leave the surface, and take the form of vapour, while a certain proportion will fall back and be caught and retained. Thus every liquid, and theoretically every solid, has a “vapour- pressure,” rising with the temperature, and depending on it only, and at the boiling temperature of the liquid equal to that of the atmosphere, or about 15 lb. per square inch, and therefore able to form bubbles in the interior of the liquid. If a little of a liquid is confined in a flask, the flask will become filled with its vapour, and so long as any of the liquid is present, the pressure of the vapour will depend only on the temperature and not at all on the respective quantities of liquid or vapour. Neither will it be affected by the pressure of other vapours or gases present in the flask, the total pressure in which will be the sum of the “partial” pressures of all the gases and vapours present.[52]
- 76. [52] Cp. p. 421. The behaviour of gases and vapours has been described in some detail because it possesses very close analogy to that of substances in solution. The molecules of liquids are held together by attractions which are very powerful over the short distances which separate them, amounting in most cases to many tons per square centimeter of sectional area, but the range over which they act is very small. In the interior of the liquid the attractions on one side of a molecule are of course exactly balanced by those on the opposite side, so that it is free to move within the liquid without hindrance, but at the surface a very small part of the force due to the attractions of the surface-layer is unbalanced and acts as a sort of elastic skin holding the liquid together, and is called “surface-tension.” Familiar examples of this are found in the force which supports a drop on the end of a tube, the possibility of laying a slightly oily needle on the surface of water without sinking, and the ability of some flies to walk on water as if it were covered with a sheet of india-rubber. Many liquids will mix or dissolve in each other in any proportions, e.g. water and alcohol; the attraction of the alcohol for the water-molecule being as great or greater than that of alcohol for alcohol, or water for water. In other cases, such as water and oil, or water and petroleum spirit, practically no mixture takes place, their mutual attraction being small; and each retains a considerable surface- tension at the points of contact, though less than that of the free surfaces, since each exerts an attraction on the other. There are also many intermediate cases, such as water with chloroform, carbolic acid, or ether, in which each solvent dissolves a portion of the other, but the two solutions do not mix, but form separate layers. In these cases an equilibrium is attained, in which there is just as much tendency for either of the liquids to pass into as out of the other layer. In this there is an extraordinary resemblance to what has been said of vapour- pressures; and the tendency to pass into solution is often called solution-pressure; and it may be noted that when equilibrium has been reached, not only is the solution-pressure, but the vapour-pressure of each constituent equal in both solutions. Like vapour-pressures, the solution-pressures usually increase with rise of temperature, more of each constituent passing into the other, till at last the composition of the two layers becomes identical, their surface-tensions disappear, and
- 77. complete mixture takes place. With phenol (carbolic acid) and water this takes place at about 70° C. Most of what has been said of the mutual solution of liquids is also true of the solution of solids, but the latter may be divided into two very distinct classes, colloids and crystalloids (which, however, shade off into each other). The colloid or gluey bodies are mostly miscible in any proportion with liquids in which they dissolve, and there is no such thing as a definite point of saturation. There are however some which form jellies which have great analogy to the partially miscible liquids; there is a mutual solubility, a portion of the solid dissolving to a liquid solution, while the remainder of the liquid dissolves in the solid, increasing its volume, but still retaining the characteristics of the solid state. As the temperature is raised, this mutual solubility generally increases, till at a given point the jelly melts, and complete solution takes place, as in the case of partially miscible liquids. These phenomena are of prime importance in the theory of tanning, but their further consideration must be deferred till a few words have been said about the crystalloids. These are characterised by regular crystalline form, indicating that the attractive forces of their molecules are exerted in definite directions, giving them a tendency to attach themselves together in definite geometrical arrangements. They dissolve in themselves no part of the solvent, but are dissolved by it till an equilibrium is reached in which the tendency of further particles of the solid to pass into the solvent is balanced by that of those already dissolved to attach themselves to the remaining solid, or “crystallise out.” Such a solution is “saturated” with respect to the solid residue, but the word has no meaning unless solid crystals are present, and where a body has, as sometimes happens, more than one crystalline form, a solution may be saturated with regard to one of them, and more or less than saturated with regard to another. In “supersaturated” solutions, crystallisation is at once started by the addition of a “seed” crystal of the proper form. If a crystalloid substance, such, for instance, as copper sulphate, be placed in a solvent (e. g. water), the dissolved salt will gradually spread itself through the whole body of the solvent, though in the complete absence of currents in the liquid, the motion is extremely slow, and years may be taken for the diffusion to rise through a few feet. In
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