L2 Thinking

Patrick Sturt (patrick.sturt@ed.ac.uk) [email_address] Psychology of Thinking & Language

Review of categorical perception Introduce to the mental lexicon, and the problem of lexical access. Introduce some factors that affect lexical access. Introduce models of context effects in recognising ambiguous words. Introduce experimental techniques: Lexical decision Cross modal priming Eye-movement recording Aims of the lecture

Eg. consonants can be classified as : voiced (eg. b/d/g VOT 0 ms ) voiceless (eg. p/t/k VOT 60 ms ) Review: categorical perception perceiving things that lie along a continuum as belonging to one distinct category or another. VOT 5 ms VOT 15 ms VOT 35 ms VOT 25 ms VOT 45 ms VOT 55 ms d o VOT 0 ms t o VOT 60 ms ‘ perceptual boundary’ of 30ms all sound voiced all sound voiceless

categorical perception methodology reminder subjects hear pairs of consonants . Eg. say whether pairs sound the same or different VOT 0 ms VOT 10 ms VOT 25 ms VOT 35 ms VOT 50 ms VOT 60 ms same different same crosses category threshold (30ms)

categorical perception found that small differences between sounds within a category can still be perceived Pisoni & Nash (1974): same same … the category boundary still exists! VOT 0 ms VOT 10 ms VOT 10 ms VOT 10 ms FASTER VOT 5 VOT 15 VOT 35 VOT 25 VOT 45 VOT 55 d o VOT 0 t o VOT 60 all sound voiced all sound voiceless Nonetheless…

approx 75,000 words in memory just 250 msec to find each one Understanding words stored in mental lexicon mental storehouse of words (in LTM) mental lexicon contains lexical entries one per word contains all info about the word spelling/ pronunciation/ meaning etc. ‘ cat’ [kæt] noun

Lexical access lexical access : retrieving a word from the mental lexicon accessing its lexical entry HOUSE seeing/hearing a word starts to activate its lexical entry when the activation is high enough, lexical access takes place threshold : the level of activation needed for lexical access ‘ house’ [haws] noun ‘ toast’ [towst] noun

Random organisation? cloth snooker marathon chair hillside telephone chop monkey horse cheese ballroom cake rain cliff floor slide bomb concert cleaner pullover television piano

We can find out how words are organised by looking at things that make lexical access easy or hard word organisation How do we know whether a word is easy or hard to access? Lexical decision task

Non-words (BRUKE) are ‘fillers’ to check the subject is paying attention we only look at real words lexical decision task HOUSE NOIK SLEEP NURSE BRUKE (400 msec) (450 msec) Press YES or NO for whether the following is a real word in English: FAST response = easy to access SLOW response = hard to access task variant: lexical naming measures time taken to pronounce the word aloud

1. Word Length short words are faster to access than long words E.g. chaos vs. confusion what affects lexical access time? in lexical decision (Chumbley & Balota, 1984) in word naming (Weekes, 1997) strongest for 5-12 letter words also when saying numbers (Klapp, 1974) faster to start saying 91 vs. 77 (syllables: 3 vs. 5)

2. Word Frequency High frequency words = common words ( cat, mother, house ) Low frequency words = uncommon words ( czech, compass ) what affects lexical access time? High frequency are faster to access than Low frequency even when they’re balanced on other features (e.g. length) E.g. Pen vs. Pun Rubenstein et al. (1970)

what affects lexical access time? the prior context lowers the threshold for the word’s activation interacts with frequency low frequency words are facilitated (speeded up) more 3. Priming when word-reading is ‘ facilitated ’ (speeded up) by prior context a) repetition priming (Scarborough et al., 1977) a repeated word is read faster second time round eg. pen … pen pen 1st (‘context’) speeds up pen 2nd pun speeds up pun more than pen speeds up pen

subject sees 2 words must say (YES/NO) whether both are real words doctor grass doctor nurse what affects lexical access time? b) Semantic Priming (Meyer & Schvandeveldt, 1971) suggests … reading doctor somehow speeds up nurse doctor & nurse are linked in our minds (but NOT doctor & grass ) priming : when language processing (eg. reading nurse ) is ‘facilitated’ (speeded up) by prior context (e.g., reading doctor ) SLOW FAST

accounts for priming effects words in memory represented in a ‘network’ each word is a ‘node’ nodes (words) are connected to other nodes related in meaning accessing a word causes activation activation spreads to connected nodes spreading activation model

canary bird animal ostrich mammal Spreading Activation Model yellow doctor dentist fever green baby cradle bed hospital sun rain heat grass nurse delirium

like semantic priming, but for word related in sound (not meaning) trail chute shoot chute what affects lexical access time? … because chute is already ‘warmed up’ by having just activated shoot c) Phonological (sound) Priming (Evett & Taylor, 1982) What does this tell us about how the lexicon is organised? not only a semantic network but also an phonological network SLOW FAST

canary bird animal ostrich mammal Semantic Network yellow doctor dentist fever green baby cradle bed hospital sun rain heat grass nurse delirium

poor pour shorn prawn pawn Phonological Network shin shoot chute shore sharp door dirt shirt short chin ship gin harp sure court

Bruce (1958) participants heard words against background noise better recognition for words in context vs. out of context what affects lexical access time? priming : when language processing is facilitated by prior context 4. context words are recognised better in sentence contexts Lieberman (1963) participants heard words either in isolation or in sentences in isolation, take almost twice as long to recognise

what affects lexical access time? 5. lexical ambiguity Which we will look at in detail in the rest of the lecture… What is the first sentence that comes to mind given the word: BANK COACH BEAM PORT

lexical ambiguity WRITTEN word: ‘lead’ lead [lid] vs. lead [led] homographs : written the same but have different meanings lexical ambiguity : when a word has more than one meaning = polysemous words: bank; straw; letter ambiguity might be only in written or spoken language SPOKEN word: [najt] knight vs. night homophones : sound the same but have different meanings

lexical ambiguity many many words are ambiguous coach, straw, bank, chick, tea/tee, bug, tie, here/hear, mail, you/ewe, bread, letter, plane, eye/I, pound, score, watch, house, table, phone, plate, trip, branch, shore/sure, bed, two/too/to, top, cite/sight, fork, pan, ………….. How do people choose the right meaning?

Effect of context on meaning … but how? is the relevant meaning selected immediately? or do we first consider all meanings? contexts helps select the relevant meaning The fisherman sat down on the bank The businessman put his money in the bank

3 models of context effects Autonomous access model All of a word’s meanings are accessed from the lexicon, regardless of context. Contextually appropriate meaning is selected later in an integration phase. Re-ordered access model All of a word’s meanings are accessed from the lexicon Context can increase the speed with which a meaning becomes available Direct access model: Only contextually appropriate meaning is accessed in the first place.

Understanding ambiguous words Swinney (1979) bugs : insects / listening devices The man wasn’t surprised when he found several spiders, roaches and other bugs in the corner of the room context supports insects but do people still instantly consider both meanings?

Cross-modal lexical decision (Swinney, 1979) target word appears after subjects hear bugs ant (related to “insect”) spy (related to “listening device”) sew (unrelated to either meaning) Participants listen to sentences, and look at a screen words appear on screen lexical decision task … he found several spiders, roaches and other bugs in the corner… AMBIGUOUS CONDITION Slow FAST FAST

Cross-modal lexical decision target word appears after subjects hear insects ant (related to “insect”) spy (related to “listening device”) sew (unrelated to either meaning) Participants listen to sentences, and look at a screen words appear on screen lexical decision task … he found several spiders, roaches and other insects in the corner… UNAMBIGUOUS CONDITION Slow FAST SLOW

Cross-modal lexical decision So both meanings were available immediately after bugs context had no immediate effect AMBIGUOUS CONDITION ant (related to “insect”) spy (related to “listening device”) sew (unrelated to either meaning) But Swinney also tested 3 syllables downstream … several spiders, roaches and other bugs in the corner… baseline FAST SLOW

only relevant meaning remains (3 syllables) downstream Cross-modal lexical decision So both meanings were available immediately after bugs context had no immediate effect UNAMBIGUOUS CONDITION ant (related to “insect”) spy (related to “listening device”) sew (unrelated to either meaning) But Swinney also tested 3 syllables downstream … several spiders, roaches and other insects in the corner… SLOW FAST SLOW

Discussion suggests lexical access makes available all meanings instantly independently of context: but context rapidly “kicks in”: (“integration”) selects the appropriate meaning screens out irrelevant meanings process happens quickly (at least within 3 syllables) Supports Autonomous Access model but is this always true?

in fact, processing can vary, depending on … the particular ambiguous word the particular prior context All Swinney’s words were “balanced” (each meaning occurs roughly equally. What happens with “ biased” words (one meaning occurs more often than another)? Understanding ambiguous words

biased vs. balanced words port harbour wine bark part of tree dog noise BIASED BALANCED more common less common roughly balanced

biased words: common meaning is always accessed uncommon meaning is only sometimes accessed Understanding ambiguous words in fact, processing can vary, depending on … the particular ambiguous word Depends on the particular prior context

Effect of context: Rayner & Duffy (1986); Duffy et al. (1988) eye-tracking ambiguous words balanced (eg. bark) vs. biased (eg. port ) Eye-movements in reading: -difficulty of lexical access can be measured from “ gaze duration” (time spent first fixating a word before moving to another word). To their surprise, the bark was unusual 1 2 3 4 5 6 7 8

Effect of bias: Basic finding (Rayner & Duffy; 1986) eye-tracking ambiguous words balanced (eg. bark) vs. biased (eg. port ) slower gaze duration than control same as control neutral context: He found the bark was… both meanings accessed 2 meanings competing 1 meaning accessed no competition control: howl control: soup Last night the port was…

Effect of context: Duffy et al. (1988) Manipulated whether the disambiguating context came before or after the critical word: CONTEXT BEFORE: CONTEXT AFTER Because they heard it from so far away , the bark/howl was difficult to identify Unfortunately, the bark/howl was difficult to identify, because they heard it from so far away .

Effect of context: Duffy et al. (1988) Also manipulated whether the ambiguous word was balanced (e.g. “bark”) or biased (e.g. “port”): BALANCED: BIASED Because they heard it from so far away , the bark/howl was difficult to identify Even though it had a strange flavour , the port/soup was a great success. The context always disambiguated to the less common meaning (e.g. “wine” meaning of port). Ambiguous words were compared with unambiguous controls

Duffy et al gaze duration results: CONTEXT BEFORE CONTEXT AFTER

Summary of Duffy et al When context after the critical word, lexical access was difficult for the balanced ambiguous word lexical access happens before disambiguating context 2 meanings are accessed at the same time, causing competition, and difficulty When context comes before the critical word, lexical access was difficult for the biased ambiguous word The context promoted the less preferred reading, making it accessed earlier than usual. Caused competition between the two readings. This pattern of results is called the subordinate bias effect

The re-ordered access model most frequent meaning is always accessed ( harbour ) but context can “promote” uncommon meaning ( wine ) If so, both meanings become available together meanings compete, causing difficulty

Subordinate bias effect most frequent meaning is accessed first ( harbour ) this is checked with context but it doesn’t make sense! comprehension break-down have to re-access for 2 nd meaning ( wine ) break-down & re-analysis causes slow-down slow-down when context biases to uncommon meaning both meanings are accessed, but when? (2 accounts) IN SEQUENCE : Integration account ‘ Autonomous/ ordered access’

context strongly biases uncommon meaning When she served it to her guests, the port … Subordinate bias effect slow-down slowdown could be caused by… competition between 2 concurrent meanings (“Re-ordered access”) 1 st (common) meaning being ruled out (“Integration account”)

Dopkins et al (1992) Tried to distinguish between integration account and re-ordered access account, also in an eye-tracking experiment: Positive condition: context highlights a feature of the uncommon meaning, but doesn’t rule out less common: Having been examined by the King, the page was soon marched off to bed. (King highlights “servant” meaning) Negative condition : context rules out common meaning Having been hurt by the bee sting, the page was soon marched off to bed. (Bee-sting rules out “paper” meaning) Neutral condition : Just as Henrietta feared, the page was soon marched off to bed.

Results of Dopkins et al Dopkins et al measured time taken to finish reading the final disambiguating region marched off to bed.

Summary of Dopkins et al Speed up in disambiguating region, both for positive and for negative conditions Shows that the prior context in the positive condition caused selection of the less common meaning, at least some of the time. Does not support integration account: Having been examined by the king, the page… Still no reason to reject “paper” reading of page at this point, so integration model would select “paper” reading. Therefore “integration” model would predict difficulty at “ was soon marched off to bed ”. Results support the “re-ordered access” account. The phrase the king caused the “servant” meaning to be accessed more quickly Therefore less difficulty at “ was soon marched off to bed”.

Summary of Lecture READING: Harley, T. (2001). Psychology of Language . Hove: Psychology Press. Ch 6 Lexical access: The process of retrieving details of a word from long-term store (lexicon). Speed of lexical access is affected by: Length Frenquency Priming How do we process ambiguous words? For balanced words (Swinney 1979), all meanings become simultaneously available, and context is used to select. Context can affect the order with which meanings become available (Duffy et al, 1988; Dopkins et al, 1992).

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