2. WHAT IS HCI AND WHY IT IS
IMPORTANT?
How many interactive products are there in everyday use?
(Think for a minute about what you use in a typical day)
Now think for a minute about how usable they are.
How many are actually easy, effortless, and enjoyable to
use?
3. WHAT HCI IS AND WHY IT IS
IMPORTANT?
Human–computer interaction (HCI) is a cross-disciplinary
area (e.g., engineering, psychology, ergonomics, design)
that deals with the theory, design, implementation, and
evaluation of the ways that humans use and interact with
computing devices.
4. WHAT IS INTERACTION DESIGN?
"designing interactive products to support people in their everyday
and working lives”.
Now that it is widely accepted that HCI has moved beyond designing
computer systems for one user sitting in front of one machine to
embrace new paradigms, we, likewise, have covered a wider range of
issues.
These include ubiquitous computing and pervasive computing that
make use of wireless and collaborative technologies.
5. WHAT HCI IS AND WHY IT IS IMPORTANT?
Interaction is a concept to be distinguished from another similar term,
interface.
Interaction refers to an abstract model by which humans interact with
the computing device for a given task, and an interface is a choice of
technical realization (hardware or software) of such a given interaction
model.
Thus, the letter I in HCI refers to both interaction and interface,
encompassing the abstract model and the technological methodology.
7. WHAT HCI IS AND WHY IT IS IMPORTANT?
The early focus of HCI has been in how to design interaction
and implement interfaces for high usability.
The term high usability means that the resulting interfaces
are easy to use, efficient for the task, ensure safety, and lead to
a correct completion of the task.
Usable and efficient interaction with the computing device in
turn translates to higher productivity.
8. PRINCIPLES OF HCI
“Know Thy User”
coined by Hansen in 1971
This principle simply states that the interaction and interface
should cater to the needs and capabilities of the target user of
the system in design.
9. PRINCIPLES OF HCI
“Understand the Task”
Task refers to the job to be accomplished by the user through the use of the interactive system.
10. PRINCIPLES OF HCI
“Reduce Memory Load”
Designing interaction with as little memory load as possible is a
principle that also has a theoretical basis.
Keeping the user’s short-term memory load light is of particular
importance with regard to the interface’s role as a quick and easy
guidance to the completion of the task.
The capacity of the human’s short-term memory (STM) is about 5–9
chunks of information (or items meaningful with respect to the task),
famously known as the “magic number”.
11. PRINCIPLES OF HCI
“Strive for Consistency”
In the longer term, one way to
unburden the memory load is
to keep consistency.This
applies to (a) both within an
application and across different
applications and (b) both the
interaction model and interface
implementation.
12. PRINCIPLES OF HCI
“Remind Users and Refresh Their Memory”
Research shows that our brain internally rehearses information encoding during
multitasking. Even a single task may proceed in different contextual spans.
13. PRINCIPLES OF HCI
“Prevent Errors/Reversal of Action”
The interaction and interface should be designed
to avoid confusion and mental overload.
One effective technique is to
present or solicit only the relevant
information/action as required at a given time.
Inactive menu items are good examples
of such a technique.
14. PRINCIPLES OF HCI
“Naturalness”
Naturalness refers to a trait that is reflective of various operations in our everyday
life.
A better approach is to model interaction “metaphorically” to the real life
counterpart, extracting the conceptual and abstract essence of the task.
One might consider this rotation technique
to be metaphoric because it abstracts the interaction
object into the shape of a sphere, the most rotational
object we know.
15. A natural or metaphoric interface will also have affordance, a
property that
appeals to our innate perception and cognition, thus making it so
intuitive that
the interface would require almost no learning.
#2:Many products that require users to interact with them to carry out their tasks (e.g., buying a ticket online from the web, photocopying an article, pre-recording a TV
program) have not necessarily been designed with the users in mind. Typically, they have been engineered as systems to perform set functions. While they may work effectively from an engineering perspective, it is often at the expense of how the system will be used by real people.
#4:This entails creating user experiences that enhance and extend the way people work, communicate, and interact.
#8:Despite its importance, good HCI design is generally difficult, mainly because it is a multiobjective task that involves simultaneous consideration
of many things, such as the types of users, characteristics of the tasks, capabilities and cost of the devices, lack of objective or exact quantitative
evaluation measures, and changing technologies, to name just a few. A considerable knowledge in many different fields is required.
Ideally, comprehensive information (e.g., age, gender, education level, social status, computing experience, cultural background) about the
representative target user should be collected and analyzed to determine their probable preferences, tendencies, capabilities (physical and mental),
and skill levels.
#9:Another almost-commonsensical principle is to base HCI design on the understanding of the task.
Take the subtask (for a larger application) for “changing the Wi-Fi connection access point” for a smartphone. For an expert user experienced
in computer networks, the task might be modeled with detailed steps, asking the user to select from a pool of available nearby access points
based on their characteristics such as the signal strength, bandwidth, security level, and so forth. On the other hand, for a casual user, the
subtask might only involve entering a password for the automatically selected access point.
#11:For instance, the user is likely to get confused and exhibit erroneous responses if the same subtask is involved, at different
times, for different interaction steps or interface methods.
Note that the exact same subtasks may appear across different applications as well. Aside from being able to remember what to do, consistency and familiarity also lead to higher acceptability and preference.
One way the Microsoft Windows®–based applications maintain their competitiveness is by promoting consistent and familiar interfaces
#12:For instance, in an online shopping application, one might cycle through the entry of different types of information: item selection,
delivery options, address, credit card number, number of items, etc.
To maintain the user’s awareness of the situation and further elicit correct responses, informative, momentary, or continuous feedback will
refresh the user’s memory and help the user complete the task easily.
#13:Also, having the system require the user to choose from possibilities (e.g., menu system) is
generally a safer approach than to rely on recall (e.g., direct text input).
#14:Naturalness:
For instance, a perfect HCI may one day be realized when a natural language–based conversational interface
is possible, because this is the prevalent way that humans communicate. However, it can be tricky to directly translate real-life styles and
modes of interaction to and for interaction with a computer.
Affordances:
In the example of the ARCBall, the spherical shape of the rotator GUI
may be regarded to exhibit a high level of affordance, requiring no
explanation as to how to rotate the object.
