Transcript Chapter 6 Affective Engineering

Chapters 6 & 7:
Affective Engineering &
Evaluation
HCI: Developing Effective Organizational
Information Systems
Dov Te’eni
Jane Carey
Ping Zhang
Copyright 2006 John Wiley & Sons, Inc
Learning Objective
 Explain the importance of affect and how it
can be engineered.
Copyright 2006 John Wiley & Sons, Inc
Affect includes …
 Perceived enjoyment is the extent to which
fun can be derived from using the system as
such.
 Computer anxiety is emotions about the
implications of using a computer such as the
loss of important data or other important
errors.
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Cognition and Affect
 Cognition interprets and makes sense of the
world.
 Affect evaluates and judges, modulating the
operating parameters of cognition and
providing warning of possible dangers.
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Learning objective
 Describe the main elements and mechanisms
of affect.
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What is affect?
 Affect is a general term for a set of psychological
processes and states including emotions, moods,
affective impressions and attitudes.

The new psychological basis of HCI that balances and
integrates affective and cognitive aspects view is
rapidly gaining popularity.
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Affect and Design
 Affective qualities
 beauty, overview, title, shape, structure, texture, menu,
main images, and color (Zhang and Li, 2004).
 bright, tense, strong, static, deluxe, popular, adorable,
colourful simple, classical, futuristic, mystic, and
hopeful (Kim, Lee, and Choi, 2003).
 Lavie and Tractinsky (2004) identified two dimensions
in users’ perceptions: ‘‘classical aesthetics’’ and
‘‘expressive aesthetics’’.
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classical aesthetics dimension pertains to aesthetic
notions that emphasize orderly and clear design.
expressive aesthetics dimension is manifested by the
designers’ creativity and originality and by the ability to
break design conventions.
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A. Classical
B. Futuristic
Figure 6.3 Affective impressions in homepages.
Adapted from (Kim, Lee and Choi, 2003)
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The relationship between HCI design
factors, affective qualities and emotions
Design factors
Affective qualities
Affective impressions
Diverse media
Interactivity
Bright
Adorable
Graphic/text
Vividness
Tense
Colorful
Resolution
Beauty
Mystic
Hopeful
Speed, Metaphors
Structure
Color
Probably
Texture, Shape
Core affect
Elated/Happy
Sad/Gloomy
Figure 6.4 Design impacts emotions – examples design factors, affective qualities,
impressions and affect in web-based design. These lists are tentative and partial.
Effects of emotions on cognition
Table 6.1: Effects of emotions on cognition (adapted from
Hudlicka, 2003)
Anxiety and attention: Anxiety limits attention, predisposing
attention to source of danger
Affect and memory: Mood biases memory recall (positive
mood induces recall of positive information)
Obsessiveness and performance: Obsessiveness delays decision
making, reduces recall of recent events, reduces confidence in
ability to distinguish between real and imagined events.
Affect and judgment: Negative mood decreases and positive
increases perception of self control, anxiety predisposes
towards interpretation of ambiguous stimuli as threatening.
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Learning Objective
 Explain the Technology Acceptance Model
and the perceptions of usefulness, ease of
use, and enjoyment.
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Technology Acceptance Model

The Technology Acceptance Model (Davis, 1989)
is one of the leading models in IS to explain
attitudes towards using a system.
Perceived
usefulness
Attitude
toward using
system
External
variables
Behavioral
intention to
use
Actual use
Perceived
ease of use
Figure 6.6: The Technology Acceptance Model (TAM) adapted from
Davis 1989 - ‘attitude’ was excluded from the model’s application.
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Learning Objectives
 Explain attitudes and their place in HCI,
including satisfaction and computer anxiety.
 Explain the concept of flow.
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Attitudes

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Attitude represents a summary evaluation of an
object.
An attitude towards an object, such as a computer
system, “represents a summary evaluation of a
psychological object captured in such attribute
dimensions as good-bad, harmful-beneficial, pleasantunpleasant and likable-dislikeable” (Ajzen, 2001, p.
27).
Attitudes are influenced by cognition (beliefs about the
object) as well as affect (emotions towards the object)
and result in a tendency to behave in a certain way
towards the object (i.e., an intention to act).
Attitudes towards computers are influenced by
individual characteristics such as personality and
background.
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Table 6.2 Attitudes of Interest
Computer selfefficacy (CSE)
People’s belief about their capabilities to use computers in diverse
situations (if high, positive evals of system)
Flow
Holistic sensation that people feel when they act with total
involvement
Perceived
usefulness
People’s belief that using the system will enhance their performance
Perceived ease of
use
People’s belief that using a particular system would be free of effort
Computer anxiety
Anxiety about the implications of using a computer such as the loss
of important data or other important mistakes
Perceived
enjoyment
The extent to which fun can be derived from using the system as
such.
Satisfaction
The fulfillment of positive expectations of using a computer
Flow and Playfulness
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Flow represents the user's perception of the
medium as playful and engaging.
Characterized by Csikzentmihalyi (1975)
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theory of engagement with something
noted in intense interactive experiences
characterized by time dilatation, hyperfocusing,
sense of control over environment, shutting out of
stimuli
intrinsic experience
measurable - Trevino and Webster (1992)
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Design and Flow
 HCI design should be untaken with the above
dimensions of flow in mind.
 Interfaces should afford users with a perceived sense
of control.
 The interface must also disappear into the
background in order to give the user the perceived
sense of interaction focus.
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Satisfaction
 Satisfaction is a positive affect resulting from the
evaluation of the use of the computer system.

users have certain expectations, they then confirm (or
disconfirm) these expectations and, as a result, form a
feeling of satisfaction (Bhattacherjee, 2001).
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Chapter 7 - Evaluation
HCI: Developing Effective Organizational
Information Systems
Dov Te’eni
Jane Carey
Ping Zhang
Copyright 2006 John Wiley & Sons, Inc
Learning Objectives
 Explain what evaluation is and why it is
important.
 Understand the different types of HCI
concerns and their rationales.
 Understand the relationships of HCI concerns
with various evaluations.
 Understand usability, usability engineering,
and universal usability.
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Learning Objectives
 Understand different evaluation methods and
techniques.
 Select appropriate evaluation methods for a
particular evaluation need.
 Carry out effective and efficient evaluations.
 Critique reports of studies done by others.
 Understand the reasons for setting up
industry standards.
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Evaluation
Project Selection
& Planning
Analysis
Project Selection
Project Planning
Requirements
Determination
Context
Analysis
User Needs Test
User
Analysis
Task
Analysis
Formative
Evaluation
Alternative Selection
Interface Specification
Design
Metaphor Design
Media Design
Dialogue Design
Presentation Design
Coding
Implementation
Formative
Evaluation
Formative
Evaluation
Summative
Evaluation
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HCI Principles & Guidelines
Evaluation
Metrics
the determination of
the significance,
worth, condition, or
value by careful
appraisal and study.
What to evaluate?
HCI
Concern
Description
Sample Measure Items
Physical
System fits our physical strengths
and limitations and does not cause
harm to our health
Legible
Audible
Safe to use
Cognitive
System fits our cognitive strengths
and limitations and functions as the
cognitive extension of our brain
Fewer errors and easy recovery
Easy to use
Easy to remember how to use
Easy to learn
Affective
Aesthetically pleasing
System satisfies our aesthetic and
affective needs and is attractive for its Engaging
Trustworthy
own sake
Satisfying
Enjoyable
Entertaining and/or Fun
Usefulness
Using the system would provide
rewarding consequences
Support individual’s tasks
Can do some tasks that would not be
possible without the system
Extend one’s capability
Rewarding
When to evaluate
 Formative Evaluation: conducted during the
development of a product in order to form or
influence design decisions.
 Summative Evaluation: conducted after the product
is finished to ensure that it posses certain quality,
meets certain standards or satisfies certain
requirements set by the sponsors or other agencies.
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When to evaluate
 Use and Impact Evaluation: conducted
during the actual use of the product by real
users in real context.
 Longitudinal Evaluation: involving the
repeated observation or examination of a set
of subjects over time with respect to one or
more evaluation variables.
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Issues in Evaluation
 Evaluation Plan
 Stage of design (early, middle, late)
 Novelty of product (well defined versus exploratory)
 Number of expected users
 Criticality of the interface (e.g., life-critical medical
system versus museum-exhibit support)
 Costs of product and finances allocated for test
 Time available
 Experience of the design and evaluation team
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Usability and Usability Engineering
 Usability: the extent to which a product can be used
by specified users to achieve specified goals with
effectiveness, efficiency and satisfaction in a
specified context of use.
 Collect data and analyze throughout design and
development process
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qualitative & quantitative
reliability – same results over and over
 Cronbach alpha > .7 0r .8
validity – testing what it is supposed to test
 content experts
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Usability Engineering Methods
Field strategies
(Settings under conditions as natural as possible)
Respondent strategies
(Settings are muted or made moot)
Field studies
Ethnography and interaction
Contextual inquiry
Judgment studies
Usability inspection methods (e.g. heuristic evaluation)
analysis
Field experiments
Beta testing of products
Studies of technological change
Sample surveys
Questionnaires
Interviews
Experimental strategies
(Settings concocted for research purposes)
Theoretical strategies
(No observation of behavior required)
Experimental stimulations
Usability testing
Usability engineering
Formal theory
Design theory (e.g. Norman’s 7 stages)
Behavioral theory (e.g. color vision)
Laboratory Experiments
Controlled Experiments
Computer Simulation
Human Information Processing Theory
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Heuristics
 Heuristics: higher level design principles
when used in practice to guide designs.
Heuristics are also called rules-of-thumb.
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experts applying heuristics
lots of them out there

see handout Usability Heuristics
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Cognitive Walkthrough
 The following steps are involved in cognitive
walkthroughs:
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designer and expert evaluators walk through the
app, pretending they are typical users
(according to documented characteristics)
walk through identified key tasks
identify problems
make fixes
 may also use Guidelines for this
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Inspection with Conceptual
Frameworks such as the TSSL model
 Another structured analytical evaluation method is to
use conceptual frameworks as bases for evaluation
and inspection. One such framework is the TSSL
model we have introduced earlier in the book.
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TSSL Levels
 The task level pertains to the information requirements
that have to be met (goals).
 The semantic level pertains to the set of objects and
operations through which the computer becomes
meaningful to the user (implementation-independent
words – objects and actions - what can be done).
Relates user world to software world.
 The syntactic level dictates the rules of combining the
semantic objects and operations into correct instructions
(rules of how to use objects and actions correctly –
grammar – how to do something).
 The lexical level describes the way specific computer
devices are used to implement the syntactic level, e.g.,
move a mouse pointer to the document label and click
twice to open it (specific way to do something on specific
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system).
Task
 Change password

simple mental model:
Username
New Password (perhaps twice)
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Preferences Dialog Box – good?
Title Area
Tree menu
Task level – need user name, new pw
Semantics of the task –
menus, navigate tree on left,
menu sections (headings)
Syntactic – preferences
dialog box org’d well – reads
top to bottom, left to right,
consistent fonts, right side
changes with left choice,
orienting title at top – walk through
task
Lexical Components – tree
menu (with labels), option
box, text boxes, command
buttons, check boxes, dropdown lists
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Preferences Dialog Box – bad?
Task level – need user name and
new pw
Semantics of the task –
tabs,
menus (drop-down), etc.
Additional Tabs
Navigators
Syntactic – have to search through
tabs (a lot) to find Restrictions(?),
then pick Password Restrictions,
Change Password, OK
navigate right to left looking
Tabbed Dropthrough
tabs and then on dialog
Down Menu
box.
Lexical Components – tabs and tab
drop-down menus, option
box, text boxes, command
buttons, check boxes, dropdown lists
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Empirical Methods
 Surveys and Questionnaires
 Used to collect information from a large group of
respondents.
 Interviews (including focus groups)
 Used to collect information from a small key set of
respondents.
 Experiments
 Used to determine the best design features from many
options.
 Field studies
 Results are more generalizable since they occur in real
settings.
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Norman Ch 3 - 4
 What factors allow humans to function even
though we have limited memory capacity?
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knowledge in the world
great precision of behavior not required
natural constraints of world
cultural constraints
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Norman Ch 3 - 4
 What are some examples of
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good affordances?
bad affordances?
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Norman Ch 3 - 4
 knowing what to do is a function of what?

constraints (logical, cultural, semantic,
physical) – limits the number of possibilities
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