copyright 2006 john wiley & sons, inc chapters 6 & 7: affective engineering & evaluation...

Copyright 2006 John Wiley & Sons, Inc

Chapters 6 & 7: Affective Engineering & Evaluation

HCI: Developing Effective Organizational Information Systems

Dov Te’eni

Jane Carey

Ping Zhang


Learning Objective

Explain the importance of affect and how it can be engineered.


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.


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.


Learning objective

Describe the main elements and mechanisms of affect.


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.


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’’. 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.


A. Classical

Figure 6.3 Affective impressions in homepages. Adapted from (Kim, Lee and Choi, 2003)

B. Futuristic

The relationship between HCI design factors, affective qualities and emotions

Design factors

Diverse media

Graphic/text

Resolution

Speed, Metaphors

Texture, Shape

Color

Affective qualities

Interactivity

Vividness

Beauty

Structure

Affective impressions

Bright Adorable

Tense Colorful

Mystic Hopeful

Core affect

Elated/Happy

Sad/Gloomy

ProbablyDesign factors

Diverse media

Graphic/text

Resolution

Speed, Metaphors

Texture, Shape

Color

Affective qualities

Interactivity

Vividness

Beauty

Structure


Bright Adorable

Tense Colorful

Mystic Hopeful

Design factors

Diverse media

Graphic/text

Resolution

Speed, Metaphors

Texture, Shape

Color

Affective qualities

Interactivity

Vividness

Beauty

Structure


Bright Adorable

Tense Colorful

Mystic Hopeful

Core affect

Elated/Happy

Sad/Gloomy

Probably

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.


Learning Objective

Explain the Technology Acceptance Model and the perceptions of usefulness, ease of use, and enjoyment.


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

Perceived ease of use

Attitude toward using system

Behavioral intention to use

Actual useExternal variables



Attitude toward using system

Behavioral intention to use

Actual useExternal variables

Figure 6.6: The Technology Acceptance Model (TAM) adapted from Davis 1989 - ‘attitude’ was excluded from the model’s application.


Learning Objectives

Explain attitudes and their place in HCI, including satisfaction and computer anxiety.

Explain the concept of flow.


Attitudes 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, pleasant-unpleasant 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.

Table 6.2 Attitudes of Interest

Computer self-efficacy (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


People’s belief that using the system will enhance their performance


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

Flow represents the user's perception of the medium as playful and engaging.

Characterized by Csikzentmihalyi (1975) 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)


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.


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).


Chapter 7 - Evaluation

HCI: Developing Effective Organizational Information Systems

Dov Te’eniJane CareyPing Zhang


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.


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.


EvaluationMetrics

Dialogue Design

Metaphor Design

Analysis

Design

HC

I Principle

s & G

uidelines

Implementation

FormativeEvaluation

SummativeEvaluationCoding

User Needs TestRequirements Determination

Project Selection Project PlanningProject Selection& Planning

Alternative Selection

Media Design

Presentation Design

FormativeEvaluation

FormativeEvaluation

Interface Specification

Task Analysis

User Analysis

Context Analysis

Evaluation

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

LegibleAudibleSafe to use

Cognitive System fits our cognitive strengths and limitations and functions as the cognitive extension of our brain

Fewer errors and easy recoveryEasy to useEasy to remember how to useEasy to learn

Affective System satisfies our aesthetic and affective needs and is attractive for its own sake

Aesthetically pleasing EngagingTrustworthySatisfyingEnjoyableEntertaining and/or Fun

Usefulness Using the system would provide rewarding consequences

Support individual’s tasksCan do some tasks that would not be possible without the systemExtend 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.


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.


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


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 qualitative & quantitative reliability – same results over and over

Cronbach alpha > .7 0r .8 validity – testing what it is supposed to test

content experts


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 analysis

Contextual inquiry

Judgment studies

Usability inspection methods (e.g. heuristic evaluation)

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 ExperimentsControlled Experiments

Computer SimulationHuman Information Processing Theory


Heuristics

Heuristics: higher level design principles when used in practice to guide designs. Heuristics are also called rules-of-thumb. experts applying heuristics lots of them out there

see handout Usability Heuristics


Cognitive Walkthrough

The following steps are involved in cognitive walkthroughs: 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


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.


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 system).


Task

Change password simple mental model:

Username

New Password (perhaps twice)


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 – readstop 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), optionbox, text boxes, commandbuttons, check boxes, drop-down lists


Preferences Dialog Box – bad?

Tabbed Drop-Down Menu

Additional Tabs Navigators

Task level – need user name and new pw

Semantics of the task – tabs, menus (drop-down), etc.

Syntactic – have to search through tabs (a lot) to find Restrictions(?), then pick Password Restrictions, Change Password, OKnavigate right to left looking through tabs and then on dialog box.

Lexical Components – tabs and tab drop-down menus, optionbox, text boxes, commandbuttons, check boxes, drop-down lists


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.


Norman Ch 3 - 4

What factors allow humans to function even though we have limited memory capacity? knowledge in the world great precision of behavior not required natural constraints of world cultural constraints


Norman Ch 3 - 4

What are some examples of good affordances? bad affordances?


Norman Ch 3 - 4

knowing what to do is a function of what? constraints (logical, cultural, semantic,

physical) – limits the number of possibilities

copyright 2006 john wiley & sons, inc chapters 6 & 7: affective engineering & evaluation...

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