Chapters 6 & 7: Affective Engineering & Evaluation

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

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. Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

The relationship between HCI design factors, affective qualities and emotions
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. Copyright 2006 John Wiley & Sons, Inc

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 is the users’ belief that using the system will enhance their performance. Perceived ease of use is the users’ belief that using a particular system would be free of effort. Figure 6.6: The Technology Acceptance Model (TAM) adapted from Davis ‘attitude’ was excluded from the model’s application. Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

Table 6.2 Attitudes of Interest
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 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 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) Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

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). 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. Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

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 System satisfies our aesthetic and affective needs and is attractive for its own sake Aesthetically pleasing Engaging Trustworthy 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. Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

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 Copyright 2006 John Wiley & Sons, Inc

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 Copyright 2006 John Wiley & Sons, Inc

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 Experiments Controlled Experiments Computer Simulation Human Information Processing Theory Copyright 2006 John Wiley & Sons, Inc

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 Copyright 2006 John Wiley & Sons, Inc

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 Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

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). Copyright 2006 John Wiley & Sons, Inc

Preferences Dialog Box – good?
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, drop- down lists Copyright 2006 John Wiley & Sons, Inc

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, OK navigate right to left looking through tabs and then on dialog box. Lexical Components – tabs and tab drop-down menus, option box, text boxes, command buttons, check boxes, drop- down lists multiple tabs available (more than can show) each tab has drop-down Copyright 2006 John Wiley & Sons, Inc

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. Copyright 2006 John Wiley & Sons, Inc

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 Copyright 2006 John Wiley & Sons, Inc

Chapters 6 & 7: Affective Engineering & Evaluation

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