Understanding Users Cognition & Cognitive Frameworks Dr. Dania Bilal IS 588 Spring 2008

Cognition What goes on in our minds when carrying out activities Involves cognitive processes Attention Perception and recognition Memory Learning Reading, speaking, listening Decision-making, problem-solving, reasoning, planning, making analogies

Attention Involves Ease and difficulty of attention depends on auditory and/or visual senses Ease and difficulty of attention depends on Whether we have goals Based information to look for, time involved Will drive browsing, scanning or Searching, asking friends

Attention See Text, fig. 3.2, p. 96. Whether information presented/displayed is easy to understand and manipulate Dense vs. simple screens Visual cues used and appropriateness Spacing, bordering, fonts Instructions to carry out tasks See Text, fig. 3.2, p. 96.

Attention: Design Implications Make information salient Use graphics, color, animation, ordering of items, spacing, sequencing of information. Avoid cluttering interface Use commonly used metaphors Use fill-ins as appropriate Use meaningful icons See p.101 for additional design for attention

Memory Allows recalling knowledge Humans can’t recall everything they store in their memories Filtering process is used to decide on information to process and memorize Information is encoded into the brain and retrieved based on context in which it is encoded

Cognition Recognition is easier than recall GUIs supports recognition Web browsers support recognition Command-driven and DOS-based systems don’t support recognition Why? George Miller’s theory: 7+or -2

Memory Supporting recall See also text, p. 110 for design implications Design based on familiarity Design based on mnemonics Design based on context or relevance of information to user Example: what’s the name of your first significant other? Used to authenticate a user’s forgotten password. See also text, p. 110 for design implications

Reading, Speaking, Listening Depends on ease with which people can read, speak, and listen Reading can be quicker than speaking or listening Listening requires less cognitive effort than reading or speaking Preference of listening vs. reading depends on person’s cognitive ability Design Implications: Text, p. 114.

Cognitive Frameworks Represent and predict user behavior Have impact on interaction design Mental models Theory of action Information processing External cognition Distributed cognition

Mental Models Knowledge people have of how to interact with a system and how the system works The more people learn about a system and how it functions, the more their mental models develop. Question: Why do people use erroneous or incomplete or inaccurate mental models when interacting with a system?

Mental Models Most people have poor mental models of how the Internet, search engines, and other computer-based technologies work. Norman (83): users mental models are often incomplete, easily confusable, based on inappropriate analogies, and superstition. They find it difficult to identify, describe, or solve a problem, and lack the words or concepts to explain what’s happening.

Mental Models What is needed of users to do about their mental models? How should interaction designers address these problems in designing systems? Students: Discuss these questions in relation to: User’s role System designer’s role

Theory of Action Norman (1986) specifies 7 stages of an activities based on theory of action. Establish a goal Form an intention Specify action or sequence Execute action Perceive the system state Interpret the state Evaluate the system state vis-à-vis goal and intention

Theory of Action Students: Use the stages of this theory and apply it to an activity for interacting with a Web engine. How do the stages apply to your activity? Are they linear or non-linear based on your activity? What’s wrong with this theory?

Theory of Action Core concepts Gulf of execution Gulf of evaluation Best represented in the figure showing how these two gulfs can be bridged (text, p. 121). Roles of designers and users in bridging the gulfs to reduce cognitive effort required to complete a task.

Information Processing Human mind as an information processor Information enters and exit the mind through a series of ordered processing stages. See Text, fig. 3.11, p. 123. Approach is based on modeling mental activities that happen exclusively in the head. Students: Provide comments about the model.

Alternative approach to Information processing model Study of cognitive activities in the context in which they occur, analyzing cognition as it happens. Focus on environment and how certain structures can aid cognition and reduce cognitive load

Reducing cognitive load Externalizing cognition Externalizing to reduce memory load Use external representations (e.g., notes, diaries, lists, and other external reminders) Computational offloading Use of a tool in conjunction with external reminders (e.g., use a calculator to solve a mathematical problem) Annotating and cognitive tracing Modify representations to reflect changes that occurred (e.g., crossing off or underlining completed tasks on a list)