Transcript Understanding Users Cognition & Cognitive Frameworks

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
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Attention
Perception and recognition
Memory
Learning
Reading, speaking, listening
Decision-making, problem-solving, reasoning,
planning, making analogies
Attention
• Involves
– 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
– Whether information presented/displayed is
easy to understand and manipulate
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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
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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
– 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
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Use external representations (e.g., notes, diaries, lists, and
other external reminders)
– Computational offloading
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Use of a tool in conjunction with external reminders (e.g.,
use a calculator to solve a mathematical problem)
– Annotating and cognitive tracing
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Modify representations to reflect changes that occurred
(e.g., crossing off or underlining completed tasks on a list)