Cognetics and the Locus of Attention

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Cognetics and the Locus of Attention

• The Humane Interface, Jef Raskin
• Presented by Dana L.Cobb

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Human Performance Factors

• Are independent of a users age, gender, cultural
  background, or level of expertise
• Are are directly applicable to the foundations of
  any interface design
• Include such factors as ergonomics, cognetics,
  conscious/unconscious thought, locus of
  attention, habits, automatic tasks, absorption
  and the resumption of interrupted work

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• Design a human-machine interface in accord with
  the abilities and foibles of humankind, and you
  will help the user not only get the job done but
  also be a happier, more productive person.
• Page 9-10

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Ergonomics

• Ergonomics - The applied science of equipment
  design, as for the workplace, intended to
  maximize productivity by reducing operator
  fatigue and discomfort
• How does this apply to interface design?
• We must master an ergonomics of the mind if we
  want to design interfaces that are likely to work
  well.

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Cognetics

• Cognetics - The study of the applicable,
  engineering scope of our mental abilities
• How does this affect interface design?
• Much of the difficulty users encounter with
  computers and related devices is due to poor
  interface design

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Conscious and Unconscious

• Conscious - Having an awareness of ones
  environment and ones own existence, sensations
  and thoughts
• Unconscious - Mental processes of which you are
  not aware at the time they occur information
  that is not being accessed but that can be
  recovered on demand

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Conscious and Unconscious

• How does this apply to interface design?
• Acknowledging these two distinct sets of limited
  mental abilities and understanding how they work
  in relation to human-machine interfaces is
  essential to designing interfaces
• Designers must also recognize that a stimulus is
  used to trigger the migration of an item of
  information from the unconscious to the conscious

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Properties of the Cognitive Conscious and the
Cognitive Unconscious
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Focus versus Locus

• Focus - To direct toward a particular point or
  purpose (e.g. the object on a computer screen
  that is currently selected)
• Locus - A place, or site

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Locus of Attention

• Locus of Attention - A feature or an object in
  the physical world or an idea about which you are
  intently and actively thinking (e.g. the one
  object, feature, memory, thought or concept upon
  which you are concentrating)
• Howevereach person sees and hears much more than
  just the locus of his or her attention

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Locus of Attention

• How does this apply to interface design?
• Designers must be cognizant of the users locus
  of attention as well as their direct perceptions
• Direct perceptions decay rapidly and do not
  automatically become memories
• Designers would be advised to only use messages
  when the user can make immediate use of the
  message, or when the message will remain
  displayed until it is no longer needed

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Habits

• Habit - A recurrent, often unconscious pattern of
  behavior that is acquired through frequent
  repetition
• Habits can become so strong as to reach a point
  of total loss of conscious control
• Habits CANNOT be undone by any single act of
  willpower

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Habits

• How does this apply to interface design?
• Persistent use of any interface will cause the
  user to develop habits
• Interfaces must be designed in such a way that
  they do not allow the users development of
  habits to cause problems
• Designers must be cognizant of the helpful and
  injurious properties of habit formation

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Habits

• To Do
• Deliberately take advantage of the human trait of
  habit development
• Allow users to develop habits that smooth the
  flow of the work
• To Avoid
• Many options to accomplish the same task
• Two or more heavily used applications that differ
  in only a handful of often-used details

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Simultaneous Tasks

• Tasks performed simultaneously may include
• One primary task that is NOT automatic which
  requires your locus of control
• One or more tasks that are automatic
• If two tasks are being performed, neither of
  which is automatic, performance on both tasks
  will degrade (referred to as interference)

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Simultaneous Tasks

• How does this apply to interface design?
• Designers must recognize and account for the
  inevitability of habit formation
• Safety measures may be rendered useless by
  habituation
• Key idea any confirmation step that elicits a
  fixed response soon becomes useless

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Absorption

• Users have only one locus of attention a user
  cannot attend to multiple simultaneous stimuli
• When a users locus of attention shifts, it is
  because he has lost the old and acquired the new
  (there cannot be two)
• An intense focus will require a greater stimulus
  to affect a change

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Absorption

• How does this apply to interface design?
• The goal of interface design is to leave the task
  as the locus of the users attention
• Systems should be designed to allow users to
  concentrate on their jobs
• Interfaces should be designed to work, regardless
  of the users state of absorption
• Make sure that users cannot make interface
  operation errors

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Exploitation of Absorption

• When a users attention is fixed, changes can be
  made elsewhere in the system without distracting
  the user
• Interfaces can be carefully designed to mask
  tasks occurring in the background
• Example, Canon Cat

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Interrupted Work

• The resumption of interrupted work may
• Be uninhibited if the interruption lasts only a
  few seconds (within the decay time of short-term
  memory), or
• Need a trigger to prompt the resumption if the
  delay was significant

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Interrupted Work

• How does this apply to interface design?
• Designs are optimal when they return a user to
  the point where he or she left off
• Return user to the last web page viewed, rather
  than the home page
• Return user to the place in a document where he
  or she was last working when it was closed or
  saved, rather than the uppermost left corner
• Computers already have the necessary hardware to
  accomplish this

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Questions/Discussion

• What do you think is a more important
  consideration in interface design, conscious or
  unconscious thought?
• Why do applications continue to use delete
  confirmation when acceptance of the confirmation
  has become so routine (and thus risky? What
  would be better?
• Why arent applications like Word designed to
  open at the point where you left off?