1. Cognetics and the Locus of Attention
The Humane Interface, Jef Raskin
Presented by: Dana L.Cobb

2. Human Performance Factors
Are independent of a user’s 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

3. 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.
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4. 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.”

5. 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

6. Conscious and Unconscious
Conscious - Having an awareness of one’s environment and one’s 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

7. 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

8. Properties of the Cognitive Conscious and the Cognitive Unconscious

9. 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

10. 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)
However…each person sees and hears much more than just the locus of his or her attention

11. Locus of Attention How does this apply to interface design?
Designers must be cognizant of the user’s 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

12. 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

13. 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 user’s development of habits to cause problems
Designers must be cognizant of the helpful and injurious properties of habit formation

14. 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

15. 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)

16. 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

17. Absorption
Users have only one locus of attention; a user cannot attend to multiple simultaneous stimuli
When a user’s 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

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

19. Exploitation of Absorption
When a user’s 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

20. 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

21. 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

22. 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 aren’t applications like Word designed to open at the point where you left off?