IE 486 Work Analysis

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IE 486 Work Analysis Design II
Instructor Vincent Duffy, Ph.D. Associate
Professor of IE Lecture 6 Decision Making
Uncertainty Thurs. Feb. 1, 2007
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An introduction to human decision making

• First review end of cognition (lecture 5) and
  relationship to decision making (lecture 6)
• Re-introduce QOTD as part of lecture today
• Then briefly discuss plan for tomorrow in lab

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6. Long term memory

• Design implications
• The user is unlikely to develop the same level of
  detail (recall) in the use of a product compared
  to the designer
• Therefore, when possible, it is a good idea to
• Encourage frequent use of information
• Take advantage of frequency and recency
• then over time, the task may become more
  automatic
• Standardize and use memory aids
• Eg. Give list of instructions for sending fax
• Carefully design information to be remembered
• Make it meaningful and avoid the use of technical
  jargon when possible

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7. Attention and mental resources

• If we devote cognitive resources to one activity,
  others are likely to suffer
• Eg. Study of the use of cell phones and driving
  suggests that accidents are 5x more likely
• The rate is roughly equivalent to driving drunk
• Consider multiple resources
• Eg. One can not read a book and watch tv at the
  same time.
• However, one can listen to the spoken version of
  the book while watching tv.
• Visual and auditory processing requires separate
  resources.

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8. Conclusions

• Some general design implications
• Consider issues related to
• Divided attention,
• controlled vs. automatic processing
• multiple resources
• Make the input mode dissimilar when possible
• eg. Take advantage of different pools of
  resources.
• Automation (or more automatic processing of
  information) allows better time-sharing of mental
  resources.
• Convey Priority - Let the user know the
  importance of each task to better allocate
  (mental) resources.

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Overview of human decision making

• 1. Overview of human decision making
• 2. An example anesthesiology team in hospital
• 3. What is the problem with heuristics for
  decision making?
• 4. Naturalistic decision making
• 5. Skill rule and knowledge based task
  performance
• 6. Improving human decision making

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IE 486 - Lecture 6 - QOTD

• QOTD 1. What are heuristics?
• QOTD 2. How can we model task performance
  considering the cognitive aspects of tasks?
• QOTD 3. What are some ways to improve human
  decision making through human factors engineering
  design?

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1. Overview of human decision making

• According to Wickens (ch.7)
• Decisions are made either
• intuitively - quick and relatively automatic or
• analytically - slow, deliberate and controlled

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1. Overview of human decision making

• QOTD 1. What are heuristics?
• Simplifications in decision making
• do not always guarantee best solution due to
  biases or misperceptions
• eg. satisficing (Simon, a psychologist 1957)
• suggests a decision maker generates alternatives
  until an acceptable (not necessarily optimal)
  solution is found
• it is believed that many people will judge that
  going beyond this to identify something better
  has too little advantage to make it worth the
  effort.
• Why?
• People have limited cognitive capacity and
  limited time

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1. Overview of human decision making

• How do economists believe we make decisions?
• Rational decision making - it is expected that
  the decision maker will find the optimal
  solution
• based on our concept of what is useful (utility)
  and willingness to accept risk

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2. An example anesthesiology team in hospital

• 5 medical procedures are to be performed urgently
  on 5 different patients in two different
  buildings
• there are only 3 anesthesiologists plus the one
  in charge who is supposed to be available in
  case of incoming unexpected emergency
• classical or normative decision making theory
  suggests there are different alternatives with
  different likelihood of outcome and each has an
  expected utility (good/bad payoff)

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2. anesthesiology team in hospital

• 4 possible alternatives
• the one in charge begins a procedure and no
  emergency occurs
• or the one in charge begins a procedure and an
  emergency occurs
• or she doesnt begin a procedure and an emergency
  comes in
• or she doesnt begin a procedure and an emergency
  doesnt come in
• see p. 160 for expected outcomes based on
  likelihood and utility/payoffs

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3. What is the problem with heuristics for
decision making?

• The decisions are subject to biases
• 1. A limited number of hypotheses is generated
• 2. memory research suggests people will recall
  what was most frequently or most recently
  considered - most readily available.
• 3. Certain cues may lead to a conclusion - then
  not enough is then done to eliminate other
  possibilities
• 4. Overconfidence - people tend to believe they
  are right more often than they really are
• 5. Cognitive fixation - people tend to ignore
  cues that are contrary to their original belief

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4. Naturalistic decision making

• Decisions in the field
• these ideas are considered outside the
  experimental world
• It is suggested by some that this is more useful
  that experimental studies done in labs.
• However, Wickens suggests that these are
  complementary to experimental evidence
• For ill structured problems
• under time constraints and time stress
• high risk and multiple people involved

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5. Skill, rule and knowledge based task
performance

• QOTD 2
• Q. How can we model task performance considering
  the cognitive aspects of tasks?
• Rasmussen suggests 3 levels of cognitive
  control and that people operate at one of the
  levels depending on the nature of the task and
  their experience
• skill based - reacting to perceptual elements in
  an automatic, subconscious level
• rule based - rely on if-then associations between
  cues and actions
• typical of those with familiarity but not
  extensive experience
• knowledge based- when the situation is novel and
  there is no rule or previous experience to draw
  on

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6. Improving human decision making

• QOTD 3
• Q. What are some ways to improve human decision
  making through human factors engineering design.
• Eg. Parachutist has a chute that fails to open
  properly
• after trying to untangle the cords, they deploy
  the reserve chute too late - at 200 ft.
• To reduce chance of an accident
• a redesign could have helped recognition of the
  trouble and awareness of the critical time
  issue
• different colors for cloth and cords could have
  helped diagnosis and
• an altitude sensor (with auditory alarm) could
  have given awareness about time running out

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6. Improving human decision making

• in complex environments can be helped by training
• using computer support
• to teach pattern recognition
• break the process into different cognitive steps
• People overrely on rapid, intuitive decisions
  rather than perform the more difficult analyses
  (Pierce, 1996)
• This suggests that decision aids can support
  decision making if they can help counteract
  this tendency to take shortcuts (or
  satisficing) tendency
• especially when the decision is important, and
  when there is enough time to do the analysis

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Tomorrow in lab

• Review lab 1, part 1
• Turn in reports
• Demonstrate quantitative aspects related to
  decision making uncertainty (tutorial)
• Introduce Lab 2