1. Instructor: Vincent Duffy, Ph.D. Associate Professor of IE Lecture 6 – Decision Making & Uncertainty Thurs. Feb. 1, 2007 IE 486 Work Analysis & Design II

2. 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

3. 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

4. 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.

5. 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.

6. 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

7. 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?

8. 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

9. 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

10. 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

11. 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)

12. 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 doesn’t begin a procedure and an emergency comes in –or she doesn’t begin a procedure and an emergency doesn’t come in –see p. 160 for expected outcomes based on likelihood and utility/payoffs

13. 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

14. 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

15. 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

16. 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

17. 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

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