B U 3 6

Rule: A card with a vowel (p) will have an even number on the other side (q). Which card or cards should be turned over to test the rule?

People do pretty well applying modus ponens but have trouble applying modus tollens. (The problem is easier when real world examples are used.)

~ p p ~ q q

HeuristicsRepresentativenessAvailabilitySimulation

Problem solvingGestalt influenceInsightFunctional fixednessEinstellungAnalogies (see Goldstein)

HeuristicsRepresentativenessAvailabilitySimulation

Heuristicgeneral rule (“rule of thumb”)lacks detailsworks much of the time

but prone to error

Algorithmspecific rule or procedure (formula)often detailed, intricatehighly accurate

(gives correct answer as long as applied correctly)

HeuristicsRepresentativeness

LOTTO 1 2 3 4 5 6

14 4 23 9 18 35

Which set of numbers is more likely to be thewinning combination?

HeuristicsRepresentativeness

(1) people try to apply their knowledge of a process to generate possible answers or judge the likelihood of an event

LOTTO drawing: random process;people pick a number that appears more random (less orderly)

This error reflects an insensitivity to sample size.

HeuristicsRepresentativeness

(2) people apply their knowledge of a very large sample (population) to an event, focusing onthe similarities

Stereotypes (very general info about a group)irrelevant information (that fits a

stereotype)can influence judgements – to the extent

that important, relevant info is overlooked

Stereotypes80 people in room

60 medical doctors, 20 academics

H. R. is dressed in a coat and tie. His appearance is tidy. He is personable, and his communication is direct. He enjoys playing squash and likes driving BMWs.

L. J. is dressed in pants and a loose-fitting shirt. His appearance is a bit unkempt. He is personable, and his communication is long-winded. He enjoys reading mysteries and riding bicycles.

What is the probability that H. R. is a medical doctor?What is the probability that L. J. is a medical doctor?

Stereotypes

80 people in room60 medical doctors20 academics

The extra info biases one’s estimate of an individual being a doctor or an academic. (Basically, info that fits with a stereotype is misapplied to an individual.)

HeuristicsRepresentativenessAvailabilitySimulation

HeuristicsAvailability highly accessible info influences judgments

Frequency biasmemory for relative frequencies of different types of info can be quite good under controlled conditions

in the real world, though, a person’s viewscan influence how he/she encodes events

confirmation bias; frequencies of events in memory may be inaccurate

Familiarity bias

how familiar info is influences judgements(research often done with famous and nonfamous names); people overestimate likelihoods based on fame/familiarity

Salience (Vividness) bias

big events (or events with lots of remembered details) influence judgments; people overestimate likelihoods based on big events

HeuristicsRepresentativenessAvailabilitySimulation

HeuristicsSimulation

application of a change in a sequence ofevents shifts the outcome (or probabilityfor that outcome) of the event

Undoing heuristictypically a less usual event is changedto a more usual event; downhill change

far less likely, a usual event is changedto a less usual event; uphill change

HeuristicsSimulation

application of a change in a sequence ofevents shifts the outcome (or probabilityfor that outcome) of the event

Focus rulechanges more likely to be made aroundthe subject of focus

HeuristicsSimulation

application of a change in a sequence ofevents shifts the outcome (or probabilityfor that outcome) of the event

Hindsightevent seems more likely after the fact

Anticipation of eventsthought of favourable outcomes blindsus to negative outcomes;leads to overestimation of a positive outcome

HeuristicsRepresentativenessAvailabilitySimulation

Problem solvingGestalt influenceInsightFunctional fixednessEinstellungAnalogies

Problem solvingGestalt influence

early research on “insight” -- chimp

Later research on humanssubjective experience of insight

different from other problem solving

solution comes all of a sudden in insightsolution feels like it comes more gradually

with other problems (e.g., algebra)

(see “warm” ratings in Goldstein)

Draw a continuous line with no curves and no more

than 4 segments to connect all of the dots

Draw a continuous line with no curves and no more

than 4 segments to connect all of the dots

Draw a continuous line with no curves and no more

than 4 segments to connect all of the dots

Draw a continuous line with no curves and no more

than 4 segments to connect all of the dots

Draw a continuous line with no curves and no more

than 4 segments to connect all of the dots

Problem solvingProblems associated with problem solving

Functional fixedness(solution) is slowed or prevented by a focus on objects usual function

a solution may require the novel application of an object

Problem solving

Need 100 liters of H2O.

Have 3 containers of which the capacity is known

Container A = 21 litersContainer B = 127 litersContainer C = 3 liters

How to measure out 100 liters?

Problem solving

Need 100 liters of H2O

Have 3 containers of which the capacity is known

Container A = 21 litersContainer B = 127 litersContainer C = 3 liters

How to measure out 100 liters? B – C – C – A

Problem solving

Need 18 liters of H2O

Have 3 containers of which the capacity is known

Container A = 15 litersContainer B = 39 litersContainer C = 3 liters

How to measure out 18 liters?

Problem solving

Need 18 liters of H2O

Have 3 containers of which the capacity is known

Container A = 15 litersContainer B = 39 litersContainer C = 3 liters

How to measure out 18 liters?B – C – C – A

Problem solving

Need 22 liters of H2O

Have 3 containers of which the capacity is known

Container A = 18 litersContainer B = 48 litersContainer C = 4 liters

How to measure out 22 liters?

Problem solving

Need 22 liters of H2O

Have 3 containers of which the capacity is known

Container A = 18 litersContainer B = 48 litersContainer C = 4 liters

How to measure out 22 liters?B – C – C – A

Problem solving

Need 25 liters of H2O

Have 3 containers of which the capacity is known

Container A = 28 litersContainer B = 76 litersContainer C = 3 liters

How to measure out 25 liters?

Problem solving

Einstellung – “mind set”approach to a problem

Set effects (or negative set effects) use of a set approach impedes

performance

HeuristicsRepresentativenessAvailabilitySimulation

Problem solvingGestalt influenceInsightFunctional fixednessEinstellungAnalogies (see Goldstein)

End

Have a good day!Thank you for a terrific trimester!