Cognitive Accessibility & Heuristics
Decision-Making
Judgment Heuristics: mental shortcuts that enables a quick and intuitive answer to a problem
Cognitive Accessibility: thoughts that spring to mind rapidly, effortlessly, and spontaneously; intuitions
Availability: judgment of probability/frequency based on the ease with which instances or occurrences can be brought to mind
Anchoring: initially suggested (but irrelevant) piece of numerical information (the anchor) serves as an implicit standard of comparison which biases later judgment
Representativeness: judgment of probability/frequency based on similarity/representativeness
Framing Effects
Surgery or Radiation?
Custody of Child
Save or Die?
Neglect of Base-Rates
Order of Births
Representativeness + Availability
Seven Letter Words
List of Famous People
Coin Tosses
Carter or Ford
Medicine: recently seen patients can bias judgment
Linda Problem
"No-Stats All Star"
Blind Auditions
African Nations in the U.N.
SSN & Physicians in Manhattan
IV: 200/600 people will be saved vs 400/600 people will die
DV: choice between logically equivalent information
Results: different reference/comparison points
IV: 90% survival vs 10% mortality
DV: attitude toward surgery vs radiation
Results: favorable to surgery when framed in terms of survival; unfavorable to surgery when framed in terms of mortality
IV: average parent vs extreme parent (good and bad)
DV: award/deny custody of child
Results: extreme parent (good and bad) awarded and denied custody
Conclusions: reason-based choice
Results: logical error; conjunction fallacy that specific conditions are more probable than a general one
Conclusions: judgment of probability conflated with a judgment of representativeness
Results: judgment of frequency distorted by whether the sequence "fits with" or is "representative of" people's image of randomness
IVs
Representativeness: how representative Tom W. to a typical student in each field?
Likelihood: how likely Tom W. a student in each field?
Base-Rate: % of students enrolled in each field
Results: correlation between likelihood & representativeness = 0.97
Results: correlation between likelihood & base-rate = -0.65
Conclusions: over-reliance on a stereotype; discounting of base-rate information
IV: "_n_" vs "____ing"
DV: estimate number of words
Results: more words estimated in "____ing"
Conclusions: judgment of frequency distorted by what information is most available in mind
IV: list contains more men, but women are more famous vs list contains more women, but men are more famous
DV: more men or women in list?
Results: judged to be more people from the famous category
IV: imagine Carter or Ford having won
DV: predict results of election
Results: "imagined" candidate judged more likely to win
Sports: judgments of future performance biased by fit of a player to a prototype
Conclusions: recently active and vivid thoughts are more available and bias probability judgments
Representativeness: does not fit prototype
Availability: less visible, less accessible things
Representativeness: does not fit biased prototype
Availability: sex is more accessible/available than true skill, and is easier to judge
IV: greater or less than... low anchor (10%) vs high anchor (65%)
DV: % of African nations in U.N.
IV: greater or less than... anchor (SSN) vs no anchor
DV: # of physicians in Manhattan
Results: correlation between SSN and estimates = 0.4; correlation when anchor asked second = 0
Results: low anchor = 25%; high anchor = 45%
Conclusions: initial anchor is accessible and biases later judgment