| Chapter 6 Representativeness heuristic: We rely on the similarity between our conceptions of a category and our impression of the object/person/situation to make our judgments We assume that a member of a category should be representative of all the other instances in that category Basis for stereotypes Leads to ignore relevant base rate information when other information is given, even if the latter is recognized as being nonpredictive Leads to missing the logical structure of the problem Conjunction fallacy: the conjunction of two events cannot be more likely than either event alone As the amount of details increases the representativeness of the event increases as well as it makes it more life-like, but the probability can only decrease Leads to ignore sample size Law of small numbers: incorrectly assume that small samples are as representative of the population as large samples Knowing the basic laws of probability is useful to think logically Confusion of the inverse: wrongly assuming that the probability of A knowing B is the same as the probability of B knowing A Should rely on ratio rule: p(A/B) x p(B) = p(B/A) x p(A) The use of heuristics is automatic; in order to counteract it we have to think about the base rates associated with a certain event: "How prevalent is this category?" |
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