Representativeness heuristic
The representativeness heuristic is a heuristic judgment (decision rule), in which the probability of events will be judged on how closely they correspond to certain prototypes.
In a classic study offered Daniel Kahneman and Amos Tversky (1983 ) their subjects, the written description of a woman named Linda dar. It reported a lot about Linda's work for women's rights and emancipation. Then the subjects were asked what according to this description, unless more likely that Linda " a bank teller " or " a bank teller and feminist " is. The majority of the subjects estimated the probability that Linda " bank teller and feminist " is much higher one ( Konjunktionseffekt ).
However, this assessment is wrong, because the probability of the simultaneous occurrence of both events can not be greater than the probability that one of two things happens alone. Even if all the bank employees are also feminists who would be the two probabilities for ( 1) " bank employees " and (2) " bank teller and feminist " equal.
Another important study by Kahneman & Tversky (1973 ) demonstrated the occurrence of the so-called base -rate error ( error prevalence or base rate neglect ). In this case, the subjects of two groups were presented brief descriptions that were with the stereotype of the " legal " or " Engineer" compatible ( for example, " Jack is 45 years old. He is married and has four children. He is generally conservative, careful and ambitious. He is not interested in politics or social issues, and uses most of his spare time on one of his many hobbies such as carpentry, sailing and mathematical brain teasers. "). The base rate was varied by trial participants were informed that these persons description results from interviews with 30 lawyers and 70 engineers have undergone. Task of the subjects was to assess how likely it is an engineer (or legal ) acts. The different output probabilities had little influence on the verdict, because the subjects due to the external description prepares an assignment. It often came therefore to judgment errors.
The base rate neglect, that is, the over-estimation of the conditional probability of events with a low base rate, Kahneman and Tversky explain the application of the representativeness heuristic. More recent explanations for this error in judgment process can be found in Gigerenzer & Hoffrage ( 1995) ( presentation format ) and Fiedler et al. (2000) ( sampling effect).
Swell
- Tversky, A. & Kahneman, D. ( 1973). Availability: A heuristic for judging frequency and probability. Cognitive Psychology, 42, 207-232.
- Gigerenzer, G. & Hoffrage, U. ( 1995). How to Improve bayesian reasoning without instruction: Frequency formats. Psychological Review, 102, 684-704.
- Fiedler, K., Brinkmann, B., Betsch, T. & Wild, B. ( 2000). A Sampling Approach to Biases in Conditional Probability Judgments: Beyond base rate neglect and statistical format. Journal of Experimental Psychology: General, 129 ( 3), 399-418.