Memory & Cognition

, Volume 28, Issue 1, pp 79–91 | Cite as

Not only base rates are neglected in the Engineer-Lawyer problem: An investigation of reasoners’ underutilization of complementarity

  • Jean BaratginEmail author
  • Ira A. Noveck


The standard Engineer-Lawyer problem (Kahneman & Tversky, 1973) points to the failure of reasoners to integrate mentioned base-rate information in arriving at likelihood estimates. Research in this area nevertheless has presupposed that participants respect complementarity (i.e., participants ensure that competing estimates add up to 100%). A survey of the literature leads us to doubt this presupposition. We propose that the participants’ non-normative performance on the standard Engineer- Lawyer problem reflects a reluctance to view the task probabilistically and that normative responses become more prominent as probabilistic aspects of the task do. In the present experiments, we manipulated two kinds of probabilistic cues and determined the extent to which (1) base rates were integrated and (2) the complementarity constraint was respected. In Experiment 1, six versions of an Engineer-Lawyer-type problem (that varied three levels of cue to complementarity and two base rates) were presented. The results showed that base-rate integration increased as cues to complementarity did. Experiment 2 confirmed that Gigerenzer, Hell, and Blank’s (1988) random-draw paradigm facilitates base-rate integration; a second measure revealed that it also prompts respect for complementarity. In Experiment 3, we replicated two of our main findings in one procedure while controlling for the potential influence of extraneous task features. We discuss approaches that describe how probabilistic cues might prompt normative responding.


Base Rate Mathematics Teacher Subjective Probability Confidence Judgment Complementarity Condition 
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  1. Alberoni, F. (1962). Contribution to the study of subjective probability: Part I.Journal of General Psychology,66, 241–264.CrossRefPubMedGoogle Scholar
  2. Asare, S. K., &Wright, A. (1995). Normative and substantive exper tise in multiple hypotheses evaluation.Organizational Behavior & Human Decision Processes,3, 171–184.CrossRefGoogle Scholar
  3. Braine, M. D. S., Connell, J., Freitag, J., &O’Brien, D. P. (1990). Is the base rate fallacy an instance of asserting the consequent? In K. L. Gilhooly, M. T. G. Leane, R. H. Logie, & G. Erdos (Eds.),Lines of thinking: Reflections on the psychology of thought (Vol. 1, pp. 165–180). New York: Wiley.Google Scholar
  4. Carroll, G. S., &Siegler, R. S. (1977). Strategies for the use of base rate information.Organizational Behavior & Human Performance,19, 392–402.CrossRefGoogle Scholar
  5. Cohen, J., Dearnaley, E. J., &Hansel, C. E. (1956). The addition of subjective probabilities.Acta Psychologica,12, 371–380.CrossRefGoogle Scholar
  6. Cosmides, L., &Tooby, J. (1996). Are humans good intuitive statisticians after all? Rethinking some conclusions from the literature on judgement under uncertainty.Cognition,58, 1–73.CrossRefGoogle Scholar
  7. Davidson, D., &Hirtle, S. C. (1990). Effects of nondiscrepant and discrepant information on the use of base rates.American Journal of Psychology,103, 343–357.CrossRefGoogle Scholar
  8. Einhorn, H. J., &Hogarth, R. M. (1985). Ambiguity and uncertainty in probabilistic inference.Psychological Review,92, 433–461.CrossRefGoogle Scholar
  9. Fischhoff, B., &Bar-Hillel, M. (1984). Diagnosticity and the baserate effect.Memory & Cognition,12, 402–410.CrossRefGoogle Scholar
  10. Gigerenzer, G. (1991). How to make cognitive illusions disappear: Beyond “heuristics and biases.”European Review of Social Psychology,2, 83–115.CrossRefGoogle Scholar
  11. Gigerenzer, G. (1993). The bounded rationality of probabilistic mental models. In K. I. Manktelow & D. E. Over (Eds.),Rationality (pp. 284–313). London: Routledge.Google Scholar
  12. Gigerenzer, G. (1994). Why the distinction between single-event probabilities and frequencies is important for psychology (and vice versa). In G. Wright & P. Ayton (Eds.),Subjective probability (pp. 129–162). New York: Wiley.Google Scholar
  13. Gigerenzer, G. (1996). On narrow norm and vague heuristics: A reply to Kahneman and Tversky.Psychological Review,103, 592–596.CrossRefGoogle Scholar
  14. Gigerenzer, G., Hell, W., &Blank, H. (1988). Presentation and content: The use of base rates as a continuous variable.Journal of Experimental Psychology: Human Perception & Performance,14, 513–525.CrossRefGoogle Scholar
  15. Gigerenzer, G., &Hoffrage, U. (1995). How to improve Bayesian reasoning without instruction: Frequency formats.Psychological Review,102, 684–704.CrossRefGoogle Scholar
  16. Gigerenzer, G., Swijtink, Z., Porter, T., Daston, L., Beatty, J., &Kruger, L. (1989).The empire of chance: How probability changed science and everyday life. Cambridge: Cambridge University Press.Google Scholar
  17. Ginosar, Z., &Trope, Y. (1980). The effects of base rates and individuating information on judgments about another person.Journal of Experimental Social Psychology,16, 228–242.CrossRefGoogle Scholar
  18. Girotto, V. (1994).Il Ragiomento. Bologna: Il Mulino.Google Scholar
  19. Griffin, D., & Dukeshire, S. (1992).On the use and neglect of base rates: A test of the visual random sampling hypothesis. Unpublished manuscript, University of Waterloo, Department of Psychology.Google Scholar
  20. Hertwig, R., &Gigerenzer, G. (1999). The “conjunction fallacy” revisited: How intelligent inferences look like reasoning errors.Journal of Behavioral Decision Making,12, 275–305.CrossRefGoogle Scholar
  21. Hilton, D. (1995). The social context of reasoning: Conversational inference and rational judgment.Psychological Bulletin,118, 248–271.CrossRefGoogle Scholar
  22. Jones, S. K., Jones, K. T., &Frisch, D. (1995). Biases of probability assessment: A comparison of frequency and single case judgments.Organizational Behavior & Decision Processes,2, 109–122.CrossRefGoogle Scholar
  23. Kahneman, D., &Tversky, A. (1972). Subjective probability: A judgment of representativeness.Cognitive Psychology,3, 430–453.CrossRefGoogle Scholar
  24. Kahneman, D., &Tversky, A. (1973). On the psychology of prediction.Psychological Review,80, 237–251.CrossRefGoogle Scholar
  25. Koehler, J. J. (1996). The base rate fallacy reconsidered: Descriptive, normative and methodological challenges.Behavioral & Brain Sciences,19, 1–53.CrossRefGoogle Scholar
  26. Krosnick, J. A., Li, F., &Lehman, D. R. (1990). Conversational conventions, order of information acquisition, and the effect of base rates and individuating information on social judgments.Journal of Personality & Social Psychology,59, 1140–1152.CrossRefGoogle Scholar
  27. Macchi, L. (1994). On the communication and comprehension of probabilistic information.Psycoloquy [On-line serial],5(11), base-rate. 11.macchi.Google Scholar
  28. Macchi, L. (1995). Pragmatic aspects of the base-rate fallacy.Quarterly Journal of Experimental Psychology,48A, 188–207.Google Scholar
  29. Marks, D. F., &Clarkson, J. K. (1972). An explanation of conservatism in the bookbag-and-pokerchips situations.Acta Psychologica,36, 145–160.CrossRefGoogle Scholar
  30. Noveck, I. A. (1997). Deductive competence need not be problematic: Some comments on Evan and Over’s proposal concerning human rationality.Current Psychology of Cognition,17, 162–172.Google Scholar
  31. Piatelli-Palmarini, M. (1993).L’illusione di sapere. Milan: Arnoldo Mondadori.Google Scholar
  32. Politzer, G., &Noveck, I. (1991). Are conjunction rule violations the result of conversational rule violations?Journal of Psycholinguistic Research,20, 83–103.CrossRefGoogle Scholar
  33. Schwarz, N., Strack, F., Hilton, D., &Naderer, G. (1991). Base rates, representativeness, and the logic of conversation: The contextual relevance of “irrelevant” information.Social Cognition,9, 67–83.CrossRefGoogle Scholar
  34. Slovic, P., Lichtenstein, S., &Fischhoff, B. (1988). Decision making. In R. Atkinson, R. J. Herrnstein, G. Lindzey, & R. D. Luce (Eds.),Stevens’s Handbook of experimental psychology, learning and cognition (Vol. 2, pp. 673–737). Cambridge: Cambridge University Press.Google Scholar
  35. Sperber, D., Cara, F., &Girotto, V. (1995). Relevance theory explains the selection task.Cognition,57, 31–95.CrossRefPubMedGoogle Scholar
  36. Sperber, D., &Wilson, D. (1995).Relevance: Communication & cognition (2nd ed.). Oxford: Blackwell. (1st ed. Cambridge, MA: Harvard University Press, 1986)Google Scholar
  37. Swieringa, R., Gibbins, M., Larsson, L., &Sweeney, J. L. (1976). Experiments in the heuristics of human information processing.Journal of Accounting Research,14 (Suppl.), 159–187.CrossRefGoogle Scholar
  38. Teigen, K. H. (1974). Overestimation of subjective probabilities.Scandinavian Journal of Psychology,15, 56–62.CrossRefGoogle Scholar
  39. Teigen, K. H. (1983). Studies in subjective probability III: The unimportance of alternatives.Scandinavian Journal of Psychology,24, 97–105.CrossRefGoogle Scholar
  40. Tversky, A., &Kahneman, D. (1982). Evidential impact of base rates. In D. Kahneman, P. Slovic, & A. Tversky (Eds.),Judgment under uncertainty: Heuristics and biases (pp. 153–160). Cambridge: Cambridge University Press.Google Scholar
  41. Van Wallendael, L. R., &Hastie, R. (1990). Tracing the footsteps of Sherlock Holmes: Cognitive representations of hypothesis testing.Memory & Cognition,18, 240–250.CrossRefGoogle Scholar
  42. Von Winterfeldt, D., &Edwards, W. (1986).Decision analysis and behavioral research. Cambridge: Cambridge University Press.Google Scholar
  43. Wells, G. L., &Harvey, J. H. (1978). Naive attributors’ attributions and predictions: What is informative and when is an effect an effect?Journal of Personality & Social Psychology,36, 483–490.CrossRefGoogle Scholar
  44. Zukier, H., &Pepitone, A. (1984). Social roles and strategies in prediction: Some determinants of the use of base-rate information.Journal of Personality & Social Psychology,47, 349–360.CrossRefGoogle Scholar

Copyright information

© Psychonomic Society, Inc. 2000

Authors and Affiliations

  1. 1.Université de Grenoble IIGrenobleFrance
  2. 2.CREAécole PolytechniqueParisFrance

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