Abstract
under uncertainty has revealed that people judge the probability of an event to be higher when the event is described as a disjunction of constituent events or when they judge constituent events separately. These observations have motivated the development of support theory (Y. Rottenstreich & A. Tversky, 1997; A. Tversky & D. J. Koehler, 1994), a descriptive model of judgment under uncertainty. The major predictions of support theory are that (1) the judged probabilities of complementary events sum to 1; (2) the judged probabilities of n > 2 exclusive and exhaustive events generally sum to more than 1; and (3) the judged probability of an event generally increases when it is described as a disjunction of specific possibilities. We test these predictions in 6 studies of experienced attorneys who judged the likelihood of particular trial outcomes or were asked to offer advice on whether or not to accept a settlement offer. The results demonstrate that attorneys are indeed susceptible to bias in forecasting trial outcomes, consistent with support theory.
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REFERENCES
Arkes, H. R. (1991). Costs and benefits of judgment errors: Implications for Debiasing. Psychological Bulletin, 110, 486–498.
Bearden, N.,Wallsten, T., & Fox, C. R. (2001). Constrasting stochastic and support theory explanations of subadditivity. Manuscript in preparation.
Birke, R., & Fox, C. R. (1999). Psychological principles in negotiating civil settlements. Harvard Negotiation Law Review, 4, 1–57.
Fischhoff, B., Slovic, P., & Lichtenstein, S. (1978). Fault trees: Sensitivity of estimated failure probabilities to problem representation. Journal of Experimental Psychology: HumanPerception and Performance, 4, 330–344.
Fox, C. R. (1999). Strength of evidence, judged probability, and choice under uncertainty. Cognitive Psychology, 38, 167–189.
Fox, C. R., Rogers, B. A., & Tversky, A. (1996). Options traders exhibit subadditive decision weights. Journal of Risk and Uncertainty, 13, 5–17.
Fox, C. R., & Tversky, A. (1998). A belief-based account of decision under uncertainty. Management Science, 44, 879–895.
Guthrie, C., Rachlinsky, J. J., & Wistrich, A. J. (2001). Inside the judicial mind. Cornell Law Review, 86, 777–830.
Kahneman, D., Slovic, P., & Tversky, A. (Eds.). (1982). Judgment under uncertainty: Heuristics and biases. Cambridge, England: Cambridge University Press.
Loewenstein, G., Isaacharoff, S., Camerer, C. F., & Babcock, L. (1993). Self-serving assesments of fairness and pretrial bargaining. Journal of Legal Studies, 22, 135–159.
Lord, C. G., Ross, L., & Lepper, M. R. (1979). Biased assimilation and attitude polarization: The effects of prior theories on subsequently considered evidence. Journal of Personality and Social Psychology, 37, 2098–2109.
Redelmeier, D., Koehler, D. J., Liberman, V., & Tversky, A. (1995). Probability judgment in medicine: Discounting unspecified possibilities. Medical Decision Making, 15, 227–230.
Rottenstreich, Y., & Tversky, A. (1997). Unpacking, repacking, and anchoring: Advances in support theory. Psychological Review, 104, 406–415.
Taylor, S. E., & Brown, J. D. (1988). Illusion and well-being: A social psychological perspective on mental health. Psychological Bulletin, 103, 193–210.
Teigen, K. H. (1974). Subjective sampling distributions and the additivity of estimates. Scandinavian Journal of Psychology, 24, 97–105.
Tversky, A., & Kahneman, D. (1983). Extensional vs. intuitive reasoning: The conjunction fallacy in probability judgment. Psychological Review, 91, 293–315.
Tversky, A., & Koehler, D. J. (1994). Support theory: A nonextensional representation of subjective probability. Psychological Review, 101, 547–567.
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Fox, C.R., Birke, R. Forecasting Trial Outcomes: Lawyers Assign Higher Probability to Possibilities That Are Described in Greater Detail. Law Hum Behav 26, 159–173 (2002). https://doi.org/10.1023/A:1014687809032
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DOI: https://doi.org/10.1023/A:1014687809032