Abstract
In this paper we examine evidence for two potential descriptions of juror reactions to probabilistic DNA evidence. The error-based description posits that jurors commit systematic logical or mathematical errors when they are called upon to evaluate quantitative evidence. The expectancy-based description posits that jurors use their background knowledge and beliefs in evaluating results from scientific tests. Consistent with the error-based description, participants in our study incorrectly aggregated separately presented probabilities and afforded probabilistic evidence less weight than would be expected by applying Bayesian norms. Consistent with the expectancy-based description, participants' background beliefs about the possibility of laboratory errors and intentional tampering affected the weight participants afforded a DNA match report. We discuss potential implications of these findings for the legal system and suggest directions for future research.
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REFERENCES
Bernstein, D. E. (1996). Junk science in the United States and the Commonwealth. Yale Journal of International Law, 21, 123-182.
Collins, R., Taylor, S., Wood, J., & Thompson, S. (1988). The vividness effect: Elusive or illusory? Journal of Experimental Social Psychology, 24, 1-18.
Commonwealth v. Curnin, 565 N.E. 2d 440, 441 (Mass. 1991).
Connors, E., Lundregan, T., Miller, N., & McEwen, T. (1996). Convicted by juries and exonerated by science: Case studies in the use of DNA evidence to establish innocence at trial. National Institute of Justice Research Report No. NCJ 161258.
Dellios, H. (1995, September 18). U.S. justice system hit by Simpson trial fallout. The Chicago Tribune, pp. A1, A10.
Diamond, S. S. (1997). Illuminations and shadows from jury simulations. Law and Human Behavior, 21, 561-571.
Diamond, S. S., & Casper, J. D. (1992). Blindfolding the jury to verdict consequences: Damages, experts, and the civil jury. Law & Society Review, 26, 513-563.
Diamond, S. S., & Levi, J. N. (1996). Improving instructions on death by revising and testing jury instructions. Judicature, 79, 224-232.
DuCharme, W. (1970). Response bias explanation of conservative human inference. Journal of Experimental Psychology, 85, 66-74.
Ellsworth, P. C. (1989). Are twelve heads better than one? Law and Contemporary Problems, 52, 205-224.
Faigman, D., & Baglioni, A. (1988). Bayes' theorem in the trial process. Law and Human Behavior, 12, 1-17.
Fong, G. T., Lurigio, A. J., & Stalans, L. J. (1989). Improving probation decisions through statistical training. Criminal Justice and Behavior, 17, 370-388.
Funder, D. (1987). Errors and mistakes: Evaluating the accuracy of social judgment. Psychological Bulletin, 101, 75-90.
Goodman J. (1992). Jurors' comprehension and assessment of probabilistic evidence. American Journal of Trial Advocacy, 16, 361-389.
Hanita, M., Gavanski, I., & Fazio, R. H. (1997). Influencing probability judgments by manipulating the accessibility of sample spaces. Personality and Social Psychology Bulletin, 23, 801-813.
Hastie, R., Penrod, S. D., & Pennington, N. (1983). Inside the jury. Cambridge, MA: Harvard University Press.
Hays, W. L. (1994). Statistics (5th ed.). Fort Worth, TX: Harcourt Brace.
Huber, P. W. (1991). Galileo's revenge: Junk science in the courtroom. New York: Basic Books.
Imwinkelried, E. (1982–1983). The standard for admitting scientific evidence: A critique from the perspective of juror psychology. Villanova Law Review, 28, 554-571.
Kalven, H., & Zeisel, H. (1966). The American jury. Chicago, IL: University of Chicago Press.
Koehler, J. J. (1993). Error and exaggeration in the presentation of DNA evidence at trial. Jurimetrics Journal, 34, 21-39.
Koehler, J. J. (1997). Why DNA likelihood ratios should account for error (even when a National Research Council Report says they should not). Jurimetrics Journal, 37, 425-437.
Koehler, J. J., Chia, A., & Lindsay, S. (1995). The random match probability in DNA evidence: Irrelevant and prejudicial? Jurimetrics Journal, 35, 33-58.
Landsman, S., & Rakos, R. F. (1994). A preliminary inquiry into the effect of potentially biasing information on judges and jurors in civil litigation. Behavioral Sciences and the Law, 12, 113-126.
Lempert, R. (1993). DNA, science, and the law: Two cheers for the ceiling principle. Jurimetrics Journal, 34, 41-57.
MacCoun, R., & Kerr, N. (1988). Asymmetric influence in mock jury deliberation: Jurors' bias for leniency. Journal of Personality and Social Psychology, 54, 21-33.
National Research Council Report. (1992). DNA technology in forensic science. Washington, DC: National Academy Press.
National Research Council Report. (1996). Report on the evaluation of forensic DNA evidence. Washington, DC: National Academy Press.
Nisbett, R., & Ross, L. (1980). Human inference: Strategies and shortcomings of social judgment. Englewood Cliffs, NJ: Prentice-Hall.
People v. Collins, 68 Cal. 2d 319 (1968).
Peterson, J. L., Ryan, J. P., Houlden, P. J., & Mihajlovic, S. (1987). The uses and effects of forensic science in the adjudication of felony cases. Journal of Forensic Sciences, 32, 1730-1753.
Sanders, J. (1993). From science to evidence: The testimony on causation in the Bendectin cases. Stanford Law Review, 46, 1-86.
Saks, M., & Kidd, R. (1980). Human information processing and adjudication: Trial by heuristics. Law & Society Review, 15, 123-160.
Schklar, J. (1996, March). Naive beliefs about science and reactions to DNA evidence. Paper presented at the 1996 American Psychology—Law Society Biennial Conference in Hilton Head, South Carolina.
Schklar, J. (1996, July). Juror reactions to DNA evidence: Misperception and misaggregation. Paper presented at the 1996 Law and Society Conference in Glasgow, Scotland.
Smith, B. C., Penrod, S. D., Otto, A. L., & Park, R. C. (1996). Jurors' use of probabilistic evidence. Law and Human Behavior, 20, 49-82.
Taylor, S., & Thompson, S. (1982). Stalking the elusive vividness effect. Psychological Review, 89, 155-181.
Thompson, W. C. (1993). Evaluating the admissibility of new genetic identification tests: Lessons from the “DNA war.” Journal of Criminal Law and Criminology, 84, 22-104.
Thompson, W. C., & Schumann, E. (1987). Interpretation of statistical evidence in criminal trials. Law and Human Behavior, 11, 167-187.
Tribe, L. (1971). Trial by mathematics: Precision and ritual in the legal process. Harvard Law Review, 84, 1329-1376.
Tribune News Services. (1997, November 13). DNA analysis now can leave no doubt, FBI reports. Chicago Tribune, p. A15.
United States v Addison, 498 F. 2d 741 (1974).
Wells, G. L. (1992). Naked statistical evidence of liability: Is subjective probability enough? Journal of Personality and Social Psychology, 62, 739-752.
Wilson, T., & Brekke, N. (1994). Mental contamination and mental correction: Unwanted thought influences on judgments and evaluations. Psychological Bulletin, 116, 117-142.
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Schklar, J., Diamond, S.S. Juror Reactions to DNA Evidence: Errors and Expectancies. Law Hum Behav 23, 159–184 (1999). https://doi.org/10.1023/A:1022368801333
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DOI: https://doi.org/10.1023/A:1022368801333