Expert Psychological Testimony Empirical and Conceptual Analyses of Effects

Experimental psychologists increasingly are asked to give expert testimony in court, especially with regard to issues of eyewitness reliability. Whether or not experimental psychologists should give expert testimony on these matters is a controversial issue. The empirical literature suggests that potential jurors do not have a good understanding of the variables influencing eyewitness accuracy and that they cannot discriminate adequately between accurate and false eyewitness identification testimony. Experiments using expert testimony as a treatment variable, however, have not made a definitive case that expert testimony can benefit trial outcomes. The question of whether or not to give expert testimony must be broadened to consider not only the effects on verdicts but also the effects of expert testimony on the process by which verdicts are reached, the practices of police in subsequent investigations, the public's view of psychology, the practices of judges in subsequent cases, and the interaction between expert testimony and research activities.