Impact of expert psychological testimony on the unreliability of eyewitness identification.

Abstract

The purpose of the present research was to study the influence on jurors ofexpert testimony about eyewitness identification. In Experiment 1 240 students(all registered voters) acted as jurors and received evidence against a defendantin a violent or a nonviolent case. The major piece of prosecution evidencewas the testimony of the eyewitness. Half of the jurors read about the testimonyof a defense expert on the reliability of eyewitness identification, whereas halfdid not. Individual verdicts were reached. The results indicated that therewere fewer convictions when expert testimony was permitted. In Experiment2 120 students received evidence in a hypothetical violent crime and thendeliberated injuries of 6 to reach a verdict for or against the defendant. Jurorswho had read about the expert testimony spent much more time discussingthe eyewitness account than did jurors who had not been presented with experttestimony. The results indicate that one consequence of presenting psychologi-cal expert testimony is an increase in the amount of attention that jurors giveto eyewitness accounts, perhaps enhancing their scrutinization. Some pros andcons of the psychological expert testimony are discussed.