Eyewitness Testimony


        It is often argued that despite the limitations of human information processing, jurors overestimate the validity of eyewitness testimony because they are unaware of all the factors that can compromise an eyewitness' accuracy. For example, jurors may be unaware of the factors that can interfere with eyewitness perception, such as the weapons focus effect, or factors that interfere with memory storage, such as the effect of prior exposures on suspect identification (Cutler, Penrod, & Dexter, 1990). Previous research finding demonstrate that jurors overestimate the accuracy of eyewitnesses.  To illustrate this point, in one study mock jurors were presented with a case of an armed robbery that resulted in two deaths (Loftus, 1974). Eighteen percent of the mock jurors, who heard only circumstantial evidence, convicted the defendant. However, 72% of the mock jurors who heard eyewitness testimony in addition to circumstantial evidence convicted the defendant. Even when the eyewitness had 20/400 vision, 68% found the defendant guilty.

In addition, jurors already have a difficult time weighing the strength of a positive identification because of procedural safeguards.  For example, if other eyewitness were unable to identify the defendant jurors will not be told about it (Wells & Lindsay, 1980).  Given this possible initial setback, one implication is that jurors should have the benefit of hearing an psychological expert evaluate the eyewitness identification for weakness.

For a critical exegesis of the use of psychological testimony in the courtroom, I highly suggest this article:  Eyewitness Memory Research:  Probative versus Prejudicial Value   (Ebbesen & Konecni, 1996).

References

Cutler, B.L., Penrod, S.D., & Dexter, H.R. (1990). Juror sensitivity to eyewitness identification evidence. Law and Human Behavior, 14, 185-192.

Hastie, R. (1980). From eyewitness testimony to unreasonable doubt. Unpublished manuscript. In L.S. Wrightman, M.T. Nietzel and W.H. Fortune, Psychology and the legal system. Belmont, CA: Wadsworth.

Loftus, E.F. (1974). Reconstructing memory: The incredible witness. Psychology Today, 8, 116-119.

Wells, G.L., & Lindsay, R.C.L. (1980). On estimating the diagnosticity of eyewitness nonidentification. Psychological Bulletin, 88, 776-784.

Wells, G.L., Lindsay, R.C.L., & Ferguson, T.J. (1979). Accuracy, confidence, and juror perceptions in eyewitness identification. Journal of Applied Psychology, 64, 440-448.
 

Return to Eyewitness Identification page

Return to Home page