Based on research by Garrett, B. L. (2011), Steblay, N.K., Wells, G.L., and Douglass, A.B. (2014), and Wells, G. L., & Bradfield, A. L. (1998) written by Mara Rowcliffe, MS.
Is asking an eyewitness, “How certain are you in your identification?” a sound way to evaluate the reliability of their testimony? Is it trustworthy?
Psychologist Gary Wells and colleagues explored the ways in which giving feedback after a lineup can distort the witness’s memory. They examined 23 studies involving 7,000 participants from the United States, Canada, Australia and Europe. The results showed that when a lineup administrator confirms the witness’s choice, the witness’s confidence in that judgment is inflated and they reported afterwards that they had more ease, were quicker at identifying the person, and had more clarity. — a consequence that could later portray a level of certainty and thus distort their testimony of their actual experience.
A recent analysis of 161 DNA exoneration cases indicated 57% were mistakes of witnesses who testified confidently at the trial, but who had been substantially uncertain at their initial identification.
No, an eyewitness’ certainty should not be used to determine judge or jury decisions. The researchers concluded that, instead, allowing videotaping of a witnesses’ initial testimony before giving feedback, might lead to a more accurate impression, and thus a fairer judicial decision.
Garrett, B. L. (2011). Convicting the innocent: Where criminal prosecutions go wrong. Cambridge, MA: Harvard University Press.
Steblay, N.K., Wells, G.L., and Douglass, A.B. (2014). Eyewitness post identification feedback effect 15 years later: Theoretical and policy implications. Psychology, Public Policy, and Law (20)1, 1-18.
Wells, G. L., & Bradfield, A. L. (1998). “Good, you identified the suspect:” Feedback to eyewitnesses distorts their reports of the witnessing experience. Journal of Applied Psychology, 83, 360–376. doi: 10.1037/0021-9010.83.3.360