Dateline: April, 2008, Issue 1
Exposing inconsistencies in a witness' testimony can affect verdicts, but not always.
Berman and Cutler (1996) investigated the exposure of inconsistencies in testimony through cross-examination of a prosecution eyewitness. Defense attorney cross-examination that exposed inconsistencies in testimony reduced rates of conviction.
Berman and colleagues (1995) found that exposing inconsistencies reduced conviction rates even when the inconsistencies dealt with peripheral rather than central case facts.
The exposure of inconsistencies in a witness' testimony does not always influence verdicts, however.
Brewer and Burke (2002) found that the confidence of a witness was a more important influence on jurors' verdicts than the consistency of a witness. Jurors seldom gave guilty verdicts when faced with a non-confident prosecution witness, regardless whether the testimony was consistent or inconsistent.
In sum, inconsistent testimony is not as compelling to jurors when the witness maintains confidence, and consistent testimony is not as compelling to jurors when the witness lacks confidence.
Source Berman, G. L. & Cutler, B. L. (1996). Effects of inconsistencies in eyewitness testimony on mock-juror decision making. Journal of Applied Psychology, 81, pp. 170-177.
Source Berman, G. L., Narby, D. J., & Cutler, B. L. (1995). Effects of inconsistent eyewitness statements on mock-jurors' evaluations of the eyewitness, perceptions of defendant culpability, and verdicts. Law and Human Behavior, 19, pp. 79-88.
Source Brewer, N. & Burke, A. (2002). Effects of testimonial inconsistencies and eyewitness confidence on mock-juror judgments. Law and Human Behavior, 26, pp. 353-364.