Greene, E. (1988). Judge’s instruction on eyewitness testimony: Evaluation and revision. Journal of Applied Social Psychology, 18, 252-276.
Studies of the reliability of eyewitness identification show that such testimony may frequently be inaccurate; because of this inherent unreliability, the law has established certain safeguards to the use of eyewitness evidence. One safeguard has been the development of an instruction that a judge may use to focus jurors’ attention on the eyewitness issue. The effectiveness of this instruction has never been assessed, although other studies confirm that jurors frequently misunderstand or incorrectly use instructions they get from the judge. The purpose of these studies was to evaluate comprehension of this instruction in the context of a videotaped trial and to develop a simplified instruction that would be easier for jurors to understand. Compared to jurors who heard the existing instruction, those with the revised version were more knowledgeable of the factors to consider when listening to eyewitness testimony and were less likely to convict the defendant. A sample of superior court judges in the U.S. thought the simplified instruction was more effective than the existing version at conveying the intended legal concepts to the jury, but also rated it as more strongly biased toward the defense.
Weak effect of evidence strength (defendant identification) in both studies. <1>Jurors receiving pattern instruction on eyewitness reliability no more knowledgeable than those who did not. <2>Jurors exposed to simplified instruction showed only slightly better comprehension of content.