This study examined the influence of expert witness testimony and jury instructions on mock jurors\u27 final verdicts of guilt in a case where the sole eyewitness to a murder/abduction was a five-year-old-child. One hundred and ninety-two college students heard an audio-taped trial proceeding in which the testimony of an expert witness and the jury instructions were varied (both supporting or discrediting of a child witness\u27 testimony or mixed testimonies). Individual judgments of guilt and judgments after group deliberation were recorded. It was hypothesized that expert witness testimony and jury instructions would significantly influence verdicts. Contrary to predictions, neither expert witness testimony nor judge\u27s jury instructions influenced individual ratings of guilt, group directions, or time spent in deliberation. It was found that when a supporting expert witness was paired with a supporting judge the individual guilty rates were higher than when a supporting expert witness was paired with a discrediting judge. Only 37% of the groups reached a mutual decision, with groups who heard congruent supportive messages significantly less likely to reach a mutual decision than those groups who heard congruent discrediting messages. These letter groups were significantly more likely to reach a mutual decision. Implications for future research are discussed
