The External Validity of Eyewitness Identification Research: Generalizing Across Subject Populations

The propriety of psychological testimony concerning factors that influence eyewitness reliability has been challenged on the grounds that the research methods and populations used in eyewitness research may not generalize. The present experiment examines one aspect of the generalizability issue and tests whether a number of factors that have produced differential performance in college-age subject populations produce similar effects in older subject populations. Subjects ranging from 18 to 74 years of age viewed a videotaped reenactment of a robbery. In the videotapes the presence of a weapon and the robber's disguise were manipulated. At the identification phase, the presence of the robber in the lineup, the lineup instructions given the witnesses, and contextual aids to witness memory were manipulated. Age produced a main effect on identification accuracy (with performance declining with age), but did not interact with any of the other variables. The results indicate that the effects of the other independent variables generalize across age groups.