Eyewitness testimony: the dangers of guessing

In Experiment 1, college students watched a series of slides depicting a street crime. Some of the subjects were then asked a series of questions and they were urged to guess at the answers if they were uncertain. Relative to control subjects, those who guessed were more likely to commit false alarm errors on a final test given later on. Experiment 2 showed that the confidence level of a person who guesses about a detail can rise over time rather than decline. It is argued that guessing can cause a change in a person's memorial representation?guesses can fill in a vague and schematic representation making it more vivid. These results have implications for the conduct of police and courtroom interrogation procedures. Psychologists have addressed the problem of evaluating the validity of eyewitness testimony since the earliest days of experimental research on human memory. Generally, researchers have concluded that eyewitness reports provide a delicate, unreliable route to historical truth. Numerous sources of error and failure have been revealed by research mimicking the conditions obtained in natural eyewitness situations.1 The conditions under which the eyewitness is interrogated provide one of the major sources of threats to testimony validity. These condi? tions are under the control of legal and police authorities. A far from rare practice involves, in essence, asking a witness who is not quite