Effects of the type of incident and the number of perpetrators on eyewitness memory.

The accuracy of eyewitness testimony and identification following the unprepared witnessing of either a violent (mugging) or a nonviolent (direction seeking) videotaped incident in which one, three, or five perpetrators participated was investigated, together with the relationship between the witnesses' objective accuracy and their subjective feeling of certainty concerning correctness. Sixty subjects, 30 male and 30 female unpaid undergraduates with an average age of 21.7 years, were tested individually. Testimony was less accurate following the witnessing of the violent incident, and the decrease in accuracy was a function of the increase in the number of perpetrators seen, especially under the violent condition. The accuracy of identificatio n was very low, with only 27% of the subjects making a correct identification; chance performance was observed with five perpetrators. Whereas a positive accuracy-confidence relationship held for identification under the nonviolent condition, this was not the case under the violent condition. These findings were related to court cases in which violence was interpreted as rendering eyewitness memory more reliable than in nonviolent situations.