Are Two Interviews Better Than One? Eyewitness Memory across Repeated Cognitive Interviews

Eyewitnesses to a filmed event were interviewed twice using a Cognitive Interview to examine the effects of variations in delay between the repeated interviews (immediately & 48 hours; immediately & 7 days; 7 & 9 days) and the identity of the interviewers (same or different across the two repeated interviews). Hypermnesia (an increase in total amount of information recalled in the repeated interview) occurred without any decrease in the overall accuracy. Reminiscence (the recall of new information in the repeated interview) was also found in all conditions but was least apparent in the longest delay condition. The number of errors, increased across the interviews, but the relative accuracy of participants’ responses was unaffected. However, when accuracy was calculated based on all unique details provided across both interviews and compared to the accuracy of recall in the first interview it was found to be slightly lower. The identity of the interviewer (whether the same or different across interviews) had no effects on the correct details. Given the increase in the amount of new information reported in the repeated interview, with little cost to the overall accuracy of information gathered, it is concluded that there may be considerable value in providing witnesses with a second opportunity to recall information about events in question. Importantly, these results suggest witnesses are unlikely to report everything they remember during a single Cognitive Interview, however exhaustive.