Brewer, N., Caon, A., Todd, C., & Weber, N. (2006). Eyewitness identification accuracy and
response latency. Law and Human Behavior, 30, 31 – 50.
The purpose of the present experiment was to further explore the effects of response latency on eyewitness identifications. Prior research (Dunning & Peretta, 2002) has shown that there is an optimum time interval for making accurate eyewitness identifications: that is, 10-12 sec. Dunning & Peretta argued that this time interval would be consistent regardless of the type or size of lineup used because accurate eyewitness identifications are made automatically. Because the decision is automatic, the person should “jump out” and this should take 10-12 sec.
Because of research conducted by Weber et al. (2004), which showed that the 10-12 sec. rule did not hold up across different experiments, Brewer et al. wanted to conduct different types of lineups in an effort to explore the time boundary.
Experiment 1
The purpose of experiment 1 was to determine if retention interval affected the optimum time boundary. Basic memory theories suggest that with increases in retention interval, recognition will take longer. Therefore, Experiment 1 had three retention intervals 0 min., 15 min., and 30 min. and two types of lineups (target-present and target-absent). Participants viewed a video of a shoplifter, then participated in the identification either 0, 15, or 30 minutes after the video.
Results
Consistent with Dunning & Stern, accurate identifications were made more quickly than inaccurate identifications. However, inconsistent with the predictions of Dunning & Stern, for choosers, the optimum time boundary increased as retention interval increased.
Experiment 2
The purpose of experiment 2 was to determine if the size of the lineup affected the optimum time boundary. The shoplifting video and a car theft video were presented to participants. Participants viewed a target present or a target absent lineup that had 4, 8, or 12 pictures.
Results
Accurate identifications were once again made more quickly than inaccurate ones. For the car theft video, there was a clear impact of lineup size on the optimum time boundary. As lineup size increased, the optimum time boundary increased. The data for the shoplifting video are less clear.
The results of the two experiments show instability in Dunning & Peretta’s 10-12 sec rule. The authors conclude that the variables of retention interval and lineup size both affected the optimum time boundary. The authors claim that this could be due to the proportion of automatic decisions, and if there had been more automatic decisions, the results would be more consistent with Dunning & Peretta. Therefore, they suggest that if there were some sort of distinguishing characteristic of the suspect, then automatic decisions would be more likely, thus making the optimum time boundary smaller. However, if there were no distinguishing characteristics, then automatic decisions would not be likely to be made, and the 10-12 sec rule should not be used to diagnose accuracy.
Important Legal Disclaimer: The preceding are articles we read together in the Lampinen Lab Fall 2006 false memory reading group. By clicking on the authors’ names of each article you can see the summary of that article. The summary was prepared by the student presenting that article and it is of course the case that the views expressed in the summary do not necessarily represent the views of the reading group as a whole, Dr. Lampinen, the Lampinen Lab, the University of Arkansas, the Razorback Football or Basketball teams (although we're not sure about cross country), people living down the street from us, Bob Dylan, Jack Fate, our extended families, or anyone else for that matter except for the student who wrote the summary (and they don't necessarily believe what they wrote either).