A customer becomes the witness of a bank robbery. While still at the bank, he provides the police with a description of the perpetrator: male, dark hair, slim, black sweater. That’s all he can recall. One week later the witness is invited to a personal interview with a police officer. Here he suddenly states that the perpetrator wore jeans. Should the police regard this new piece of information as credible?
We are just too familiar with the fact that we increasingly forget information as time passes. The opposite case, that is, remembering information at a later time that had first seemingly been forgotten, is less intuitive. Wouldn’t it be more plausible that the witness in our example picked up the new information “jeans” in a news report or during a discussion with a co-witness? In any case, this new information should be treated with skepticism.
But things aren’t as simple as that. Reminiscence, remembering information that has not been recalled previously, is “normal”. Almost anyone experiences it. Reminiscence occurs, because not all details are equally accessible in memory at a given point in time. The more disparate two retrieval attempts are, the more likely reminiscence will occur. Such differences can arise, for instance, when interview styles differ or different kinds of questions are asked.
Not only laypersons, but also experienced police detectives can be unaware of this. In a recently published study, police detectives were asked to estimate the recall performance of a group of participants who had been interviewed twice about a staged theft at intervals of one week. They assumed that the accuracy of reminiscent information would be as low as 29%. They also voiced the concern that these details were likely to be misinformation (e.g., from news reports). The discrepancy between the detectives’ estimates and actual eyewitness performance was remarkable: In fact, the accuracy of reminiscent information was 86%. The detectives’ mistrust in reminiscence is problematic. It can make the police disregard important leads, which can ultimately jeopardize the success of the investigation.
What should be done with reminiscent information? The police should inquire with the witness whether there are any indications that this new detail is the result of media or co-witness influence. If this is not the case, chances are high that the new detail is correct.
Krix, A. C., Sauerland, M., Lorei, C., & Rispens, I. (2015). Consistency across repeated eyewitness interviews: Contrasting police detectives’ beliefs with actual eyewitness performance. PLoS ONE, 10, e0118641. doi:10.1371/journal.pone.0118641
Oeberst, A. (2012). If anything else comes to mind . . . better keep it to yourself? Delayed recall is discrediting: Unjustifiably. Law and Human Behavior, 36, 266-274. doi:10.1037/h0093966
Written by Alana C. Krix and Melanie Sauerland, this blog was originally published in German at de.in-mind.org (http://de.in-mind.org/blog/post/inkonsistenter-zeuge-unglaubwuerdiger-zeuge-wenn-zeug-innen-ihre-aussage-spaeter-ergaenzen).