This post was co-authored by Mattia Wruble, Williams College class of 2014.

A criminal case—and on the fate of the accused—often hinges on eyewitness testimony. A new article shows that eyewitnesses can be unreliable in a surprising way. They are good at describing the perpetrator of a crime. Case closed? Not quite. Describing involves recall, but identifying someone in a lineup requires recognition, and even eyewitnesses who are good at recall can fail at recognition.

Houston, Clifford, Phillips, and Memon (2013) did two studies at the University of Aberdeen. Participants were divided into two groups

  • The crime group watched a video in which a man stole an elderly woman’s handbag
  • The neutral group watched a video in which the same man and woman had a conversation during which the woman dropped her bag and the man picked it up for her

Twenty minutes later, participants were asked to recall every detail that they could about the video. The groups recalled different information: people who witnessed a crime were better able to describe the man in the video, but the neutral group was remembered what the man did better. The researchers suggest that when people realize they are witnessing a crime they intentionally focus on the perpetrator’s appearance so they can identify him/her later.

This sounds like good news. But in the second study, after watching the same videos, participants were asked to recognize the perpetrator in a photographic lineup of six similar looking people. This time the crime emotion group performed worse than the neutral group.

In other words, people who were better at describing a criminal were worse at recognizing him in a lineup. This dissociation between between recognition and recall is unintuitive—it seems like the more you know, the more you know—but it fits with previous research on memory. We store and retrieves different information when recalling than we do when recognizing (e.g., Meissner, Sporer, & Schooler, 2007)

Two lessons can be drawn from Houston et al.’s (2013) findings. First, jurors and judges tend to believe eyewitness, but even a witness who can recall vivid details of a crime might pick the wrong person out of a lineup. Second, memory does not always conform to intuition. When the stakes are high, which they are in any criminal court, intuition is no substitute for psychological evidence.

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Houston, Kate A., Clifford, Brian R., Phillips, Louise H., & Memon, Amina. (2013). The emotional eyewitness: The effects of emotion on specific aspects of eyewitness recall and recognition performance. Emotion, 13(1), 118-128. doi: 10.1037/a0029220

Meissner, Christian A., Sporer, Siegfried L., & Schooler, Jonathan W. (2007). Person descriptions as eyewitness evidence. In R. C. L. Lindsay, D. F. Ross, J. D. Read & M. P. Toglia (Eds.), The handbook of eyewitness psychology, Vol II: Memory for people. (pp. 3-34). Mahwah, NJ US: Lawrence Erlbaum Associates Publishers.

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