Camera footage and identification evidence undermine the availability of exculpatory alibi evidence

The present field experiment investigated how alibi witnesses react when confronted with camera or identification evidence that incriminates an innocent suspect. Under the pretext of a problem-solving study, pairs of participants (N = 109) and confederates worked on an individual task with a dividing wall obstructing their view of each other. When the mobile phone of the experimenter was missing from an adjacent room at the end of the session, all participants confirmed that the confederate had not left the room. After several days, participants returned to the lab for a second session. They were asked to confirm their corroboration, orally and in writing, after learning that the confederate either had been identified from a photograph or was present on camera footage. A control group received no evidence. In this second session, written (but not oral) alibi corroboration was weaker in the incriminating evidence conditions (47%) than the no-evidence condition (81%), as hypothesized. Unexpectedly, corroboration was equally strong in the camera and identification evidence conditions. The current findings provide first evidence that camera surveillance and eyewitness identification evidence can bear on the availability of exculpatory alibi evidence in court and emphasize the need for documenting incidents of evidence contamination.