The Impact of Viewing Social Media Images on Eyewitness Identification

After observing a crime, eyewitnesses may conduct their own investigation on social media to search for the perpetrator. In two experiments, participants viewed an image of an innocent suspect in the time between viewing a mock-crime video and completing a lineup procedure. The image was presented in the context of a social media search or a police mugbook viewing. A control group viewed no photos of innocent people before the lineup. The same images were used in the mugbook and social media conditions, but the social media profiles were designed so that the innocent suspect stood out as the only person who had mutual friends with the participant. In both experiments, the innocent suspect was more likely to be mistakenly identified if they were previously viewed on social media relative to the control condition. The mugshot viewing also increased innocent suspect identifications, but only after the plausibility of the innocent suspect was increased in Experiment 2. Relative to the control condition, participants who viewed either a mugbook or social media had lower accuracy when they identified the suspect with high confidence. These findings indicate that viewing images of innocent people can contaminate the memory of eyewitnesses, influence identifications at a subsequent lineup procedure, and undermine the eyewitness confidence-accuracy relation.