The Effects of Witness Bias on the Identification of Perpetrators within a Photo Lineup


  • Maanasa Ravipati Undergraduate Student


Throughout the history of forensic science, the questioning of the reliability of eyewitness testimony and suspect identification has been prevalent. The purpose of this experiment is to determine the extent to which race affects the results of identifying a suspect in a photo lineup. This experiment particularly aims to determine how cross-race-effect impacts the accuracy of eyewitness identification. This study was carried out by setting up a mock crime with various mock witnesses and suspects. The witnesses were shown a picture of two perpetrators escaping the crime for approximately 20-30 seconds. The mock witnesses were instructed to note down any key characteristics to identify these suspects. After several weeks, the witnesses were sent out an online survey in which they are presented with two photo-lineups. One photo-lineup consisted of suspects from the same ethnic background as the majority of the witnesses and one photo lineup of suspects from a different background from the witness. It should be noted that some witnesses were not of the same ethnic background as either perpetrator. These photo lineups also consisted of cumulative descriptions of what the mock witnesses provided earlier in the experiment. The witnesses were then asked to identify the correct perpetrator from the lineup using this information. It was found that the majority of the mock witnesses accurately identified the perpetrators. However, the witnesses tend to identify the incorrect suspect when the suspect was of a different ethnic background than the witness. This finding is interesting as it implies that race impacts the reliability of eyewitness testimony.