LE3 .A278 2005

2005

Potter, Susan

Acadia University

Bachelor of Science

Honours

Psychology

Psychology

An investigation of the Familiarity Effect and the Optimality Hypothesis was conducted by examining the impact of the presence of a bystander during a mock crime on eyewitness accuracy and confidence when later attempting to identify the perpetrator from a mugshot line-up. Similar investigations have been carried out by West & Potter (2002) and West (2003) using a mock crime on video, in which participants were forewarned of the crime and immediately asked to identify the perpetrator from a line-up. The current study used a live mock crime in which participants were not forewarned and were asked to return two days later to identify the perpetrator. Ninety participants (22 males and 68 females) viewed one of four sequential mugshot line-ups containing both frontal and ¾ view mugshots of six males as follows: 1) perpetrator only (PO), 2) bystander only (BO), 3) both perpetrator and bystander (PB), and 4) neither perpetrator nor bystander (NPB). Participants also answered questions concerning how decisions were made once the viewing of the mugshot line-up was completed. Accuracy and confidence levels were measured along with the number of bystander-identifications and non-identifications made. The results indicate that participants who made a correct decision were less confident than those who made an incorrect decision. It was also found that accuracy was lowest in the NPB condition and highest in the PB condition. Possible explanations of these findings are discussed as well as future directions for studying eyewitness identification.

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https://scholar.acadiau.ca/islandora/object/theses:446