Where were you last night?: alibi believability and corroborating evidence : a new direction in psychology and law
Is Version Of
This thesis discusses the definition of alibi, including the nature of evidence needed to support an alibi, and introduces a proposed taxonomy of alibi strength based on perceived believability. The taxonomy is composed of 12 entries represented by a factorial combination of four levels of person evidence and three levels of physical supporting evidence. Participants (N = 252) evaluated three alibis, with physical evidence as within-subjects variable and person evidence as a between-subjects variable. Participants rated the alibis according to believability and the likelihood that the alibi provider was the culprit. They also rated the alibi providers on various trait descriptions. Alibis with stronger levels of physical or person corroboration were rated as more believable than alibis with no physical or person corroboration. Physical evidence moderated the effect of person evidence: As strength of physical evidence increased, the effect of person evidence diminished. Likelihood judgments and relevant trait ratings showed a similar pattern to believability judgments. Interestingly, trait ratings on irrelevant dimensions were also affected by alibi strength. Evaluators generally make distinctions among alibis along the lines of the proposed taxonomy, indicating high promise for the use of the taxonomy in future alibi research.