Alibi believability: Corroborative evidence and contextual factors

A disbelief in alibis is one contributor to wrongful convictions. One reason that triers-of-fact may disbelieve alibis is that they lack evidence to corroborate the whereabouts of the suspect at the time of the crime. Contextual factors, such as when the alibi was disclosed and what was the nature of the crime, can also affect alibi believability. This paper outlines two studies where mock jurors evaluated an investigation and trial description online and rated alibi believability, defendant character trait ratings, and verdicts. Both studies examined the impact of corroborative alibi evidence and the timing of the alibi disclosure. In addition, Study 1 included the type of crime and Study 2 included the number of alibi corroborators as additional independent variables. We hypothesized that alibis would be viewed more positively when they were disclosed earlier rather than later, were corroborated by strong physical evidence and multiple corroborators, and involved less violent offenses. As hypothesized, in both studies, alibis with strong physical evidence were thought to be more believable than those with no physical evidence but the number of corroborators and type of crime did not affect any dependent measures. Delayed timing had some negative effects on views of the defendant's character. Corroborative physical evidence affected alibi believability consistently, and contextual factors mattered less. Both implications and suggestions for future research are further discussed.