Judicial instructions on alibis: impact on mock jury decision-making

Cloud Research (N = 320) participants read a hypothetical description of an arson and police investigation. They were randomly assigned to one of eight conditions in a 2 (presence of alibi evidence) X 2 (presence of prosecution evidence) X 2 (presence of judicial alibi instructions) between-participants design. They completed alibi believability ratings, chose a verdict and evaluated the defendant's character. Alibis were more believable in the absence of incriminating prosecution evidence and the presence of exonerating alibi evidence. Alibi evidence also led to more positive views of the defendant. The presence of judicial instructions decreased likelihood of guilt ratings. Most participants chose a not guilty verdict, yet guilty verdicts were more common when prosecution evidence was present. Scalar verdict-confidence ratings were higher when prosecution evidence was present and alibi evidence was absent. While participant recall on the judge's instructions were poor, they performed well on two recognition questions.