Doctor of Philosophy (PhD)



Document Type



Two experiments were conducted to investigate the effects of gruesome evidence on mock jurors? decisions in a simulated capital trial. The first experiment was designed as a replication and extension of Douglas, Lyon, and Ogloff (1997), who found that mock jurors who were presented with gruesome photographic evidence were nearly twice as likely to convict the defendant than participants who did not see the gruesome evidence. In Experiment 1, gruesome evidence was manipulated in two ways: photographic evidence (low gruesome, highly gruesome, or control photographs) and verbal testimony (low gruesome vs. highly gruesome). Neither photographic evidence nor testimony had an effect on mock jurors verdicts or sentence decisions. However, the manipulation check failed to indicate that participants perceived the evidence differently in terms of gruesomeness. Experiment 2 was designed to address whether inducing specific emotions in participants would produce similar biasing effects on their decisions as gruesome evidence. Previous research has eluded to emotional arousal as a potential mediator of the effects of gruesome evidence. Participants were induced to feel either angry or sad and were compared to participants who were given a neutral-emotion induction and viewed either low or highly gruesome photographs. The results indicated that neither emotion nor gruesome photographic evidence had an effect on participants? verdicts. However, participants? who viewed highly gruesome photographic evidence were more likely to decide on the death sentence than participants who viewed the low gruesome evidence. The results are discussed in light of the previous research on gruesome evidence and theories of emotion and decision making.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Janet McDonald



Included in

Psychology Commons