Is The Bluff Enough? Examining the Effect of Different Variants of False Evidence on False Confessions

At present, the majority of false confessions are the result of psychologically manipulative interrogation tactics. Interrogators may use the false evidence ploy or the bluff ploy to elicit confessions. Unfortunately, research suggests that these interrogation tactics increase the risk of false confessions. At this time, research on the differential impact of the false evidence ploy and the bluff ploy is inconclusive, and there is little known about whether certain variants of false evidence are differentially powerful in eliciting false confessions. The present study examined the following: 1) the differential effect of the false evidence ploy and the bluff ploy on false confessions, and 2) the differential effect of three variants of false evidence on false confessions. The present study used a 2 (ploy: false evidence vs. bluff) by 3 (evidence variant: photograph vs. physical vs. eyewitness) between-subjects design. Participants (N=218) completed a logical reasoning task on a computer and were accused of violating the experimental protocol by pressing the space bar and seeing the answer. Participants were either shown faked (false) evidence, or told this evidence could be examined at a later date (bluff), and were then prompted to sign a confession statement. Results demonstrated that participants in the photograph evidence condition were more likely to falsely confess and to internalize guilt than participants in the physical evidence condition and eyewitness testimony condition. Results also demonstrated that participants in the false evidence condition were more likely to falsely confess and internalize guilt than participants in the bluff condition. The policy implications of these findings are discussed.