The influence of hypothesis disconfirmation on attribution error in juror perceptions of confession evidence

Jurors are vulnerable to an array of cognitive biases that can result in an over-belief of confession evidence. A combination of automatic acceptance, self-serving expectations and the Fundamental Attribution Error may result in an initial hypothesis of guilt, with confirmation bias reinforcing this with the evaluation of subsequent evidence. There were two main aims of this research. First, to examine the extent to which mock jurors are sensitive to inconsistencies in confessions. Second, to test the capacity of a hypothesis disconfirmation intervention to enhance sensitivity to inconsistencies by encouraging mock jurors to more critically evaluate confession evidence. The online study followed a 2 (confession strength: weak, strong) x 3 (hypothesis disconfirmation: pre-confession, post-confession, control) between-subjects design. Participants read a police report detailing the facts of a crime and a signed confession statement (either weak and inconsistent with the police report, or strong and consistent). Participants in hypothesis disconfirmation conditions listed up to 10 reasons why someone might falsely confess. Confession strength had a significant main effect on perceived consistency of confession evidence (p<.001), verdict (p=.004) and verdict preference (p=.006), while perceived likelihood of guilt bordered on significance (p=.053). Neither the hypothesis disconfirmation nor the strength x hypothesis disconfirmation interaction had any significant main effects on any of the dependent variables (p>.05). It seems, mock jurors were sufficiently sensitive to inconsistencies in the confession evidence, leaving little room for the hypothesis disconfirmation to have any effect. Before hypothesis disconfirmation is labelled as an ineffective technique for encouraging jurors to more critically evaluate confession evidence, its efficacy should first be tested in cases where jurors' over-belief in confession evidence is more pronounced.