Evaluating hypothesis-inconsistent evidence: The effects of background knowledge, order, and strength of arguments

Coherence-based models of reasoning suggest that the ways in which individuals incorporate information into a decision representation varies dependent upon whether it is hypothesis-consistent or hypothesis-inconsistent. This is particularly relevant in a legal context as in order to produce a judgment or decision, legal decision makers must decide which pieces of information are relevant to their preferred explanation of the case and what information will be filtered out. Background knowledge, order of information presentation, and strength of arguments have been highlighted as important to decision making. However, these elements have not yet been explored together to determine whether there are any interaction effects upon decisions made in the face of hypothesis-inconsistent information. Through the use of fictional murder and robbery scenarios, two experiments were conducted in order to determine the effects of incriminating and non-incriminating evidence on decision making in conditions of varying suspect-related background information and order of evidence presentation. Additionally, each experiment looked at different strengths of hypothesis-inconsistent arguments. In both experiments, the relationship between decision making and order of non-incriminating evidence presentation was different dependent upon background information, however, this relationship also varied between the murder and robbery scenarios. These experiments have added to the literature which suggest that the preconceptions of investigators can bias their evaluation and perception of subsequent information, and that order of evidence presentation impacts subsequent judgments of guilt. Additional research is required to determine whether these findings may generalise to more complex investigative representations.