Order and Strength Matter for Evaluation of Alibi and Eyewitness Evidence

Abstract

We explored the effects of presentation order and evidence strength on participants acting as investigators in a criminal context. Participants evaluated evidence and suspect guilt in a study in which alibi witness and eyewitness evidence of varying strength, presented in different orders, were compared. In contrast to research on the confirmation bias, which suggests that evidence presented early distorts subsequent evaluations of evidence, the present findings suggest that under certain circumstances, evidence received most recently can have a greater impact on decision-making. Recency effects were observed most frequently when recent evidence was particularly strong and often when it contradicted previously encountered strong evidence. The impact of recency extended beyond the impact of evidence and to evaluations of the credibility of individual pieces of evidence. Copyright

Evidence Evaluation and Evidence Integration in Legal Decision‐Making: Order of Evidence Presentation as a Moderator of Context Effects

“…Note, however, that in both Dahl et al () and Price and Dahl (), their observed recency effects on evidence integration, like their observed recency effect on evidence evaluation, were only observed when the different pieces of evidence were of strongly opposite valences. Again, the current study includes one piece of evidence that is either incriminating or exonerating and an ambiguous piece of evidence that is not clearly incriminating or exonerating.…”

“…However, two recent studies did in fact manipulate the order in which evidence was presented and thus deserve mention. Dahl, Brimacombe, and Lindsay () and Price and Dahl () both presented participant–evaluators with two pieces of evidence (e.g., an alibi and an eyewitness identification decision) in one of two randomly assigned orders and then obtained a number of judgments, including the perceived credibility of the evidence (a measure of evidence evaluation). Results of both studies suggested that when two pieces of sequentially presented evidence have strong, opposite valences, the last piece of evidence is perceived as more credible than it would have been in the absence of the other evidence.…”

“…Second, both Dahl et al () and Price and Dahl () only used evidence of clearly opposite valences (one piece incriminating, the other exonerating). It is unclear whether a similar order effect would be found when one of the pieces of evidence is more ambiguous, not clearly pointing towards innocence or guilt.…”

“…However, there are data to suggest that order could matter. In both the Dahl et al () and the Price and Dahl () studies that manipulated order of evidence presentation, participants assessed the likelihood of the suspect's guilt (a measure of evidence integration). Both studies found that at least under some conditions, the last piece of evidence presented had a greater effect on the ultimate assessment of the suspect's guilt.…”

“…Price and Dahl () provided two theoretical mechanisms by which this recency effect might occur. First, they proposed that it may be a result of a contrast effect (Scherer & Lambert, ): When the last piece of evidence is of a different valence from the first piece of evidence, it may appear even stronger as a result of contrasting with the first piece.…”