Neural evidence for narrative-based processing of evidence and bias in juror decision making

Abstract Efforts to explain complex human decisions have focused on competing models emphasizing utility, narrative, and social-affective mechanisms. These are difficult to distinguish using behavior alone. Jury decisions are among the most consequential complex decisions made in a modern society, and both narrative and utility models have been proposed to explain juror decisions. Here, we use patterns of brain activation derived from large neuroimaging databases to look for signatures of the cognitive processes associated with models of juror decision making. We asked jury-eligible subjects to rate the strength of a series of criminal cases while recording the resulting patterns of brain activation. When subjects considered evidence, cognitive processes associated with narrative models better explained the patterns of brain activation than cognitive processes associated with utility. In contrast, a biasing effect of crime type on perceived strength of the case was best explained by brain patterns associated with social cognition. Our results support a central role for narrative in integrating evidence and biases in complex decisions.