Social cognitive processes explain bias in juror decisions

Abstract

Jury decisions are among the most consequential social decisions in which bias plays a notable role. While courts take a number of measures to reduce the influence of bias on decisions about case strength or deserved punishment based on evidence introduced during a trial, jurors may still incorporate personal biases based on knowledge, experience, emotion, and beliefs independent of evidence. One common form of this bias, crime-type bias, is the extent to which the perceived strength of a case depends on the severity of the crime. A number of explanations from psychology and law point to the role of moral judgment, social cognition, and affect as core processes of bias. However, behavioral evidence alone makes these explanations difficult to distinguish. To overcome this challenge, we used fMRI to record brain activation patterns of mock jurors as they read a series of criminal scenarios and rated the strength of the cases and deserved punishment. Compared to patterns of brain activation derived from large neuroimaging databases, mock jurors’ neural activation patterns related to crime-type bias were most similar to patterns associated with social cognition (such as those associated with mentalizing and racial bias) but not affect or moral judgment. Further, results indicated that crime-type bias could be explained by variability in victim harm. Our results support a central role for social cognition in juror decision making and suggest that crime-type bias may arise from similar mechanisms that precipitate other biases like stereotypes about culture or race.

Neural support for contributions of utility and narrative processing of evidence in juror decision making

“…Elsewhere, we found that brain activation patterns associated with scenario effects on case strength are distinct from the patterns described here for evidence accumulation (Castrellon et al, 2021). These scenario effects were associated with brain regions related to social cognition.…”

“…Since this model has the advantage of accounting for sparsely sampled data, we can estimate effects for all scenarios even though participants did not view all possible combinations of scenarios and evidence types. We previously applied this model to a large online sample of participants (Pearson et al, 2018) and show here that the model generally replicates case strength and punishment effects (Castrellon et al, 2021).…”

“…Here, we examine cognitive processes associated with evidence accumulation. We address the effects of different crime scenarios in a separate manuscript (Castrellon et al, 2021).…”

“…Crime type and evidence accumulation thus represent distinct influences on case strength. Activation patterns associated with crime-type bias are located in a region of cortex associated with social cognition, including cultural and ideation bias (Castrellon et al, 2021). This crime-type activation is distinct from, but neighboring, those described here for the accumulation of evidence.…”

“…This manuscript analyzes different models of evidence accumulation for a dataset previously reported in (Castrellon et al, 2021); the previous study examined models of evidence-independent bias in juror decision making. Thirty-three healthy jury-eligible adults between the ages of 18 and 52 were recruited from the Durham, NC community and underwent a single-session fMRI scan.…”