Disgust and biological descriptions bias logical reasoning during legal decision-making

Abstract

Legal decisions often require logical reasoning about the mental states of people who perform gruesome behaviors. We use functional magnetic resonance imaging (fMRI) to examine how brain regions implicated in logical reasoning are modulated by emotion and social cognition during legal decision-making. Participants read vignettes describing crimes that elicit strong or weak disgust matched on punishment severity using the US Federal Sentencing Guidelines. An extraneous sentence at the end of each vignette described the perpetrator’s personality using traits or biological language, mimicking the increased use of scientific evidence presented in courts. Behavioral results indicate that crimes weak in disgust receive significantly less punishment than the guidelines recommend. Neuroimaging results indicate that brain regions active during logical reasoning respond less to crimes weak in disgust and biological descriptions of personality, demonstrating the impact of emotion and social cognition on logical reasoning mechanisms necessary for legal decision-making.

Keywords:

• Disgust
• Legal decision-making
• Logical reasoning
• Dehumanization

View correction statement:

Corrigendum

We thank Dena Gromet and Walter Sinnott-Armstrong for their help with study design and feedback. These data were presented at the annual Social and Affective Neuroscience Society Meeting, April 2012.

This article was originally published with errors. This version has been corrected. Please see Corrigendum http://dx.doi.org/10.1080/17470919.2014.903083

Notes

¹  Given that the contrast used was valid + invalid > baseline (fixation), we found regions that were less active during the task, including the superior frontal gyrus, parahippocampal gyrus, and medial frontal gyrus. These regions have previously been implicated in default mode activity (see Buckner, Andrews‐Hanna, & Schacter, 2008), and were not included in our statistical analyses.