Motivated Cognition and Juror Interpretation of Scientific Evidence: Applying
Cultural Cognition to Interpretation of Forensic Testimony

Abstract

This paper reports the results of a study investigating how jurors interpret and digest scientific evidence when it is presented to them in a trial setting and how differences in juror attitudes and education influence interpretation of scientific evidence. The study involved a sample of mock jurors recruited from Amazon Mechanical Turk (n=91). Study subjects each viewed a transcript of a mock legal case involving DNA evidence. Results suggest that when presented with conflicting expert testimony, jurors will interpret evidence in a way that is consistent with pre-existing attitudes or beliefs (such as political predispositions). Importantly, results suggest that a juror’s ability to do this and therefore the polarization between jurors of different political pre-dispositions increases as level of education increases. For jurors classified as Conservative, as education levels increased, the prosecution expert was rated as more credible and the defendant was found guilty more often. For jurors classified as Liberal, as education levels increased, the prosecution expert was rated as less credible and the defendant was found guilty less often. Theoretical and practical implications of these findings are discussed.