Cognitive Bias in Legal Decision-Making: New Evidence from Psychological Studies

Presenter: Yian Xu

Research Category:
Student Type: Graduate
PI: John Coley
Award: Scholarship
Award Winner Category: Social Sciences, Business and Law

The rational application of law is not the only factor that de facto informs legal decisions. Converging evidence indicates cognitive biases in legal decision-making, including confirmation bias, anchoring errors, representativeness bias and so on. However, no research has ever looked at how psychological essentialism–a cognitive framework that people intuitively endorse to reason about categories–influences legal decision-making.

The current project takes the initiative to combine well-established theories and methods in cognitive psychology with practical legal concerns in criminal justice. Particularly, the current project aims to investigate how essentialist beliefs, or the tendency to perceive crime categories as naturally defined, caused by an underlying essence, historically invariant and culturally universal, affects culpability judgment and punishment decisions.

Results from the current project have important implications for criminal justice. Our preliminary data shows that, as we predicted, essentialist belief plays an independent and statistically reliable role in affecting culpability judgment (β=.111, p=.014) and sentencing decisions (β=.131, p=.001), at least with US lay participants. Opposed to what people might expect, people are influenced by their prior essentialist beliefs about crime categories when making important legal decisions, which has not been documented ever before.

The current project aims to quantify the practical consequences of essentialist bias, and involves participants from understudied population as well as legal practitioners in order to thoroughly examine the effect, so as to set out the first step to seek prevention and remedy for criminal justice.