Cognitive Biases in Criminal Case Evaluation: A Review of the Research

Psychological heuristics are an adaptive part of human cognition, helping us operate efficiently in a world full of complex stimuli. However, these mental shortcuts also have the potential to undermine the search for truth in a criminal investigation. We reviewed 30 social science research papers on cognitive biases in criminal case evaluations (i.e., integrating and drawing conclusions based on the totality of the evidence in a criminal case), 18 of which were based on police participants or an examination of police documents. Only two of these police participant studies were done in the USA, with the remainder conducted in various European countries. The studies provide supporting evidence that lay people and law enforcement professionals alike are vulnerable to confirmation bias, and there are other environmental, individual, and case-specific factors that may exacerbate this risk. Six studies described or evaluated the efficacy of intervention strategies, with varying evidence of success. Further research, particularly in the USA, is needed to evaluate different approaches to protect criminal investigations from cognitive biases.