Cognitive bias research in forensic science: A systematic review

The extent to which cognitive biases may influence decision-making in forensic science is an important question with implications for training and practice. We conducted a systematic review of the literature on cognitive biases in forensic science disciplines. The initial literature search including electronic searching of three databases (two social science, one science) and manual review of reference lists in identified articles. An initial screening of title and abstract by two independent reviewers followed by full text review resulted in the identification of 29 primary source (research) studies. A critical methodological deficiency, serious enough to make the study too problematic to provide useful evidence, was identified in two of the studies. Most (n = 22) conducted analyses limited to practitioners (n = 17), forensic science trainees (n = 2), or both forensic science practitioners and students (n = 3); other analyses were based on university student or general population participants. Latent fingerprint analysis was examined in 11 studies, with 1-3 other studies found in 13 other disciplines or domains. This set of studies provides a robust database, with evidence of the influence of confirmation bias on analysts conclusions, specifically among the studies with practitioners or trainees presented with case-specific information about the "suspect" or crime scenario (in 9 of 11 studies examining this question), procedures regarding use of exemplar(s) (in 4 of 4 studies), or knowledge of a previous decision (in 4 of 4 studies). The available research supports the idea of susceptibility of forensic science practitioners to various types of confirmation bias and of the potential value of procedures designed to reduce access to unnecessary information and control the order of providing relevant information, use of multiple comparison samples rather than a single suspect exemplar, and replication of results by analysts blinded to previous results.