Cognitive bias in forensic pathology decisions

Abstract

Forensic pathologists' decisions are critical in police investigations and court proceedings as they determine whether an unnatural death of a young child was an accident or homicide. Does cognitive bias affect forensic pathologists' decision-making? To address this question, we examined all death certificates issued during a 10-year period in the State of Nevada in the United States for children under the age of six. We also conducted an experiment with 133 forensic pathologists in which we tested whether knowledge of irrelevant non-medical information that should have no bearing on forensic pathologists' decisions influenced their manner of death determinations. The dataset of death certificates indicated that forensic pathologists were more likely to rule "homicide" rather than "accident" for deaths of Black children relative to White children. This may arise because the base-rate expectation creates an a priori cognitive bias to rule that Black children died as a result of homicide, which then perpetuates itself. Corroborating this explanation, the experimental data with the 133 forensic pathologists exhibited biased decisions when given identical medical information but different irrelevant non-medical information about the race of the child and who was the caregiver who brought them to the hospital. These findings together demonstrate how extraneous information can result in cognitive bias in forensic pathology decision-making.

Keywords: bias; cognitive bias; confirmation bias; contextual influence; decision-making; expertise; forensic pathology; forensic science; stereotypes; task-relevance.

FIGURE 1

Eight sources of bias that may impact observations and conclusions, even by expert scientists. They are organized in a taxonomy with three categories: starting at the top, with sources relating to the specific case at hand (Category A); sources relating to the specific person conducting the analysis (Category B); and at the bottom, sources that relate to human nature (Category C). Taken from [7] [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 2

Forensic pathologists were more likely to attribute the deaths of Black children to homicide, relative to White children; whereas the deaths of White children, relative to black, were more likely deemed accidental [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 3

With identical medical findings, the proportion of forensic pathologists determining that the manner of death was an "accident" (left panel) vs. a "homicide" (right panel). White bars are for White children with the grandmother as a caretaker; Black bars are for Black children with the mother's boyfriend as a caretaker. When the forensic pathologists could not reach a decision (an "accident" or "homicide") with confidence, they concluded that the manner of death was "undetermined" [Color figure can be viewed at wileyonlinelibrary.com]