Self-protection motives bias legal decisions against physically formidable men

Women with heightened beliefs in a dangerous world recommended harsher minimum sentences for physically strong male defendants compared to weaker ones, according to a new study published in Evolutionary Psychological Science.

Throughout human history, the ability to detect and respond to potential threats has been critical for survival. One significant cue used to infer threat potential is men’s physical formidability, which is often linked with aggression.

While these threat detection heuristics have evolutionary advantages, they may lead to biases in modern contexts, such as legal decision-making. Legal systems aim to eliminate bias, but judgments rooted in ancestral survival mechanisms may interfere with this goal.

Researchers Bridget A. O’Neil and Mitch Brown sought to understand how women’s self-protection motives, shaped by beliefs about a dangerous world, influence their punitive decisions against physically strong men in a legal setting.

The study included 214 undergraduate students (108 men, 106 women) from a large public university in the southeastern United States. Participants, aged 18-23, completed tasks in a mock jury paradigm. They were presented with a vignette describing a male defendant convicted of first-degree aggravated assault. The scenario detailed an unprovoked attack outside a bar, during which the defendant physically assaulted the victim, leaving them hospitalized with severe injuries.

The mock jurors were tasked with recommending minimum and maximum sentences for the defendant based on the described case. Participants were randomly assigned to view one of two images of the defendant: one manipulated to depict a physically strong man and the other a physically weak man. The images were standardized, using the same facial features paired with either a strong or weak body, to ensure that only perceptions of physical formidability varied between conditions.

Participants evaluated the defendant’s perceived strength, aggression, and dangerousness on seven-point scales to confirm the manipulation of formidability. Additionally, participants completed the Belief in a Dangerous World (BDW) Scale, which measures individuals’ dispositional beliefs about the prevalence of danger and violence in the world.

The study’s manipulation checks revealed that participants reliably perceived the “strong” defendant as stronger, more aggressive, and more dangerous compared to the “weak” defendant, validating the experimental design.

Gender differences emerged in how self-protection motives influence sentencing decisions. Women’s BDW scores significantly predicted their leniency, or lack thereof, toward the physically strong defendant. Women with higher BDW scores, indicating heightened self-protection motives, were less likely to recommend the minimum sentence for the strong defendant compared to the weak one. In contrast, women with lower BDW scores showed greater leniency toward the strong defendant, possibly reflecting a focus on the benefits of strength, such as protection, in the absence of heightened threat sensitivity.

For men, BDW scores did not significantly influence sentencing recommendations, nor did they show differential treatment of strong versus weak defendants. This lack of effect suggests that men’s punitive decisions may be less shaped by self-protection motives or perceptions of formidability.

Interestingly, no significant differences were observed in the maximum sentence recommendations for either men or women, potentially indicating that participants were more influenced by minimum sentencing decisions.

Of note is that participants were primarily college-aged individuals, which may limit the generalizability of the findings to actual juries, typically composed of older adults. Additionally, the focus on a single crime type (i.e., aggravated assault) may not capture the full range of biases present in legal contexts involving other crimes.

Overall, this study demonstrates how evolutionary self-protection mechanisms can shape modern legal judgments, underscoring the challenge of balancing fairness in legal proceedings with deeply ingrained threat detection systems.

The research, “Women’s Dangerous World Beliefs Predict Biases Against Formidable Men in Legal Domains,” was authored by Bridget A. O’Neil and Mitch Brown.