When a silhouette appears male: Observer’s own physical fitness governs social categorization of sexually ambiguous stimuli

Abstract

Categorization bias in social cognition is widely observed, as it is more beneficial to commit low-risk biases in order to reduce high-risk biases. Here, we hypothesized that a low capacity of self-protection leads to a biased social categorization of others as “harmful”. To examine this, silhouettes of human body, which had a sexually dimorphic cue (waist-to-hip ratio), were presented, and participants categorized the stimuli as being either “female” or “male”. Participants’ basic physical fitness was measured, and we manipulated exogenous physical load by either a heavy or a light backpack. Physical load did not significantly influence sex categorization. In contrast, only female participants tended to categorize the stimuli as “male” more, as basic physical fitness increased, suggesting that basic physical fitness, not physical load, affects sex categorization for females. Our findings shed new light on the role of fitness factors in social cognition.