Boiling Points: Evaluating State and Trait Predictors of Heat-induced Reactive Aggression

Ambient temperature has been robustly linked to aggressive behavior, a relationship that is expected to intensify as climate change increases exposure to heat. Despite the consistency of this association at the macro level, laboratory studies testing psychological mechanisms often yield mixed or null effects. The present study tested a novel cognitive mechanism of the heat–aggression link while examining whether individual differences moderate responses to heat. Across two laboratory sessions, 79 participants completed a moderate heat stress condition and a thermoneutral control condition. In each session, participants reported affect and thermal comfort, responded to frustrating hypothetical scenarios, completed measures of working memory and inhibitory control, and performed a behavioral task assessing impulsive, reactive aggression. Heat reliably reduced comfort and positive affect and increased anger responses to frustrating scenarios. However, heat did not produce main effects on negative affect, cognitive performance, or reactive aggression, nor did affective or cognitive measures mediate any effect of heat on aggression. In contrast, moderation analyses revealed that temperature interacted with trait impulsivity—specifically the tendency to act without forethought—such that individuals higher in impulsivity exhibited greater impulsive, reactive aggression under heat stress. These findings suggest that heat may not uniformly increase aggression, but instead amplifies preexisting dispositional tendencies. This interactionist account helps reconcile mixed findings in prior experimental research and highlights the importance of considering individual differences when examining situational effects of environmental stressors on social behavior.