Sex differences in the psychophysiological response to an intergroup conflict

•Intergroup conflict induced more conflict perception and negative mood.•During conflict, participants showed decreases in parasympathetic activation.•During conflict, only women showed decreases in testosterone levels.•Conflict perception only correlated with psychophysiological responses in women.•Results suggest that men and women interpret intergroup conflict differently. Conflict induces psychophysiological responses, but less is known about responses to intergroup conflict. Intergroup relationships activate social processes, adding complexity to people’s physiological responses. This study analyzes the psychophysiological responses to intergroup conflict considering sex differences. Thus, 150 young people were distributed in 50 groups in two conditions (conflict vs. non-conflict). Conflict was created in the interaction between two groups (three people each) in the laboratory. Their responses were compared to a control group. Mood, heart rate variability, cortisol, and testosterone were measured. Results showed that intergroup conflict induced a less pronounced decrease in negative and positive mood, and a reduction in parasympathetic activity (RMSSD of IBI). Moreover, women in conflict showed lower testosterone levels than men in conflict and control women. Finally, women’s conflict perception correlated with their psychophysiological response. Results suggest that intergroup conflict induces emotional, cardiovascular, and endocrine responses, and that men and women interpret conflict differently.