Acute psychological stress promotes implicit aggression: Evidence from behavior and ERPs.

Acute stress affects explicit aggressive behavior through two distinct behavioral patterns: "fight or flight" and "tend and befriend". However, the impact of acute stress on implicit aggression remains less explored. We investigated the effect of acute stress on implicit aggression with event-related potentials (ERPs; N2, P2, P3, and N400) measures. A total of 55 healthy individuals were randomly allocated to either the Trier Social Stress Test (TSST) group (N = 31, 14 females) or a neutral control group (N = 24, 15 females). Following this, participants completed the Single Target-Implicit Association Test (ST-IAT) while electroencephalogram (EEG) data were collected. We found that acute stress strengthens the associations between self-related words and aggressive words relative to nonaggressive words. At the neural level, N2 and N400 components amplitudes were significantly smaller following the TSST relative to the control group. The compatible task in the ST-IAT elicited a larger P2 amplitude than that in the incompatible task. Our results support the model of "fight or flight" where humans choose to attack or escape to survive under stress.