ABSTRACT Objective The role of personality in the mechanism underlying the decrease in reactive aggression (RA) and proactive aggression (PA) at the within‐person level remains unclear. This study addresses this issue from the perspective of protective personality. Method Social responsibility, moral disengagement, RA, and PA were assessed in three waves (W1–W3) over 1 year in 1134 undergraduates. A random intercept cross‐lagged panel model (RI‐CLPM) was used. Results The random intercepts of the four research variables were associated with each other. At the within‐person level, social responsibility at W1 indirectly negatively predicted subsequent changes in RA at W3 through changes in moral disengagement at W2. A bidirectional negative relationship was found between social responsibility and moral disengagement at the within‐person level over time. Conclusions At the within‐person level, changes in RA were due to the serial effect of social responsibility and moral disengagement, suggesting that prosocial personalities may inhibit aggression by suppressing negative moral cognition (moral disengagement). Social responsibility and moral disengagement may form a cascading loop, which promotes the development of prosocial personalities, and in turn, inhibits the development of aggression. These findings facilitate the understanding of the mechanism underlying the decrease in RA from a protective personality perspective.
Lin et al. (2026) studied this question.