Longitudinal relations between personal belief in a just world and adolescent aggressiveness.

Scholars have emphasized the need for longitudinal research to investigate the reciprocal influence of personal belief in a just world (PBJW) and aggressiveness, yet such investigations remain limited. The current study aimed to examine the bidirectional associations between PBJW and four distinct facets of aggressiveness (hostility, anger, physical aggression, and verbal aggression), and to explore the moderating roles of gender and age group. We conducted a longitudinal survey with 1423 Chinese middle-school students (54.4% girls; Mage = 13.50, SDage = 1.46 at Time 1) at two time points over a six-month interval. To determine the directional ordering of these constructs, we employed a cross-lagged panel model, which estimates the unique predictive effect of one variable on another over time while controlling for the autoregressive stability of each variable. The results showed that initial PBJW predicted subsequent decreases in anger, physical aggression, and verbal aggression, but did not predict hostility. Conversely, initial hostility predicted a later decline in PBJW, whereas anger, physical aggression, and verbal aggression did not predict subsequent PBJW. These associations were invariant across gender and age groups. These findings underscore the protective function of PBJW against the affective and behavioral aspects of aggressiveness while highlighting that hostility can erode adolescent PBJW.