Do resources make adolescents happier? Belief in a just world as an adaptive mediator between subjective socioeconomic status and life satisfaction

Life satisfaction is adaptive, yet the antecedents of its adaptability require further exploration. Drawing from evolutionary psychology, this study aimed to investigate the adaptive mechanisms underlying happiness among adolescents, considering that adaptation involves subjective evaluation, including both first-order and second-order evaluations. Through a cross-sectional study (Study 1) and a longitudinal study (Study 2), this research examined the impact of subjective socioeconomic status on life satisfaction and the mediating roles of general and personal belief in a just world. Findings from both studies indicated that subjective socioeconomic status positively predicts life satisfaction. Moreover, it was the general belief in a just world, rather than the personal belief in a just world, that mediated this relationship. This study examined how evolutionary theory and second-order evaluation theory explain the impact of subjective socioeconomic status on life satisfaction, emphasizing the belief in a just world as a crucial adaptive belief mediating this relationship. We should emphasize the belief in a just world among adolescents with low subjective socioeconomic status, as a strategy to boost their long-term happiness. By fostering a sense of fairness and acceptance in adolescents' evaluations of their socioeconomic status, we can better promote their mental health and overall happiness.