Economic inequality fosters unethical behaviour by promoting the perception of immoral and competitive normative climates.

Economic inequality was found to be positively related to unethical behaviours, but the underlying psychological mechanisms have not been well studied. Through five studies, this research explored the psychological mechanisms and boundary conditions between economic inequality and unethical behaviour. Study 1 (N = 165,622) provided primary evidence for the relationship between inequality and unethical behaviour based on large-scale publicly available databases. Using well-established questionnaires, Study 2 (N = 394) indicated that economic inequality positively predicted immoral and competitive normative climates, which positively predicted unethical behaviour. Study 3 (N = 160) and Study 4 (N = 188) provided causal evidence for the effect of economic inequality and repeatedly verified the mediating roles of immoral and competitive normative climates. Study 5 (N = 300) indicated that income level moderated the effect of economic inequality on unethical behaviour by moderating the mediating effect of immoral and competitive normative climates. In societies with high inequality, participants in low-income groups perceived stronger immoral and competitive normative climates, thereby engaging in more unethical behaviours. This research offers explanations for the prevalence of unethical behaviours in unequal societies, contributing to extend the emerging literature in social-ecological psychology that explores how macro-social-ecological factors impact micro-behaviours.