The association between social class and aggression: A meta-analytic review

Substantial evidence links social class with aggression. Despite lower social class being recognized as a risk factor for high levels of aggression, the findings of this association have been inconsistent. Some studies have indeed illustrated that a social class level is inversely associated with aggression, while other studies have demonstrated positive or null associations. To clarify previously inconsistent findings, this meta-analysis assesses the overall magnitude of this relationship and examines the potential moderators. A total of 268 studies met the inclusion criteria, and we used 546 effect sizes in 357 independent samples from these studies. A random-effects meta-analytic model was employed and several moderator analyses were conducted. Overall, social class shared a small but significant negative relationship with aggression (r = −0.092). Moderator analyses suggested that study-level (e.g., type of study, and national differences), sample-level (e.g., age), class-level (e.g., type, assessment, and source of social class), and aggression-level (e.g., type of aggression) characteristics accounted for heterogeneity in the relationship. Additional analyses also revealed the robustness of these effects with little evidence of publication bias. Living in disadvantaged socioecological environments, lower-class individuals may exhibit more aggression to adapt to threats. Moreover, the relationship between social class and aggression is not fixed and can change with specific contexts, and aggression is not an essential feature of a particular social group. This research hopes to inspire future studies to explore the association between social class and aggression more thoroughly. Additionally, it provides insights into how to reduce aggression among lower-class individuals.