Attitudinal and Behavioral Legacies of Wartime Violence: A Meta-Analysis

Understanding the legacies of wartime violence is essential for explaining postwar dynamics and informing policy. I present a meta-analysis of 172 quantitative studies across more than 50 countries, assessing the effects of wartime violence on 22 outcomes spanning four broad areas: (a) civic and political engagement, prosociality, and trust; (b) attitudinal hardening toward wartime enemies; (c) identification with one’s own wartime-aligned group; and (d) generalized attitudinal hardening. The analysis reveals mixed effects on engagement, prosociality, and trust: while violence increases some forms of participation, it does not promote voting, trust, or altruism. In contrast, wartime violence consistently heightens hostility toward former adversaries and strengthens in-group identification and favoritism. However, I find little evidence of broader hardening toward actors not directly involved in the conflict. These results challenge optimistic claims that war fosters cohesion and underscore the need for interventions that reduce intergroup hostility, rebuild cross group-trust, and support reconciliation.