The logic of human intergroup conflict: Knowns and known unknowns

Human history as well as our present are ripe with violent intergroup conflicts. Despite more than 2,000 years of academic engagement with this phenomenon [1] and (way too) much evidence available for analysis [2], we are still short of
encompassing theories of human belligerence. Not least, theoretical progress is thwarted by the fact that intergroup conflict is an interface phenomenon: its analysis requires the methods and background knowledge of several academic
disciplines. This review pushes for intensified interdisciplinary integration in the study of human warfare. It does so by presenting a selection of pathbreaking theoretical contributions from economics, political science, social psychology, and
evolutionary biology, and contrasting their respective insights and blind spots against the results of recent empirical work on human behavior before, during, and after war. As a result, three key areas are identified where theoretical breakthrough
is still pending: (i) individual mobilization, (ii) the ambiguous roles of leaders, and (iii) the endogenous and dynamic interaction between conflict and its participants’ malleable preferences. Thus, this review provides an overview of
the research frontier and highlights crucial challenges in the theoretical study of human warfare.