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,...

The historical record knows only few instances of democracies waging war against each other. Therefore, democratization is considered key in achieving global peace. However, efforts to achieve sustained democratic governance often fail-Afghanistan being a recent example. Democratization appears...

The scale of violent intergroup conflict in humans is astonishingly large compared to other mammals [1, 2, 3, 4]. This capacity for war is closely linked to our exceptionally cooperative abilities [5, 6]. The parochial altruism model formally describes how within-group cooperation and...

The historical record knows only few instances of democracies waging war against each other. Therefore, democratization is considered key in achieving global peace. However, efforts to achieve sustained democratic governance often fail-Afghanistan being a recent example. Democratization appears...