ABSTRACT
C onict and aggression appear to be one of the de–ning features of our species. Humans –ght, argue, and engage in intraspecies violence at a rate that seems to be unique among species. Human history seems so replete with amazing feats of intraspecies conict and violence that some theoreticians such as Arthur Koestler (1972) even believed that killing our own has always been and continues to be a de–ning feature of all human societies, from the distant historical past to the present. The ancient Maya thought nothing of ripping out the living hearts of tens of thousands of captives in a single day; thousands of civilians were killed a few years ago in Bosnia simply because they belonged to the wrong ethnic group; Islamic terrorists seem to rejoice in the murder of thousands of innocent civilians in the name of ideologies that most of us brought up in the liberal, rational, Western tradition would consider bizarre and incomprehensible at best (see also Kruglanski & Orehek; Kurzban & Christner; Van Vugt, this volume). Explaining the roots, features, and consequences of the way human beings engage in conict and aggression has thus been a de–ning concern for writers and
philosophers since antiquity. This volume seeks to present some of the most recent leading-edge psychological research and thinking on this perennial topic from a group of distinguished international researchers.
