The moral psychology of killing in war

Abstract

How do people think about morality and war? Just war theory (JWT) is a philosophical theory which proposes a number of moral principles for how people should think about war (Walzer, 2006a). However, there are a number of unresolved debates in JWT, three of which I investigate in the present thesis. Although the debates in JWT concern prescriptive issues, I address these phenomena descriptively, from the perspective of moral and social psychology. The war paradox concerns the difference between moral judgments across war and peace contexts. To what extent is this difference influenced by the intergroup nature of war? And do all people make different judgments across peace and war contexts in the same way? The principle of discrimination states that soldiers are legitimate targets of violence in war, whereas civilians are not. Is this prescriptive rule reflected in the descriptive judgments of laypeople? And if moral judgments of soldiers and civilians actions differ, do judgments about their character do likewise? The independence thesis is a cornerstone of traditional JWT. According to traditional JWT, judgments about the conduct of war should be independent of judgments about the resort to war. That is, you may think that a country is engaging in armed conflict for the wrong reasons (a judgment that the resort to war was unjust rather than just), but you should nonetheless evaluate soldiers on either side of the conflict as moral equals. But when people make moral judgments about soldiers on the just or the unjust side of a war, do they in fact judge them symmetrically? In four experimental studies, I investigate these questions using scenarios (e.g. trolley problems) drawn from moral psychology. By manipulating various aspects of the war context – for example the identity of the soldiers and civilians involved, or the justness of the war for which they are fighting – I contribute a descriptive perspective on the war paradox, the principle of discrimination, and the independence thesis. In Study 1 (N = 263) and Study 2 (N =557) I find that moral judgments are slightly more utilitarian in a war context than in a peace context (the war paradox). However, the biggest influence of war on moral judgments is that in the war context participants find it more morally acceptable to sacrifice the lives of five outgroup members for the life of one ingroup member, compared to in the peace context. This intergroup bias is seen as more acceptable in war than in peace both by fellow ingroup members (Study 1), and by third parties (Study 2). In seeking to further explore the cognitive underpinnings of moral judgments in war and peace, I develop a method for assessing moral grammar (Study 2), which involves eliciting acceptability ratings in response to moral grammar statements derived from Action Trees. I use this method to test predictions from the linguistic analogy approach to morality (Mikhail, 2011). However, moral grammar does not relate to moral judgments the way the linguistic analogy presupposes; nor does moral grammar help account for the war paradox. The principle of discrimination (Study 3, N = 393) does emerge in lay people’s moral judgments: it is more morally permissible for soldiers to kill or be killed in a war context, than for civilians to kill or be killed. This discrimination between soldiers and civilians emerges also in judgments about their character: in this study I draw on research in person perception, mind attribution, and dehumanization to outline the stereotype of soldiers (relative to civilians), and find that soldiers are characterised by being particularly brave, cold, and harmful. On the other hand, a descriptive independence thesis (Study 4, N = 229) does not emerge in lay people’s moral judgments – that is, judgments of the conduct of soldiers on either side of the war are influenced by the justness of their side’s resort to war. The asymmetry of judgments of soldiers on either side of the war emerges in judgments of their actions (just soldiers are more permitted to kill than unjust soldiers) as well as in judgments about their character (the just soldier is seen as particularly brave, and the unjust soldier is seen as particularly harmful). The “moral equivalence of combatants” thus does not appear to hold neither for judgments about acts, nor for judgments about character. Throughout this thesis I discuss the implications of these findings for theories in social and moral psychology, as well as for JWT. I conclude that 1) philosophers working in the JWT tradition, as well as legal practitioners drawing on this theory (in the development of international laws, for example), should consider how lay people’s judgments align (or otherwise) with the prescriptive dictates of their theory, 2) moral psychologists should be careful in generalizing from “everyday morality” to war morality, as there are aspects of war morality that have no parallel in everyday morality (and the other way around), and 3) drawing on JWT and developing a descriptive account of the morality of killing in war, as this thesis does, complements and extends previous approaches psychology has taken to researching war.