Abstract Clinicians in Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies are rethinking whether Post-traumatic Stress Disorder (PTSD) is caused solely by exposure to life-threatening experiences, or also by moral injury—witnessing or participating in acts that violate moral beliefs. However, while there are evolutionary hypotheses explaining PTSD as a response to physical danger, the evolutionary roots of moral injury lack an explanation. We posit that a subset of symptoms of combat-related PTSD is associated with moral injury and that these symptoms evolved in tandem with human's norm-psychology. We can examine this hypothesis by comparing societies with different moral beliefs about warfare, norm enforcement mechanisms, and spheres of moral concern. To illustrate the utility of this framework, we describe combat trauma, war norms, and norm enforcement among Turkana pastoralist warriors in Kenya who participate in highly lethal raids of neighboring ethnic groups. We previously showed that depressive PTSD symptoms in Turkana warriors are more strongly associated with experiencing moral violations in combat, and that Turkana warriors with comparably high overall PTSD symptom-severity experience lower rates of depressive symptoms than US combat veterans. Here we detail aspects of Turkana warfare, moral beliefs, and post-battle rituals that differ from WEIRD societies, and that may ameliorate the symptoms of moral injury in Turkana warriors. Our findings highlight how further studies of combat trauma outside of WEIRD militaries can help evaluate this theory and illustrate the importance of cross-cultural research for identifying the evolutionary roots of combat stress and best practices for prevention and recovery.

中文翻译：

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来自图尔卡纳战士的洞察力的道德伤害进化论

摘要 西方、受过教育、工业化、富裕和民主 (WEIRD) 社会的临床医生正在重新思考创伤后应激障碍 (PTSD) 是仅由暴露于危及生命的经历引起，还是由道德伤害（目击或参与行为）引起的违反道德信念的。然而，虽然有进化假设将 PTSD 解释为对身体危险的反应，但道德伤害的进化根源缺乏解释。我们假设与战斗相关的 PTSD 的一部分症状与道德伤害有关，并且这些症状与人类的规范心理同步发展。我们可以通过比较在战争、规范执行机制和道德关注领域具有不同道德信念的社会来检验这一假设。为了说明这个框架的效用，我们描述了肯尼亚图尔卡纳牧民战士的战斗创伤、战争规范和规范执行，他们参与了对邻近民族的高度致命袭击。我们之前表明，图尔卡纳战士的抑郁 PTSD 症状与在战斗中经历道德侵犯更密切相关，并且总体 PTSD 症状严重程度相对较高的图尔卡纳战士的抑郁症状发生率低于美国退伍军人。在这里，我们详细介绍了图尔卡纳战争、道德信仰和战后仪式，这些方面与奇怪的社会不同，这些方面可能会改善图尔卡纳战士的道德伤害症状。