TY - JOUR
T1 - An evolutionary theory of moral injury with insight from Turkana warriors
AU - Zefferman, Matthew R.
AU - Mathew, Sarah
N1 - Funding Information:
This research was funded by an Andrew Carnegie Fellowship to SM from the Carnegie Corporation of New York. Additional support was provided by a Donald R. Beall Defense Fellowship to MZ through the Naval Postgraduate School Foundation. The Archaeology Section of the Earth Sciences Division of the National Museums of Kenya provided institutional support. Turkana interview survey questions were validated and administered with the help of Turkana fieldsite manager Gilbert Eweet Topos and research assistants Ekiru Alvos Calystus, Lilian Amuria Lotiira, Dismas Ekitoe Lomukuny, and James Muya Chegem. We thank Katie Hinde, Devon Hinton, Bonnie Kaiser, Brandon Kohrt, Brian Litz, Eric Meyer, Randy Nesse, Bilinda Straight, Ben Trumble, and Polly Wiessner for early discussions about this project, and Emily Zefferman and four anonymous reviewers for manuscript suggestions. We especially thank our research participants and Turkana host communities.
Funding Information:
This research was funded by an Andrew Carnegie Fellowship to SM from the Carnegie Corporation of New York. Additional support was provided by a Donald R. Beall Defense Fellowship to MZ through the Naval Postgraduate School Foundation. The Archaeology Section of the Earth Sciences Division of the National Museums of Kenya provided institutional support. Turkana interview survey questions were validated and administered with the help of Turkana fieldsite manager Gilbert Eweet Topos and research assistants Ekiru Alvos Calystus, Lilian Amuria Lotiira, Dismas Ekitoe Lomukuny, and James Muya Chegem. We thank Katie Hinde, Devon Hinton, Bonnie Kaiser, Brandon Kohrt, Brian Litz, Eric Meyer, Randy Nesse, Bilinda Straight, Ben Trumble, and Polly Wiessner for early discussions about this project, and Emily Zefferman and four anonymous reviewers for manuscript suggestions. We especially thank our research participants and Turkana host communities.
Publisher Copyright:
© 2020
PY - 2020/9
Y1 - 2020/9
N2 - 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.
AB - 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.
KW - Combat stress
KW - Evolutionary medicine
KW - Moral injury
KW - PTSD
KW - Post-traumatic stress disorder
UR - http://www.scopus.com/inward/record.url?scp=85089141236&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85089141236&partnerID=8YFLogxK
U2 - 10.1016/j.evolhumbehav.2020.07.003
DO - 10.1016/j.evolhumbehav.2020.07.003
M3 - Article
AN - SCOPUS:85089141236
SN - 1090-5138
VL - 41
SP - 341
EP - 353
JO - Evolution and Human Behavior
JF - Evolution and Human Behavior
IS - 5
ER -