11/19/2014 05:19 pm ET Updated Jan 19, 2015

Women and Warfare in Human Evolution

Evidence suggests that warfare is an ancient part of human life, dating back to when all humans lived as hunter-gatherers. Scientists who study the evolution of the human mind have paid considerable attention to the challenges that warfare posed for men and how it might have shaped male minds, but not to the effects that it might have had on women. This invites the question: What were those effects, and how might they have shaped female psychology?

An overlooked source of data on this question is the oral traditions of indigenous foraging peoples collected by explorers and anthropologists over the last few centuries. In forager groups, warfare takes the form of lethal raiding -- a brief, surprise attack on a neighboring group by a coalition of males, followed by a hasty retreat to their home territory. Anthropologists have long noted that forager war narratives contain accurate descriptions of lethal raiding tactics and practices. Since our ancestors were foragers as well, these narratives are one of the best models we have of what warfare might have been like in early human groups. To date, however, no one has used them to study cross-cultural patterns in forager warfare.

One of the patterns these stories illuminate is the recurrent costs of warfare for women. Because war narratives often mention casualties, they show us multiple ways in which lethal raiding affected forager women and, by extension, our female ancestors. The catalog of casualties includes rape, torture, forced concubinage, enslavement, and death, but these are only the most obvious costs. In small-scale societies, support networks are largely kin-based. Thus, the death of a husband, father, brother, or other close kinsman in battle meant the loss of an important source of protection for a woman and her dependent children. On this last point, perhaps the most painful casualty suffered by women was the loss of offspring: Many stories recount the death or capture of children in battle.

To determine just how widespread these casualties were, I surveyed a sample of oral traditions from 45 different societies for five different costs. I chose costs that cropped up repeatedly, not only in oral tradition but in ethnographic and archaeological research: the death of a woman, the capture of a woman, the death or capture of a husband, the death or capture of an adult male kinsman, and the death of a child. Over 80 percent of the traditions contained a story that mentioned at least one of these casualties.

These findings suggest that warfare regularly imposed costs on women as well as men and point to problems that were particularly acute for women. For example, men were typically killed in raids, but because of their desirability as wives, women and girls were often taken captive instead. This was reflected in the survey: Forty-four percent of the narratives referenced the death of a woman, while 49 percent referenced female capture. For women, then, it was important to assess the intent of an assailant -- to weigh the probabilities of being killed against those of being captured, and the comparative risks of resistance vs. compliance. When captured, a woman faced the additional problem of evaluating her chances of escape and, while awaiting such an opportunity, trying to secure humane treatment from her captor and his people.

The widespread practice of taking captives in forager warfare casts Stockholm syndrome in a new light. This term refers to the sympathetic feelings a hostage may develop for a captor and his views. Occurrence of this syndrome is associated with physical restraint or confinement and the threat or actual administration of physical, sexual, or emotional abuse -- conditions that are typical of forager captivity. Commonly characterized as an illness, this response may instead be an evolved strategy for increasing a captive's chances of survival through acute assimilation. Rapid adoption of the beliefs and practices of one's captors may terminate or lessen abusive behavior. Recent captivity incidents support this interpretation by showing that resistance is met with maltreatment. For example, many women and girls taken by Boko Haram claim that they were threatened with or subjected to psychological and physical abuse (including death), forced labor, forced marriage, and other forms of sexual abuse if they refused to convert to Islam. Some forager war narratives recount successful rescue attempts, pointing to another side effect of warfare for women: the task of reintegrating into one's natal group after (literally) sleeping with the enemy.

Forager war narratives document an aspect of human experience that has been overlooked in the study of human evolution: the costs that warfare imposed on women. Many of these problems remain with us to this day. Thus, understanding how these problems shaped our past may help us address them in the present.

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