David Geary Ph.D.

Male, Female

Do Women Fight?

Female-female competition in an evolutionary context.

Posted Aug 29, 2019

When it comes to competition and conflict, men seem to get the lion’s share of the credit. In Darwin’s 1871 landmark publication on sex differences, he focused on male-male competition for mates and female choice of mating partners. These were not unreasonable foci, because these aspects of mating dynamics are very common across species and are typically much more obvious than their counterparts of female-female competition and male choice.

In recent decades, however, it has become clear that competition among females is common. The competition is essentially over access to and the control of resources that improve their survival prospects and those of their offspring, whether these resources are mates or high-quality foods. Among primates, female-on-female aggression is quite common and indeed there is no consistent cross-species sex difference in the frequency of aggressive encounters. In some species, females are relatively more aggressive than males and in other species males are relatively more aggressive.

In the vast majority of species, female-female competition is subtler, less risky, and oftentimes more strategic than male-male competition. Escalation to potentially injurious physical fights does not yield the same benefits as it does for males and likely results in reproductive costs to females. The strategic component means that female-female competition will be more variable across contexts, depending on local social and ecological (e.g., food availability) conditions.

We see this same pattern among adolescent girls and women, whereby the dynamics of competition can be expressed among single women in monogamous societies or among co-wives in polygynous marriages. The competition can manifest in many different ways, as with men, including the enhancement of traits that men find attractive to the social manipulation and exclusion of potential competitors to (more rarely) physical violence. In societies with socially-imposed monogamy, women’s financial contributions to the marriage (e.g., dowry) can be another form of female-female competition. I focus here on the dynamics of women’s aggression in the context of social relationships.

Women have evolved to attempt to create networks of social relationships that provide them and their children with social and emotional support and that enhance their access to and control of culturally-important resources. The nature of these networks can vary from nuclear families (e.g., husband, wife, and children) to female-biased families (e.g., mother, grandmother, children), but whatever form they take women who are successful in developing and maintaining them have healthier children and more surviving children. These networks, of course, are also found among young and adolescent girls and single women; their best friends are often at the center of this support network.

Competition among women is often focused on the disruption of these support networks, as related to access to relationships with other girls (best friends) and sometimes would-be boyfriends or husbands. Rather than pushing, shoving, and physical bluster, as with boys and men, women’s attempts to organize the social world to suit their interests often involves gossip. Girls’ and women’s gossip typically focuses on same-sex friends, same-sex foes, or potential romantic partners. The gossip helps girls and women to form the friendships that provide them with social and emotional support, but it is also a primary means of undermining potential competitors.

The latter involves social tactics that are called relational aggression. This form of aggression can be an effective strategy, because humans are a highly social species and are dependent on the social support and goodwill of others in their community. Relational aggression is an attack on another individual’s core relationships and an attempt to undermine their wider social capital (e.g., the extent to which others trust them). When effective, relational aggression will erode the strength of victims’ interpersonal relationships, including romantic relationships, and isolate them from the support of other members of the local community. These would be serious consequences in the small-scale communities that comprise traditional cultures.

Relational aggression is primarily focused on same-sex peers and is basically a form of status striving that functions to provide competitive advantage over the victim. The behaviors include withholding positive information about competitors and strategically using negative information (e.g., they have been unfaithful to a romantic partner) against rivals, whether or not it is true, in the context of gossip. These strategically placed bits of information function to undermine the status and attractiveness of same-sex competitors and to exclude them from the social group. If done well and judiciously, engaging in gossip can also enhance one’s own status within the group or solidify existing friendships.

To be sure, both sexes use relational aggression to undermine the attractiveness of competitors to romantic partners, with men derogating the cultural success (e.g., income) of competitors and women derogating the attractiveness and sexual fidelity of competitors. Men also use relational aggression as a means to move up the male hierarchy by questioning the ability of their rival to contribute to the overall goals of the group (e.g., win a competition). At the same time, relational aggression can be especially damaging among girls and women. This is because they reveal more personal and potentially embarrassing information to their best friends and are more dependent on these forms of intimate same-sex relationships for social and emotional support than are boys and men. The heightened interpersonal intimacy among girls and women comes at a cost of greater vulnerability to social manipulation and other forms of relational aggression should the relationship dissolve, as it often does.

In one large-scale study, Bond et al. (2001) found that girls who are victimized by relational aggression are 2.6 times more likely to later suffer from depression or anxiety than are girls who are not victimized or boys who are victimized. The risk for girls continues into adulthood and is especially high if the girl or woman is isolated–isolation is a goal of relational aggression–from friends and family. Girls and women who capture the attention of the opposite sex are often targets of relational aggression. A study of more than 2,000 adolescents confirmed higher levels of depression in the victims of relational aggression and that physically attractive girls, but not boys, are victimized more often than their less attractive peers. In this study, an adolescent girl at the 80th percentile of attractiveness received 35% more derogatory remarks either directly or through gossip than did girls of average attractiveness, and this increased to 70% more derogatory remarks for the most attractive girls.  

Sometimes relational aggression works. LaFontana and Cillessen (2002), for instance, found that as children move into adolescence many aggressive girls achieve social visibility and influence. Socially aggressive and popular peers, however, are not always well liked, especially by other girls. For adolescents, Smith and colleagues (2010) found that relationally aggressive adolescent girls largely directed their aggression toward other girls and were more popular among boys than were other girls. We might speculate that these aggressive girls used different social tactics in their relationships with other girls as compared to their relationships with boys. Whatever they are doing, their social skills provide them with an advantage in the context of their peer group.

Social manipulation and an occasional fight over a would-be boyfriend or husband in a modern nation with socially-impose monogamy is one thing, but competition among co-wives or with other women (e.g., sister- or mother-in-law) in polygynous households or compounds is often at another level of seriousness. Polygyny is common across human societies, has been an important feature of human evolution for at least 4 million years, and may be the core context in which relational aggression evolved. In these contexts women often have to contend with the competing interests of the other wives of their husbands, as well as with their husbands’ female kin if they move into his village. The nature and intensity of this competition varies with whether or not a co-wife is a sister, the extent to which co-wives must cooperate to produce food, and oftentimes age differences between the women, but is often quite intense

Burbank’s survey of 137 traditional societies indicated that verbal abuse and insults are the most common form of women’s aggression. “One of the most striking findings of this survey is that women are by far the most common targets of female aggression … The most frequent contenders are co-wives, sexual revivals, a wife, and the ‘other woman’” (Burbank, 1987, pp. 82-83). The most common instigators of arguments among co-wives are jealousy, unequal treatment by the husband, and the introduction of a new co-wife into the family. The addition of a co-wife often triggers physical fights among the co-wives, as this results in a substantial reduction in the amount of resources that each of the co-wives will receive from their husband. In effect, most polygynously married men do not have the material and emotional resources needed to meet the expectations of each of their wives, and this shortfall is what drives the competition among them.    

Strassmann (1997, 2011) provides one of the more thorough assessments of this pattern, with her study of the lifetime reproductive success of monogamously and polygynously married Dogon (Republic of Mali) women. For women, the reproductive disadvantage of polygyny is largely due to a sharply higher mortality rate for their children: even with increased mortality, men still reproductively benefit from polygyny. The premature mortality was not due to diminished resources per child, but may have been related to less paternal investment and the resulting competition from co-wives for the investment that was provided. “In addition to neglect and mistreatment, it was widely assumed that cowives often fatally poisoned each other’s children…Cowife aggression is extensively documented in Malian court cases with confessions and convictions for poisoning” (Strassmann, 1997, p. 693).

Murdering the children of co-wives not only increases the immediate resources available to their own children, but it also reduces the number of heirs to their husbands’ land. This is because sons inherit and divide the land of their father and therefore the sons of co-wives are direct competitors for the land each woman’s sons will need to attract wives. This competition may explain why the mortality of Dogon boys is 2.5 times higher than that of their sisters. Ji et al.’s (2013) study of the Mosuo (China) confirms the importance of resource control for women’s reproductive success. In this matrilineal society, women live with their sisters in family compounds and thus they, not co-wives, are the primary competitors for resources produced by the family’s farm. As the number of sisters increases, the number of children each woman has decreases, especially among younger and subordinate women. Other studies suggest that competition among co-resident women who are not co-wives (e.g., wives of brothers) is particularly important during the child’s first two years of life, when mortality risks are the highest.

The point is that women do indeed fight, although often in a subtler manner than fighting among men. In traditional contexts and likely throughout human evolution, much of this hostility was directed toward other women and focused on gaining access to resources that could substantively influence their well-being and that of their children, as is common with female-female competition across species. In the modern world with greater integration of women into the economic and political spheres traditionally occupied by men, women’s relational aggression has blossomed to include men who are perceived as competitors. Many men miss the (at times) subtleness of this form of aggression and often don’t realize what is happening or how to respond. Some men might even withdraw from these spheres, which of course is the goal of relational aggression.

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