Men’s Parenting

In a previous post, I discussed the evolution of men’s investment in their children. Recall, understanding how men’s parenting evolved is important because most male mammals invest little if anything in their offspring, including our two closest relatives (chimpanzees and bonobos). Although a bias to invest in children has evolved and men’s investment can provide important benefits to children, it isn’t guaranteed. Some men invest as much or more than the children’s mother and other men invest nothing at all. This is called facultative investment, that is, whether the man invests or not depends on a variety of factors. These factors range from biological influences to relationship dynamics to wider social and cultural mores.

It won’t be a surprise to learn that men’s testosterone levels will influence their priorities; specifically, how much time and effort they invest in seeking romantic partners as opposed to settling down and investing in children. It is not as straightforward as it seems, however, because men’s testosterone levels can change with the nature of their relationships. The testosterone levels of men in committed and happy relationships drop to levels that reduce their interest in other women and increase their desire to have and invest in children. If the relationship turns sour, however, men’s testosterone starts to rise to levels that can result in a disengagement from the relationship and any children, and spark a search for a new partner.

It’s not simply testosterone though, because there are several social factors that also influence how much men invest in their children. As noted, men who are satisfied with their relationship have lower testosterone levels and therefore are much more engaged with their children than are other men. In fact, one of the most important influences on men’s engagement with their children is the quality of their relationships with the children’s mother. Some men of course stay highly engaged with their children, even when their marital relationship is fraught with tension, but many men disengage from the marriage and their children during times of conflict.

There are wider factors as well, the most important being the social rules for marriage. Although most Western nations have a social tradition of monogamous marriage and legal penalties for simultaneously marrying two or more people, this is not the norm in many other contexts. The vast majority of traditional cultures as well as many developed nations today allow for polygynous marriages. A common pattern would be for the most successful 10 to 20 percent of men to be married to two or more women. As one might imagine, this greatly complicates marital dynamics, because co-wives aren’t typically BFFs and often work to undermine the other co-wives’ relationships with their husband and are often hostile to the children of these co-wives. Living in such a society also influences men’s priorities. Married men do not show the drops in testosterone levels that is common among married men in monogamous societies. When polygyny is an option, men stay on the lookout for their next bride, even after they are married. This shift also means that their annual bonus check will go toward finding this new bride rather than investing in their current children’s college fund.

In other words, the legal and social suppression of polygyny significantly changes marital dynamics and men’s investment in their children, among other things (e.g., reduces male-on-male violence). Even in monogamous societies, other social factors can influence whether men are biased toward a committed marriage and investment in children or whether they delay marriage and pursue short-term sexual relationships. The most important of these is the operational sex ratio, that is, the ratio of unmarried men to women. During periods when there are more women than men looking for partners–such as from 1965 through the 1970s in the United States–men’s mating opportunities increase and their investment in marriage and parenting decrease. These historical periods are generally characterized by liberal sexual mores (i.e., many sexual partners for both men and women), high divorce rates, an increase in the number of out-of-wedlock births and the number of families headed by single women, an increase in women’s participation in the workforce, and generally lower levels of investment in children.

A different pattern emerges when there are too many men. Here, women are better able to enforce their preference for a monogamous, high-investment spouse. As a result, these historical periods are generally characterized by an increase men’s commitment to marriage, as indexed by declining divorce rates and greater levels of investment in children. Moreover, when there are too many men, women demanded more–in terms of wealth–before they marry and they typically get it. Men are motivated to work harder and to achieve economic success, because without this they are much less likely to be chosen as a groom.