How important is it to the well-being of society? Is it merely a personal preference? Is it merely a Western ideal driven primarily by Christian belief? Or does it have larger, broader importance for a culture? This is a fascinating topic to examine for general students of the family and culture. Anthropologists tell us that around 85 percent of known societies through time have permitted multiple-partner marriage. Celebrated Rutgers anthropologist, Helen Fisher, tells us that only 0.5 percent of all polygamous cultures permit a woman to take many husbands. Men are the collectors of mates in both secular and biblical histories. But is monogamy, rather than a mere social construct, a greater social virtue and value?
A fascinating and brand-new multidisciplinary study conducted by a small group of psychologists, economists, and anthropologists from the University of British Columbia, UCLA, and UC Davis explores this very question. Their interest is why monogamy as a “historical rarity and apparent ill-fit with much of our evolved psychology” has spread so successfully throughout the world in recent centuries. A good question, especially since, they note, “the very men who most benefit from polygamous marriage — wealthy aristocrats — are often the most influential in setting norms and shaping laws.”
So why, as these authors ask, is monogamy “now enforced in most of the world’s highly developed countries”? Their answer? Sheer pragmatics. Normative monogamy — cultures enforcing exclusive, coupled marriage through law and social mores — provides dramatic and essential benefits for adults, children, and society. They offer four main benefits of keeping the bumble bee on one flower.
First, these scholars explain that monogamous marriage reduces sexual competition among men, reducing social violence and crime for many reasons. Most basic is that marriage itself tends to reduce the likelihood of men being violent and committing crime, reducing a man’s overall criminal likelihood by 35 percent. It reduces the likelihood of property and violent crime by males by 50 percent. This shows up time and again in the literature. This is because wives tend to socialize men, and monogamous marriage reduces a man’s testosterone levels, while polygamy has no such effect.
But polygamy shrinks the marriage pool for all but the wealthiest of men. This limits the socializing effect of having a wife, as well as creating greater anger, bitterness, and competition among the maritally shut-out men. In India, going from a male-to-female ratio of 1.12 to a more equalized 0.97 was shown to cut the societal murder rate in half! In China, increasing the ratio of men to women doubled their overall crime rate between 1988 and 2004. Not insignificant.
Second, monogamous marriage tends to increase relational equality, increasing female influence and standing in the relationship. When there is more competition for available women, men must seek younger and younger wives, securing them before their competitors do, creating more of a father-daughter, rather than a truly spousal relational balance. A 14-year-old girl being pressured to marry a 30-something man is no one’s idea of female empowerment. And a woman who has to compete with other women in a marriage is a less powerful party to the marriage. Most dramatically, a woman who is a commodity to be collected and controlled — as polygamy nearly always demands — has no standing at all.
Third, monogamy reduces conflict within the home because it doesn’t create competition and jealousy among co-wives, which the authors describe as “ubiquitous” in polygamous homes, even if Sister Wives tells us differently. And a comprehensive, cross-cultural review of psychological studies found that children from polygamous homes experience significantly greater amounts of conflict between their parents, household violence, and family instability than children being raised by monogamous parents. This is because monogamy creates a higher rate of relatedness — a tighter biological connection — between the members of the home. Polygamy creates more non-biological connections between various wives, their different children, and the increasing non-biological siblings. This naturally creates more family competition, resentment, and instability. As a result, these scholars explain that “living in the same household with genetically unrelated adults [sans adoption] is the single biggest risk factor for abuse, neglect and homicide of children.” (emphasis in original).
Fourth, monogamy increases paternal investment, significantly improving child-well-being outcomes as well as the lives of the fathers. Polygamy actually tends to reduce the paternal work of all men in two ways. It reduces the opportunity for middle and lower-status men to become fathers by shrinking the pool of available women. And the more wives and children a father has, the less time and energy he has to invest in each. This is really eroded when harem-dad’s child-rearing time and energy competes with his wife-procuring time. Wealthy, highly polygamous men often don’t know each of their children’s names because they can range in the 30s, 40s, or higher. Boys and girls in polygamous cultures are shown to have lower nutritional health and poorer overall survival rates, even though their fathers are wealthier.
Monogamy is sexual and familial democracy. Our authors explain without the slightest bit of apology or reticence that monogamy has been adopted by an increasing number of developing societies because “the supernaturally reinforced set of beliefs propounded by Christianity” found in monogamy lead to a “positive statistical relationship between the strength of normative monogamy with both democratic rights and civil liberties.” They continue, “Historically, we know that universal monogamous marriage preceded the emergence of democratic institutions in Europe and the rise of the notions of equality between the sexes.”
It’s nice when science pounds the pulpit for sexual restraint and commitment.
— Glenn T. Stanton is the director of Family Formation Studies at Focus on the Family and the author of (most recently) The Ring Makes All the Difference (Moody, 2011) and Secure Daughters, Confident Sons: How Parents Guide Their Children into Authentic Masculinity and Femininity (Multnomah, 2011)