On the Economics of Polygyny

Gary Becker devotes a chapter of his Treatise on the Family to Polygamy and Monogamy in marriage markets. The inclusion of polygamy in his analysis is more than an intriguing curiosum. Although overt polygamy is rare in our own society, it is a very common mode of family organization around the world. Of 1170 societies recorded in Murdock’s Ethnographic Atlas, polygyny (some men having more than one wife) is prevalent in 850. (Hartung, 1982). Moreover, our own society is far from completely monogamous. About 1/4 of all children born in the United States in 1990 were born to unmarried mothers who were not cohabiting with the fathers.1 Even though simultaneous marriages to multiple partners are not officially recognized, divorce and remarriage leads to a common pattern of “serial polygamy&”, in which males remarry more frequently than females and are more likely than females to have children by more than one spouse.2 This paper concerns the economics of polygynous societies with well-functioning markets for marriage partners. The institutions that we model appear to be particularly close to those found in the polygynous societies of Africa where polygyny is the norm. In the countries of the Sahel region of Africa, the percentage of women living in polygynous households ranges from 45% to 55%. In West Africa, Central Africa, and East Africa, these percentages are mostly in the range from 25% to 35%. In Southern Africa, polygyny is less common, with just under 10% of women living in polygynous households. (Lesthaege (1986)). Descriptions of these institutions can be found in Goody (1973) and in Kuper (1982). Most polygynous societies have positive prices for brides.3 In the polygynous societies of Africa, these prices, which anthropologists call “bridewealth”, are typically paid to the brides male relatives rather than to the bride. According to Jack Goody (1973, p. 5), “Bridewealth is not to be consumed in the course of the celebration, nor is it handed to the wife, it is given to the brides male kin (typically brothers) in order that they can themselves take a wife.” Dowry, in contrast to bridewealth, is a payment from the brides relatives. But according to Goody, dowry is not the “reverse” of bride wealth. Dowry typically goes directly to the newly married couple rather than to the relatives of the groom, constituting as Goody suggests, “a type of pre-mortem inheritance to the bride.” Goody distinguishes bridewealth from “indirect dowry.” , which is a payment from the groom’s family to the newlywed couple rather than to the bride’s male relatives. Goody reports that in polygynous African societies, payments at the time of marriage normally take the form of bridewealth rather than of indirect dowry. In human societies, males who inherit economic wealth from parents or other relatives can increase their reproductive success substantially by acquiring additional wives, mistresses, or concubines. For females, on the other hand, an extra husband adds little to her lifetime fertility. Once a female has achieved moderate prosperity, additional wealth does little to relax the biological constraints on the number of offspring she can have. Therefore, we expect that in an an economy with well-functioning markets for marital partners, where parents distribute inheritance and the the bridewealth of their daughters in such a way as to maximize the number of their surviving grandchildren, we would expect there to be polygyny rather than polyandry and we would expect brides to command a positive price. We would further expect to see parents leave their inheritances (including the bridewealth received for their daughters predominantly to their sons rather than to their daughters. According to Goody (1973) and Kuper (1981), most of the polygynous societies of Africa fit this description. In a polygynous society, one may want to distinguish the rights and obligations of full siblings from those of half-siblings who share the same father but have different mothers. In particular, it is useful to know whether males typically share the bridewealth of half-sisters or whether bridewealth is preferentially passed to full siblings. While the norm may differ across societies, Kupers book (p. 28 ) contains a beautifully explicit description of this pattern of property rights in traditional societies of southern Africa.