Polygyny, Fertility, and Savings

Abstract

Sub-Saharan Africa has a high incidence of polygyny. Countries in this region are also characterized by large age gaps between husbands and wives, high fertility, and the payment of a brideprice at marriage. In monogamous countries, on the other hand, the bride's parents traditionally give a dowry (negative brideprice) at marriage. Sub-Saharan Africa is also the poorest region of the world. In this paper I ask whether banning polygyny could play any role for development in Sub-Saharan Africa. Since this experiment does not exist in the data, I address the question using a formal model of polygyny and analyze the effects of enforcing monogamy within the model. I find that enforcing monogamy lowers fertility, shrinks the spousal age gap, and reverses the direction of marriage payments. The capital-output ratio and GDP per capita increase. The reason is that when polygyny is allowed, high brideprices are needed to ration women. Buying wives and selling daughters becomes a good investment strategy that crowds out investment in physical assets. I show that these effects can be large quantitatively. For reasonable parameter values, I find that banning polygyny decreases fertility by 40%, increases the savings rate by 70% and increases output per capita by 170%. * This is a chapter from my Ph.D. Dissertation at the University of Minnesota. It was previously circulated under the title "Polygyny and Poverty." This research was funded through a Doctoral Dissertation Fellowship from the University of Minnesota and an NSF grant. I am especially grateful to Larry E. Jones for his advice and encouragement. I would also like to thank Michele Boldrin, V

What do men want? Re-examining whether men benefit from higher fertility than is optimal for women

“…women in worse condition become later wives to polygynous men [71,72]. This may help explain why we see the opposite effect at the group level; polygynous societies have higher total fertility rates than monogamous ones [28]. These differences seem to be driven primarily by the higher demand for women, which reduces the number of unmarried women and pushes their age at first birth down, thus extending women's reproductive lifespan [73].…”

“…Several studies have reported that women in polygynous households have lower fertility than their monogamous counterparts in the same society [26,27], but polygynous societies tend to have higher fertility than monogamous ones [28]. Some evolutionary scholars interpret this higher fertility as being against women's interests, but are ambiguous whether it is specifically against her fitness interests [13].…”

The rise of monogamy

“…Moreover, polygyny is not an issue of the past. We still observe polygynous marriage at a rate of up to 55 % in many sub-Saharan African countries (Tertilt 2005). For example, the percentage of married men in a polygynous union is 55 % in Cameroon and 40 % in Senegal and Burkina Faso.…”

Marriage Markets in Developing Countries

“…In a similar vein, Tertilt (2005) uses an overlapping-generations model to examine if polygyny can explain the low levels of development in sub-Saharan Africa. In her model, the return on daughters is positive due to bride price, while the return on sons is zero.…”