The rise of monogamy

Sadettin Haluk Citci

doi:10.1007/s13209-014-0113-y

Abstract

Why has polygyny, marriage of a man to multiple women, common in most societies throughout history, almost disappeared in modern industrialized countries? Do women play a role in its disappearance? A simple theoretical model suggests that at the later stage of the transition from polygyny to monogamy, the spread of human capital and the increase of labor income have led to the rise of monogamy. A general equilibrium model of the marriage market illustrates that the spread of human capital results in an increase in women’s income opportunities and lowers the importance of bequests in determining their sons’ incomes. Both effects improve women’s outside option, mating monogamously, and decrease the marginal benefit of the economic advantages provided by polygynous unions. This, in turn, reduces polygyny by increasing the cost of polygynous mating for men. When the human capital level is sufficiently high, men find it optimal to marry monogamously instead of bearing the high cost of polygynous mating.

Highlights

Polygynous mating is a global phenomenon in the sense that it has occurred in most societies throughout history
A common feature of developed economies is that the level of human capital and, relatedly, the average labor income in these countries are much higher than they are in less developed countries
I further assert that, through the process of industrialization and economic development, the spread of human capital and the increase of labor income have led to the virtual disappearance of polygyny at the later stage of the transition

Summary

Introduction

Polygynous mating is a global phenomenon in the sense that it has occurred in most societies throughout history. Betzig (1995) writes that “When, why did polygyny and despotism end, and monogamy and democracy begin?...It seems to me that one event changed all that: the switch to an industrial economy in Europe in the past few centuries.” This timing fits well with the spread of human capital and the increasing role of women both in the economy and in marriage decisions. In an economy where the level of human capital and, relatedly, the value of women’s income opportunities (excluding the economic transfers provided by their mates) such as labor income are low, a rich man can persuade a woman to become involved in a polygynous union instead of marrying monogamously by offering few economic advantages for her or her children. The increase of return on human capital and labor income decreases the marginal benefit of the economic advantages provided in polygynous unions and leads to a substantial increase in the cost of polygyny for men.

The model

Analysis

Robustness

Findings

Conclusion