توضیح فاصله بین پیش بینی تئوریکی و شواهد تجربی موجود در مورد سرمایه گذاری در سرمایه انسانی همسر

Economic theory that assumes personal income maximization predicts that a wife will under invest in her husband's human capital. However, casual observation of real life marriages and experimental evidences show that outcomes are more efficient than the theoretical prediction. This paper argues that the gap between the theoretical prediction and experimental evidences is due to inappropriate assumptions in the theory. That is, the bias in the theoretical prediction is caused by the neglect of the non-material factors that play crucial roles in marriage and the neglect of the fact that individuals may behave altruistically in marital decisions.

If maximizing personal income is regarded as the only motivation for an individual to invest in her or his spouse's human capital (for example, medical degree), then inefficient outcome will be concluded. A man would have an incentive to leave his wife after his wife has financed or supported his lucrative specialist education to reap the benefits from enhanced earnings capacity and, therefore, a clever wife would invest in her own human capital rather than investing in her husband's (Landes, 1978, King, 1982, Dufwenberg, 2002 and Oosterbeek et al., 2003). In that case, both the husband and wife are worse off than if the wife invests in her husband's human capital. However, the inefficient outcome predicted by the theory is not compatible with casual observation of real life marriages and experimental evidences. Experimental studies resembling the investment in the spouse's human capital show that the outcomes are more efficient than the theoretical prediction (Berg et al., 1995, Fdhr et al., 1997, Dufwenberg and Gneezy, 2000 and Oosterbeek et al., 2003). The theoretical analysis presented in this paper shows that the gap between the theoretical prediction and experimental evidences is due to inappropriate assumptions in the theory about maximizing personal income. Investments in the spouse's human capital are like business investments in the sense that they have material returns and are not risk-free. But they are different from business investments in the sense that marital investments are unavoidably influenced by love and other non-material (emotional and spiritual) factors that make marriage different from business partnerships. In many marriages, wives invest in their husbands’ human capital not only because they expect material return, but also because they love their husbands and intend to keep and improve the love relationships through the investments or simply because they want their husbands to be better off. Since non-material factors play an important role in marital decisions, neglecting non-material factors in the analysis of marital decisions is likely to lead to a biased, or even wrong, conclusion. The neglect of emotions in economic studies is typical (Elster, 1998). Dufwenberg (2002) argues that although the assumption that the spouses are motivated solely to maximize personal income is often accepted in economics, it needs to be appended. Gunning (1984) argues that it is not reasonable to assume that each partner seeks to maximize his or her income because partners want to exchange. Thus, a better analysis on the investment in the spouse's human capital requires that the non-material motivations being taken into account. Dufwenberg (2002) incorporates psychological guilt in a marital investment game and shows that if the payoffs reflect the spouses’ personal incomes only, low marital investment will result. However, if the husband is sensitive to guilt, high marital investment and a life-long marriage could possibly result. Although Dufwenberg focuses on the impact of guilt on marital investment and abstracts from all other issues, he points out that marital investment may be influenced by emotional or other motivational concerns besides guilt, such as companionship, esteem for spouse, erotic ties, and love. These non-monetary considerations have been emphasized by sociologists but seldom touched upon by economists. In order to incorporate non-material (emotional and spiritual) factors into the analysis of the investment in the spouse's human capital, I use the “material–spiritual goods framework” developed by Liu (2008), which can capture the non-material factors in marriage and disentangle non-material motivations from material motivations. I will show that the level of investment in the spouse's human capital is higher if non-material factors are taken into account than in the case where only personal income is maximized. Another problem of assuming maximizing personal income is that this assumption implies that individuals are self-interested in making marital decisions. Although individuals are self-interested, they may behave altruistically in the family because of love and other spiritual and emotional factors. Altruistic behavior in marriage has been modeled in different ways in the economic literature. In Samuelson's consensus model (1956), each partner has an individual utility function that depends on his or her private consumption, but the two partners agree to maximize a consensus social welfare function of their individual utilities subject to a joint budget constraint. In Becker, 1974 and Becker, 1981, if the husband cares about the wife, then the wife's commodity consumption enters the husband's utility function. In the collective model (e.g. Bourguignon and Chiappori, 1992, Browning and Chiappori, 1998 and Chiappori et al., 2002), altruistic family member’ utility depends on both partners’ consumption and the family maximizes the household utility function that depends on each member's utility, whereas egotistic member's utility depends on his or her own consumption and he or she maximizes his or her own utility subject to a sharing rule. To explore the consequence of the assumption about self-interested behavior, I will first study the investment in the husband's human capital motivated by the wife's self-interests, and then study the investment motivated by altruistic interests. Comparing the two cases, I find that an altruistic wife will surely invest more in her husband's human capital than a self-interested wife. The risk of divorce is an important factor in the investment in the spouse's human capital, because the investment would be efficient if the risk does not exist. The risk of divorce is treated as an exogenous factor in the related literature (King, 1982, Lommerud, 1989 and Rea, 1995). I treat the risk of divorce as an endogenous variable because the risk increases with the level of the spouse's human capital. A husband has an incentive to leave after his wife has financed or supported his lucrative specialist education (Allen and Brinig, 1998 and Dufwenberg, 2002). This positive relationship may be due to opportunistic behavior, or may be due to the fact that individuals’ preferences are likely to change after their income and social status increase. Another reason that I treat the risk of divorce as an endogenous variable is that the husband and wife can, although may not fully, control the risk through their effort. The wife who invests in her husbands’ human capital may manage to reduce the risk of divorce in two ways. One is through increasing the quality of the marriage. The investment may deepen the love between the couple, and thus increase the probability that the marriage will last a lifetime. The other way is through inculcating guilt to the husband who is supported. Individuals tend to feel guilty to abandon their spouses who have sacrificed themselves to support them (Dufwenberg, 2002). I assume that the couple cannot take loans to support the accumulation of human capital. That means, if a wife does not support her husband, the husband will not be able to accumulate human capital. I also assume that the family law does not protect the investments in the spouses’ human capital. If courts can divide human capital assets and entitle the women who have invested in their husbands’ human capital, outcomes would be more efficient (Borenstein and Courant, 1989 and Rea, 1995). I will present the model in Section 2 and conclude the paper in Section 3.

Economic theory that assumes personal income maximization predicts that a wife would under invest in her husband's human capital in the existence of risk of divorce. But casual observation of real life marriages and experimental evidences show that outcomes are more efficient than the theoretical prediction. By using a material–spiritual goods framework, I demonstrate that the gap between the theoretical prediction and experimental evidences is a direct result of the assumptions in the theory. In other words, the gap can be explained by the neglect of non-material factors and the neglect of the fact that individuals may behave altruistically in marital decisions.