It is always sobering to learn how emotions like love are the results of hormones and chemical processes. So it is no surprise that a hormone is responsible for the strong bonds that one feels for someone else. Oxytocin for females, vasopressin for males are the recipes for mutual love and respect. But what does this have to do with Economics?
Plenty. Think about the institution of marriage. In societies where there is little wealth inequality, one should expect most marriages to be monogamous: no single man (or woman) can provide for more than one spouse when competiting with the other suitors. Thus, hunter-gatherer societies are characterized by serial monogamy, as individuals did not have the ability to gather any wealth.
But in agricultural societies, wealth is accumulated, and thus wealth disparities can arise. As societies are mostly patriarchal, it is usally some men that can have multiple spouses. This equilibrium is both economic and biologic: rich men can guarantee the survival of more offspring. But it turns out that the correlation between agricultural development and prevalence of polygyny is negative. Thus, something else must be dominating the wealth effect as described above.
Marina Adshade and Brooks Kaiser suggest that the reason lays in the presence of oxytocin in some agriculture production. In particular, oxytocin is released during lactation, the evolutionary reason being that it creates affection of the mother for her child (thereby sobering me even more). Therefore, the use of milk products should favor monogamy, as oxytocin is not unique to humans. Indeed, a regression between the prevalence of monogamy aganst the prevalence of milking, soy and oilseed production (the later also producing oxytocin) as well as other controls yields a positive coefficient.
Further economic consequence: if monogamous marriage is to be considered a good institution, for example because it reduces the tension stemming from frustrated males, governments should promote and subsidize milk consumption...
PS: Sorry for the hiatus. Exams were taking much of my time.