Like everyone else does in the shower before work in the morning, I started wondering about family structures, the classical post WWII nuclear family, polygamy, matriarchy, etc., and how their development and formation in societies might be attributed to greater, and perhaps standardized, structural causes. As a result of the gay marriage debate there has been a lot of interesting talk about marriage and the family in American society, and I think its worth taking a look at marriage and family as institutions that change less because of purely cultural reasons but perhaps deep seated reasons of economy, geography, and all that other good stuff.
The starting point should be to examine current societies (not necessarily countries) and group them by marriage/family type. From here they should be categorized by various factors including the general makeup of the economy (i.e. developed industrial society, subsistence farming, hunter-gatherer, etc.). What factors predict that a society will have at root polygamy or instead “equal” monogamous marriages?
I do not think that the latter is the “natural” state of affairs, or god dictated state of affairs. However I am equally given to doubt the claims that marriage is a patriarchal construction without which we would be better off. As long as we allow ourselves to give any credence to normative values then it should be fair to debate whether certain forms of marriage/family work better or simply per se better.
My hypothesis sounds similar to the macroeconomic hypothesis (cited economist unknown) that birth rates decline with rising income primarily because as parents can afford things like education and health care for their children they tend to focus on supplying those goods in quality, rather than in quantity, and therefore focus their efforts on fewer children. This should not be misconstrued, but children are then inferior goods - to a point. The same might be said of marriage - not that it is inferior, but rather that as incomes tend to rise people can literally afford to put more leisure time into the relationship, with one person, and have less worry about a wife dying or an insufficient agricultural labor force.
Perhaps one day I will get around to looking into this question. Assuming of course that it has not already been answered in some anthropology dissertation.