One of the more entertaining discussions I've read about this is in Robert Wright's "The Moral Animal." There is a great discussion of monogamy, polygamy, and the circumstances that tend to generate both.
The thesis (as best as I can recreate it) is that monogamy comes naturally in hunter-gatherer societies, because there isn't much stratification (wealth can't be hoarded). So a 1:1 pairing makes economic sense. Polygamy tends to happen only in more stratified societies where wealth is unevenly distributed (if you need an answer for why some men would rather be poor in absolute terms in exchange for more wealth in relative terms, look no further). Because a very wealthy man may have multiple wives, weath distribution is more even for women than it is for men.
Then there are rare societies which have institutionally enforced monogamy with lots of wealth stratification. In these societies, wealth inequality between men will inevitably lead to substantial inequality between women as well. Suddenly, the stakes are much, much higher for women, which creates a far more competitive "marriage market." This is advanced as a theory for why, in American society, women tend to dress in flashy colors with elaborate displays, while the men tend to dress like penguins (the reverse of most of the animal kingdom) - it's a reflection of where the fiercest competition is taking place.
All of this is a "just-so" explanation, and isn't scientific, but still an interesting evoluationary and economic argument.
The thesis (as best as I can recreate it) is that monogamy comes naturally in hunter-gatherer societies, because there isn't much stratification (wealth can't be hoarded). So a 1:1 pairing makes economic sense. Polygamy tends to happen only in more stratified societies where wealth is unevenly distributed (if you need an answer for why some men would rather be poor in absolute terms in exchange for more wealth in relative terms, look no further). Because a very wealthy man may have multiple wives, weath distribution is more even for women than it is for men.
Then there are rare societies which have institutionally enforced monogamy with lots of wealth stratification. In these societies, wealth inequality between men will inevitably lead to substantial inequality between women as well. Suddenly, the stakes are much, much higher for women, which creates a far more competitive "marriage market." This is advanced as a theory for why, in American society, women tend to dress in flashy colors with elaborate displays, while the men tend to dress like penguins (the reverse of most of the animal kingdom) - it's a reflection of where the fiercest competition is taking place.
All of this is a "just-so" explanation, and isn't scientific, but still an interesting evoluationary and economic argument.