In human history monogamous relationships have not always been as popular as they are now. But according to a recent study, partner pairing provides a more productive and stable society—explaining perhaps why monogamy caught on.

According to a new article by the Philosophical Transactions of the Royal Society, ‘The puzzle of monogamous marriage,” around 85 percent of societies have allowed polygyny (the practice of a man having at least two wives at the same time) at some point in their history.

If it were not for the group benefits of monogamy, societies with unequal distributions of wealth should be more polygynous, because, as Christopher Shea from the Wall Street Journal Ideas Market blog summarizes from the article, “[i]t would be easier for men in the top 1% to support 3 wives, at least financially, than for a man in the lowest quartile of earners to support one.”

Yet in most societies today, especially those that are wealthy, monogamy is the cultural norm. The explanation from the authors is that monogamy, or at least a limit on the number of wives a man may take, reduces the number of men who are left single, and men unable to find wives are more likely to become violent outcasts. Also, the wealthy in a “polygyny-inhibiting” society will invest more into savings and child investment rather that finding wives. These factors lead to a monogamous society's relative flourishing.

“Reducing the pool of unmarried men and leveling the reproductive playing field would have decreased crime, which would have spurred commerce, travel and the free flow of ideas and innovations…. Higher status males, instead of seeking to attract additional wives, would make long-term investments and attend to their offsprings’ security,” the authors said.