take an alternative approach to the question of why children growing up with their own two married parents do better than children growing up without their fathers. It’s not marriage that makes the difference for kids, they argue; it’s the kind of people who marry. Mothers who marry and stay married already have the psychological endowment that makes them both more effective partners and more competent parents.
Hymowitz goes on to make the most important point, I think, about the psychological, or really, the cultural advantage that women (and men) who stay married have:
key part of that difference is that educated women still believe in marriage as an institution for raising children. What is missing in all the ocean of research related to the Marriage Gap is any recognition that this assumption is itself an invaluable piece of cultural and psychological capital—and not just because it makes it more likely that children will grow up with a dad in the house.
This question of which matters more, material resources or the cultural inclination to use them, is one of the deepest and most enduring puzzles in sociology and in social life. Max Weber, following Goethe, uses the phrase "elective affinity" to explain how both of these factors work together and work at the same time. People who are inclined to act a certain way are drawn to social institutions in which other people also act that same way. And being in an institution which rewards a certain kind of action molds the people in it to value that kind of action even more. Elective affinity is, to my mind, one of the deepest, richest, and most mysterious features of social life. We both shape and are shaped by social institutions. Birds of a feather flock together – which makes them more of a feather.
So how does this play out in marriage? Marriage confers huge material advantages. People who stay married normally reap rich benefits, for themselves and their children. And the experience of marriage teaches people how to live with others, to accommodate and compromise and take pleasure in serving one another. But marriage is also a risk and a leap. People who already know how to accommodate and serve, and who trust in the whole institution of marriage in the first place, are more likely to take the risk. SO, people with both the cultural and psychological predisposition and a good material and psychological experience are likely to reap the greatest advantage from their marriages. But whatever you bring to marriage, you are likely – not guaranteed, but likely – to reap a proportionate benefit. Elective affinity multiplies the effect of social institutions, perhaps in marriage most of all.