As evidence of how social standards have changed, Kearney and Wilson describe how people living in Appalachian coal-mining communities responded in a quite different way to a similar economic boom in the 1970s and ’80s. Back then, spikes in income led to dramatic increases in marriage and the proportion of births within marriage—the very things that apparently have failed to resurge in today’s boomtowns. The way that most couples decide matters of marriage and children nowadays, Kearney and Wilson argue, has taken on a momentum of its own, one that short-term improvements in the economy won’t easily redirect.

This model may seem to focus unduly on men’s economic prospects, compared to women’s, but that’s actually the point. Americans still on the whole expect men to provide, meaning their worth as partners is more closely tied to their income. In fact, what seems to be decisive in Autor, Dorn, and Hanson’s study is not really whether men’s incomes go up or down, but whether they go up or down relative to women’s. For instance, when competition from China chipped away at jobs in female-dominated manufacturing sectors, such as the leather-goods industry, marriage rates actually increased. As women’s wages fell compared to men’s, the economists argue, marriage was more likely to lead to economic security, and single motherhood became less attractive.