For all our obsession with race, class is asserting its predominance in these family trends. “College-educated blacks,” Putnam writes, “are looking more like college-educated whites, and less educated whites are looking more like less educated blacks.”

In part because of these family differences, there is an enormous, class-based parenting gap. “Increasingly,” according to Putnam, “parents from different social classes are doing very different things to and for their kids, with massively consequential results.”

More affluent parents tend to have the wherewithal to engage in the intensive nurturing best-suited to giving their children the social, emotional, and educational tools they will need to succeed later in life.

“The ubiquitous correlation between poverty and child development,” Putnam writes, “is, in fact, largely explained by differences in parenting styles, including cognitive stimulation (such as frequency of reading) and social engagement (such as involvement in extracurricular activities).”