Over time, parents have barnacled the most routine activities in infancy with their own preoccupations. It’s sometimes hard to see the baby for all the barnacles.

You’d expect academics, people who are by training comfortable with complexity, to be the most resistant to the idea that we’re shaped by any single factor. In fact, they are often the worst offenders. Immersed...

We are at the tail end of a decline in infant mortality that began just over a century ago. Babies no longer wander into open hearths or are mauled by marauding pigs. We have vaccines,...

The psychologist Jerome Kagan has argued that parenting has a threshold function: up until that threshold is crossed, the effects of a child’s very early experience even out in the end. But parenting that crosses...