Indeed, an enormous U.S. government study of the effects of child care6 found that what’s especially crucial is the mother’s or caregiver’s “sensitivity”—how attuned she is to her child’s experience of the world. “The sensitive mother is aware of the child’s needs, moods, interests, and capabilities,” a backgrounder explains. “She allows this awareness to guide her interactions with her child.” Conversely, having a depressed mother is very bad, because the depression stops the mother from tuning in to her child.

