In the early 2010s, researchers in Boston surreptitiously observed 55 caregivers eating with one or more children in fast-food restaurants. Forty of the adults were absorbed with their phones to varying degrees, some almost entirely ignoring the children (the researchers found that typing and swiping were bigger culprits in this regard than taking a call). Unsurprisingly, many of the children began to make bids for attention, which were frequently ignored. A follow-up study brought 225 mothers and their approximately 6-year-old children into a familiar setting and videotaped their interactions as each parent and child were given foods to try. During the observation period, a quarter of the mothers spontaneously used their phone, and those who did initiated substantially fewer verbal and nonverbal interactions with their child.

Yet another rigorously designed experiment, this one conducted in the Philadelphia area by Hirsh-Pasek, Golinkoff, and Temple’s Jessa Reed, tested the impact of parental cellphone use on children’s language learning. Thirty-eight mothers and their 2-year-olds were brought into a room. The mothers were then told that they would need to teach their children two new words (blicking, which was to mean “bouncing,” and frepping, which was to mean “shaking”) and were given a phone so that investigators could contact them from another room. When the mothers were interrupted by a call, the children did not learn the word, but otherwise they did. In an ironic coda to this study, the researchers had to exclude seven mothers from the analysis, because they didn’t answer the phone, “failing to follow protocol.” Good for them!