An early fear of strangers is common, but some parents told me they worry it has been amplified during the pandemic—that their children haven’t learned to socialize. Nora has come to adore her grandmother, but with other adults, she seems to warm up only after they lower their masks so she can see them smile. And with other toddlers, she can be standoffish. For very young children, though, spending time with peers is a relatively recent phenomenon. “Years ago, most kids were not in preschool programs. They had peer interactions with siblings, with neighbors,” but many spent their first couple of years in an environment of adults, Jack Shonkoff, a pediatrician and the director of the Center on the Developing Child at Harvard, told me.

Social interaction becomes more meaningful in the second and third years of life, as children learn to separate from their grown-ups and see themselves as individuals. “If children haven’t had [social] experience when they enter into preschool, they need some extra scaffolding from their teachers and parents to learn … about taking turns and sharing and solving conflicts,” the psychologist Nancy Close, of the Yale Child Study Center, told me. No toddler is good at those things—and for children who have interacted very little with others, it may take a little more time. Force suspects that Nora will be one of those who need extra help. She tells her daughter, “There’s other people out there in the world.”