Sometime in July, we met up at a local playground with friends whose children are the same age as our 7- and 4-year-olds. Everyone was masked, and it was basically the first time we had socialized with people we weren’t related to since March. For the first 20 minutes of the play date, the children completely ignored each other. They’d make brief eye contact and then go careening off to different parts of the park.

As I watched the children appear to flee from social connection, I broke into a light sweat: Had they forgotten how to relate to other kids while under quarantine?

When we asked NYT Parenting readers for their most pressing concerns, some version of the above was the most frequently asked question: How will masks, social distancing and lack of interaction with other children affect their kid’s social and emotional development? For example, reader Ariel Wittenberg, mom to a 7-month-old in Arlington, Va., wrote, “The thing that keeps me up at night is what it means that my daughter essentially has no idea other babies exist. Is she going to have problems socializing in the future?”......