His study of Sarajevo siege survivors, for example, found that many had a super-heightened sense of spatial awareness — a skill for evading bullets or bombs that they carried with them throughout life. And mask wearing remains widespread in societies hit by the SARS and MERS epidemics, even for routine colds.

When the coronavirus outbreak is under control, aversion to strangers or large groups, and the threat of infection they could pose, might echo in our minds for years.

Mr. Bozovic, the Sarajevo survivor, recalled, as a metaphor for deeper changes, a street near his home that was often targeted by snipers. He avoided it during the war — and, to his surprise, well after.

“I don’t think I walked that street for months,” he said. “That lingers, that stays. And I’m sure it’s going to be the same now.”

While deeper shifts are difficult to predict, he added, one seemed obvious: “I think it will profoundly change how we interact physically with other people.”