But just because they believe it, doesn’t make it true, he said. Young millennials and members of the generation that follows may just be buying into a stereotype that is perpetuated by the news media, and for which scholars carry some blame.

“That narrative, in part, started with us,” Dr. Grubbs said. “Psychologists were the ones that talked about the narcissism epidemic to begin with.”

That idea began gaining traction about two decades ago as a few psychologists argued that historical data stretching back a generation showed that young adults had grown increasingly self-absorbed.

The news media picked up on the findings, but not on the pushback. Further research suggests that the claims may have been overblown, Dr. Grubbs said. But he and his colleagues weren’t interested in joining that back-and-forth, anyway. They wanted to focus on a part of the discussion that they felt had been otherwise ignored.

“There’s this huge debate in psychology and there has been for years,” he said. “But no one had taken the time just to basically say, ‘Well, how do these kids feel about that?’”