Twenge and her colleagues have found that narcissism is on the rise in the United States, a conclusion based on large surveys in which people answer questions about their self-regard and expectations out of life. This work is not without controversy, but Twenge argues that the survey’s findings mesh with evidence of rising narcissism as found in other domains: people’s increased belief in their own uniqueness, the rise in plastic surgery (greater than what would be expected from affordability alone), individualistic language in books and song lyrics, increasing desire for fame, and even increasingly unique baby names.

To the extent that the general public is becoming more self-involved, politicians might be increasingly ego-driven, as well. But presidential races are their own breeding grounds for narcissism, above and beyond any cultural self-absorption. Round-the-clock media scrutiny and social media mudslinging likely dissuade the nonegotistical from even running, said Ashley Watts, a doctoral student at Emory University in Atlanta and an author of the 2013 study on presidential narcissism.

“I think presidents [now] are more susceptible to media and public scrutiny,” Watts told Live Science. “We’re maybe selecting out the kind of people who can’t handle that kind of scrutiny.”