Photo-Illustration: Science of Us; Photo: Ty Wright/Getty Images

You remember one of the major political stories of 2011, even if you wish you couldn’t: That year was the height of the “birtherism” movement, loudly led by none other than Donald Trump. And so it was no surprise that at the White House Correspondents’ Dinner that year, Obama shot back at Trump, ridiculing the reality-TV star for his tacky taste in décor, among other things. Over the weekend, a piece in the New York Times made the argument that this incident may have helped spark Trump’s interest in a presidential bid, and that much of his campaign is at least partially motivated by a deep-seated need to be taken seriously.

This is, at first, hard to reconcile with the current understanding of Trump as a textbook narcissist, which is typically defined as a person who has outsize self-esteem. Why would someone with higher-than-usual self-esteem care if others didn’t take them seriously? The question happens to be a near-perfect example of a newer way scientists are conceptualizing narcissism. In contrast to narcissism as a sign of inflated self-regard, it may instead be quite the opposite: All their outward bragging and bluster may in fact be signs of a fragile sense of self-worth.

To scientists who study narcissism, this is considered a “contentious” new assertion. Much of the existing literature suggests that, though it may annoy those around them, narcissistic tendencies can often be a healthy thing for the individuals themselves. (Quick note: We’re talking here about narcissism as a personality trait, which is different from narcissistic personality disorder; the latter is considered a treatable mental illness, and is listed in the DSM.) After all, if you ask them, narcissists will tell you how happy they are, and how high their self-esteem is; they also tend to report less depression, anxiety, and loneliness than non-narcissists.

And yet most of these studies have one inherent flaw: the narcissists themselves. Of course narcissists would never tell you explicitly that they are quietly panicking about their self-worth. (Trump, after all, is the guy whose only note when presented with the cover art for his 1987 book The Art of the Deal was “Please make my name bigger.”) But in some fascinating new studies, the brains and bodies of narcissists betray them.

Consider, for example, one often-cited study conducted by a trio of scientists at the University of Pennsylvania, which found that narcissists show “hypersensitivity” when they’re excluded, the authors write in the journal Neuroscience. In an experiment, they asked their participants to play a game of “Cyberball,” a computer game that’s often used in this type of research. The rules of Cyberball are simple; it’s essentially a game of virtual hot potato. The study volunteers are told they’ll be playing the game with two other participants in the study, who are seated in another room — they’re actually, however, playing with the pre-programmed computer game itself. In round one, the virtual players pass around the ball equally. But as the second round progresses, the computer slowly starts to exclude the human player. By the end of the round, the study volunteer is left out of the game entirely.

The participants in this study played while an fMRI recorded images of their brain activity. Before playing, all the participants took a survey designed to measure their levels of narcissism, rating how much they agreed with statements like “If I ruled the world it would be a better place” or “The thought of ruling the world scares the hell out of me.” In the end, the results of the study showed that those who were more narcissistic were more wounded by the exclusion: The fMRI picked up increased activity in the narcissistic participants’ anterior insula, dorsal anterior cingulate cortex, and subgenual anterior cingulate cortex — together, these regions are sometimes called the “social pain network.”

And yet when the researchers asked the narcissists directly whether they’d been hurt by being excluded from the game, they denied it. But you don’t have to have state-of-the-art brain-scanning equipment to see that narcissists suffer over this type of insult. One study published last year found that when narcissists were insulted, they tended to react more aggressively than non-narcissists, choosing more frequently to blast the person who’d rejected them with a loud, unpleasant noise. For our purposes, remember Trump’s reaction to Marco Rubio’s “small hands” taunt? The man used part of his stage time at a surreal debate among the remaining Republican candidates earlier this month to assure voters that, actually, his penis is quite big:

“ I have to say this: He hit my hands. No one has ever hit my hands. Look at those hands, are those small hands?” Trump said, proudly displaying his stubby paws. “And he referred to my hands as if, if they’re small, something else may be small. I guarantee to you there’s no problem, I guarantee!”

Other studies have shown that narcissists tend to have a stronger physiological response to stressful events, such as public speaking. But even in everyday, non-stressful situations, narcissists tend to harbor higher levels of the “stress hormone” cortisol. (This happens to be especially true in men, at least one study has suggested.) As researchers in a 2010 paper on this subject wrote, narcissists’ “underlying physiological responses betray their supposed psychological robustness and social nonchalance.” In other words, they may appear confident on the outside, but “in reality, the trait is also associated with being socially needy and defensive.”

Last year, a study in neuroscience suggested that narcissists’ low-self-esteem issues may be explained by structural differences in their brains. Narcissists tend to have weaker connections between two important brain regions involved in self-esteem: the ventral striatum, which is associated with reward, and the medial prefrontal cortex, which is associated with your sense of self. People with high self-esteem have stronger connectivity between these two areas; in people with low self-esteem, on the other hand, that connectivity tends to be weaker. And narcissists, as it turns out, experience a “neural disconnect” here.

Taken together, the bluster associated with narcissism has caused some scientists to begin to argue that it can in fact be understood as “compensation” for narcissists’ weak sense of self-worth. “The exhibitionism and immodesty of narcissists may then be a regulatory strategy to compensate for this neural deficit,” wrote the authors of the connectivity study. Surely there is another tiny-hands-and-compensation joke in there somewhere, but I’ll leave that to the experts. Or to Rubio.