It isn’t totally surprising that Trump seems to think his IQ is exceptional. If asked, most people would say they are smarter than the average person. (They would also likely say they’re more competent, kinder, more honest, and more responsible.) This is a well-studied phenomenon in psychology known as the “better-than-average effect” or “self-enhancement.”

Even so, people might be reluctant to publicize their sense of superiority, because such boasts tend to be poorly received. One study found that while bragging about your own good qualities didn’t necessarily make people dislike you, bragging about yourself in relation to others did. For example, saying “I am a good student” probably wouldn’t bother anybody, but saying “I’m a better student than others” would. Bragging about your better-than-average intelligence, then, would likely make other people think you’re insulting them—and make them feel aggressive toward you as a result.

“We see this consistently, that the claim, at least in this culture, of being above average is just frowned upon,” says Joachim Krueger, a professor of psychology at Brown University who has studied bragging. “There are also conversational norms.” There’s an expectation that your good qualities will reveal themselves over time, without you announcing them.

So if bragging about your intelligence can alienate people, and make you look like a loser (at least to Stephen Hawking), why risk it?

It feels great, for one thing. People love to talk about themselves—to the point that in one study, they turned down money for the opportunity to answer questions about themselves. And the same study found that self-disclosure appears to activate brain regions associated with reward.

They may also miscalculate how others will react to their boasts. One study found that people often self-promote because they’re trying to make a good impression on others. But they tend to overestimate how much their self-promotion will make other people feel happy for them and proud of them, and underestimate how annoying people will find it.

Krueger coauthored a study in 2016 that found bragging about your superiority comes with a tradeoff. It will make people see you as more competent, but less moral—unless the thing you are bragging about is provably false. Then it makes people see you as incompetent and immoral.

In a case like Trump’s brag about being smarter than Tillerson, where the validity of his claim is unknown, the research suggests people would err on the side of believing him.

“My personal opinion of the president’s claims about his own IQ is that he is making a gamble: brag and be thought of as competent (intelligent), and hope that nothing will ever surface that proves his claims wrong,” Patrick Heck, Krueger’s coauthor on the study, told me in an email.