Almost by definition, a narcissist won’t recognise themselves as such.

After all, someone who has “excessive interest in or admiration of themselves” is unlikely to concede that less-than-flattering description.

But a new study has found an unexpected physical symptom of the trait.

According to researchers, narcissists give themselves away by blushing when they’re on the receiving end of only modest praise.

For the paper published by the journal Psychophysiology (via PsyPost) children aged between seven and 12 were given a Childhood Narcissism Scale survey to complete before being asked to sing a song.

They were then told one of three phrases: “You sang incredibly well” (inflated praise), “You sang well” (non inflated praise), or “I heard you sing a song” (neutral).

Volunteers who scored higher on the narcissism scale were significantly more likely to blush at non inflated praise compared to those who scored lower on the scale.

Additionally, those with stronger indicators of narcissism blushed far less at inflated praise.

Researchers speculated that the blushing signified the child’s dismay that the faint praise did not live up to their own vision of themselves and their talents.

“When narcissistic children receive modest praise, they may detect a discrepancy, and worry that others do not see them as positively as they see themselves,” says co-author Eddie Brummelman, of the University of Amsterdam. 

“They may blush as they feel exposed and believe they lost esteem from others.

“Together, these findings suggest that when narcissistic children don’t get the praise they think they deserve, they feel depreciated — a feeling that is revealed only by a blush.”

So, there you have it: if you want to be able to tell whether someone’s in love with his or herself, heap them with modest praise and look out for the blush. 

Of course, they may just be happy to hear your positive feedback, too. In which case, be alert to other signs: me-talk and rule shirking are dead giveaways.

Images: Getty