Narcissistic personality disorder derives its name from the Greek God Narcissus, who was so enamored with gazing at his own image in a pool of water, that he fell in and drowned.

Do you ever wonder if he was admiring a specifically dazzling feature?

According to a new study, narcissists have “distinctive eyebrows.”

People with this mental health condition have an inflated sense of their own importance and appearance, seek admirable attention, and may lack the ability to empathize with others. New research from the University of Toronto, published in the Journal of Personality, suggests that narcissists also share a physical characteristic.

The Toronto research team conducted an experiment with approximately 40 undergraduate students. They photographed each with a neutral expression, then the students completed the Narcissistic Personality Inventory test to gauge the strength of narcissistic traits. The research team showed the photographs to the participants and asked them to speculate how narcissistic each person was based on their appearance.

Initial results showed participants found eyebrow thickness and a high density of hair were accurate indications of narcissism. The study went further and swapped narcissists’ and non-narcissists’ eyebrows between faces, and got the same outcome.

The team concluded that “distinctive eyebrows reveal narcissists’ personality to others,” but it’s unclear why others view eyebrows as a narcissistic indicator. Researchers theorize eyebrows play a role in body language, which humans are especially adept at perceiving. The phenomenon could also be explained by good old-fashioned grooming habits. Perhaps narcissists, ever seeking adoring attention, bust out the tweezers more often than others.