Trump thinks a mustache disqualifies you from office. So do a lot of Americans.

In our study, Peter Loewen and I asked Canadian undergraduates to rate official photos of incumbent politicians from Belgium and Israel. After briefly seeing a pair of photos, each student was asked to tell us which of the two had more of one of these three traits: dominance, trustworthiness and intelligence. This was repeated multiple times per student with different pairs of photos.

After collecting thousands of such pairwise comparisons, we computed overall impression scores on the three traits. And for both Belgian and Israeli politicians, mustached politicians were consistently and substantially evaluated as less trustworthy and less intelligent.

Mustaches weren’t the only superficial feature that changed how someone was evaluated. Glasses-wearing politicians were more likely to be judged as intelligent — but also as being less dominant. And while politicians who smile in photos score points on trustworthiness, they lose on intelligence. Both women and men were deemed less dominant and less intelligent when smiling. But smiling men were deemed more trustworthy, while women politicians were seen as less so.