Looking smarter isn’t just about slapping on a pair of nerd glasses. To give off a brainy vibe, you may want to adjust your facial expression. 

A new study from University of St. Andrews psychologists finds that facial cues can influence whether or not people perceive you as intelligent. If your face suggests that you’re alert and slightly happy, people are more likely to perceive you as intelligent, the researchers found across four experiments. 

The researchers showed more than 500 participants images of 100 Caucasian adults between the ages of 18 and 33 and 90 kids between 5 and 17 to see how cues about mood and tiredness affect how intelligent people look to others. Some of the photos were of neutral faces, and others were manipulated to change the curve of the subject’s mouth and how open their eyelids were. 

Obviously, the way your face looks and what you’ve got going on in your brain have little to do with each other, but somehow, we humans see fit to equate them anyway. We assume beautiful people are more intelligent. Glasses, too, can make people think you’re intelligent

And even when controlling for the effects of attractiveness, facial expression has a “pronounced influence on perceptions of intelligence,” the researchers found. People thought both children and adults looked more intelligent when their eyes were more open and their mouths curved slightly up in a subtle smile. 

Especially when talking about children, these findings could have a major impact. Kids who are tired (or less than delighted) at school might be perceived as less intelligent by their teachers. The teachers' corresponding lower expectations could potentially have an impact on the kids' school lives and academic performance. It also just shows that there are even more unconscious biases we incorporate when judging other people than we realized.

But if you’re trying to look more intelligent—say, in a job interview—you may want to open your eyes wide and smile. 

[h/t Independent]