Do you know anyone who constantly looks like their in a pissed off mood? Rarely smiling? They almost look inapproachable. These people are victims of RBF or better known as "Resting Bitch Face". Think of actress, Kristen Stewart.

The Washington Post reports that scientists have discovered the reason behind RBF. They used some type of fancy-schmancy face reader that detects and interprets small cues about people's emotions, and ran more than 10,000 images of human faces.

It was found that people with RBF show the same subtle facial signs including one side of the lip pulled back slightly (not a smile) and their eyes are slightly squinted and tight.

The cues are understated, yet the machine detects and interprets them the same way our human brains do..."

Both the machine, and our brains, interpret these signs as contempt making us think that the person is judging us.

And if you thought that RBF was only in females, think again. The FaceReader found that men and women are equals when it comes RBF. *ahem* Kanye West

So RBF isn’t necessarily something that occurs more in women, but we’re more attuned to notice it in women because women have more pressure on them to be happy and smiley and to get along with others.”

Pascal Le Segretain/Getty Images

If you really want to know if you have RBF you can submit a picture of yourself but it has to be of your most "neutral" facial expressions. You can email it to