Since the RBF meme took over the Internet in 2013, fueled by a viral mock-PSA about "Bitchy Resting Face," legions of people have identified the dreaded phenomenon in celebrity listicles, in their own social circles, even in the mirror.

So Jason Rogers and Abbe Macbeth, behavioral researchers with international research and innovation firm Noldus Information Technology, decided to investigate: Why are some faces seen as truly expressionless, but others are inexplicably off-putting? What, exactly, makes us register a seemingly neutral expression as RBF?

AD

AD

"We wanted this to be fun and kind of tongue-in-cheek, but also to have legitimate scientific data backing it up," Macbeth said.

The researchers enlisted Noldus's FaceReader, a sophisticated tool engineered to identify specific expressions based on a catalogue of more than 10,000 images of human faces. The software, which can examine faces through a live camera, a photograph or a video clip, maps 500 points on the human face, then analyzes the image and assigns an expression based on eight basic human emotions: happiness, sadness, anger, fear, surprise, disgust, contempt, and "neutral."

To establish a baseline, Rogers and Macbeth first had FaceReader assess a series of genuinely expressionless faces. Those expressions registered about 97 percent neutrality, Macbeth said; the remaining three percent included "little blips of emotion" — a touch of sadness here, a hint of surprise there, but nothing significant.

Then they plugged in photos of RBF all-stars Kanye West, Kristen Stewart and Queen Elizabeth. Suddenly, the level of emotion detected by the software doubled to six percent.

AD

AD

One particular emotion was responsible for the jump: "The big change in percentage came from 'contempt,'" Macbeth said.

And how exactly does a piece of software measure contempt in a face?

It's in subtle signals, like "one side of the lip pulled back slightly, the eyes squinting a little," Rogers explained.

Or: "It's kind of a tightening around the eyes, and a little bit of raising of the corners of the lips — but not into a smile," Macbeth suggested.

The cues are understated, yet the machine detects and interprets them the same way our human brains do, she said. "Something in the neutral expression of the face is relaying contempt, both to the software and to us."

But there was one big difference, she added. FaceReader, being a piece of software and therefore immune to gender bias, proved to be the great equalizer: It detected RBF in male and female faces in equal measure. Which means that the idea of RBF as a predominantly female phenomenon has little to do with facial physiology and more to do with social norms.

Consider actress Anna Kendrick, who has publicly bemoaned the effect of RBF on her life.

AD

AD

"When she was younger, directors would say, 'Why don't you smile more, you need to smile more, you don't seem like you're very happy,'" Macbeth said. "That's something that's expected from women far more than it's expected from men, and there's a lot of anecdotal articles and scientific literature on that. 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."