Our Brains Judge Faces Without Even Seeing Them

You know those gut feelings you get about a person the first time you meet them? Well, turns out that feeling doesn't come from your gut (duh), it comes from your brain. A new study from a team of researchers at Dartmouth and New York University found that our brains make instant judgements on faces, before we even consciously "see" them.

The team — which included Dartmouth's Jonathan Freeman and NYU's Eric Hehman and Ryan Stolier — studied the brain's amygdala, the region of that is responsible for judging human behavior, such as trustworthiness. The trio watched subjects' brains as they were shown a series of faces. The faces were created based on previous studies, that showed how people perceive someone's trustworthiness. Each was ranked on a trustworthiness scale that included low, neutral, and high. Some of the images shown to participants were of real people, some were computer generated.

First Impressions Are Instant

Research shows the brain evaluates a person’s trustworthiness before we’re even consciously aware of their face.

The subjects were shown the faces while attached to the brain scanner. Each face though, was only available for a fraction of a second. The quick exposure was couple with something called "backward masking," which is thought to confuse the brain and hinder its ability to comprehend images. Essentially, backward masking is showing a person a completely irrelevant image immediately after the relevant image.

The Role of the Amygdala

The amygdala tracks subtle facial cues, like eyebrow position and cheekbone structure, to form rapid judgments of trustworthiness.

When the tests were completed, the researchers found that the brain's amygdala was firing on all cylinders, even though it wasn't actually registering the faces. "Specific regions inside the amygdala exhibited activity tracking how untrustworthy a face appeared, and other regions inside the amygdala exhibited activity tracking the overall strength of the trustworthiness signal (whether untrustworthy or trustworthy) — even though subjects could not consciously see any of the faces," reported International Business Times.

Backward Masking Explained

Backward masking shows an irrelevant image immediately after the target image, preventing conscious recognition while the brain still reacts.

"Our findings suggest that the brain automatically responds to a face's trustworthiness before it is even consciously perceived," Freeman told Science Daily. "The results are consistent with an extensive body of research suggesting that we form spontaneous judgments of other people that can be largely outside awareness."

This is pretty crazy. Think about it from the perspective (no pun intended) of someone who has a face that just seems "untrustworthy." This study shows that they almost have no hope of avoiding this first impression. In the report, the team wrote that "Higher inner eyebrows and pronounced cheekbones are seen as trustworthy and lower inner eyebrows and shallower cheekbones are seen as untrustworthy." So basically, if you've got big eyebrows, might want to see about getting them thinned out. Or just have everyone think you're a shady dude for the rest of your life.

[Image via Flickr - Helmuts Guigo]