Why you are mesmerized by people you've heard bad things about

When you hear nasty gossip about somebody, it changes the way your brain responds to that person's face. A new study reveals that, given a choice, people will stare longer at the faces of people they've heard bad things about.

A group of psychologists and medical imaging researchers wanted to know whether gossip does, in fact, have a scientifically measurable impact on our perceptions of other people. And what they found won't be surprising to anybody who has found themselves weirdly fascinated by pictures of tarnished celebs and accused killers.

Almost as intriguing as the study results themselves is the way the team of researchers set up their study. First, they showed study participants pictures of "neutral" faces - people who were ordinary-looking strangers to the viewers. Some of these faces were paired with phrases that contained what the scientists called "negative social information," such as "She is a cheater," or "She threw a chair at somebody." Others faces were paired with neutral or positive information.

Then the researchers showed the participants these same pictures in a "binocular rivalry" test. In this test, they would show a different picture to each of the participant's eyes. When you see two different images in each eye, your brain resolves this "rivalry" by suppressing one image in favor of the other, usually alternating back and forth. But how does your brain decide which image to favor over the other? It turns out that one deciding factor can be negative gossip.

Using neuroimaging, the scientists were able to measure which image the person's brain was focused on. People who saw a neutral face in one eye, and the face of one of the "liars" or "cheaters" in the other, always wound up watching the lying cheater for much longer. The decision wasn't a conscious one - the participants' brains were active in multiple regions, leading the participants to perceive the subjects of gossip more easily.

Previous studies have shown that people remember negative information better, so the scientists corrected for that possibility in a second series of tests. Even when memorizing negative information about the faces was no longer a factor, however, people still ogled those bad faces longer than anything else.

The scientists suggest that this built-in fascination for people we've heard bad things about could offer an evolutionary advantage. They wrote this week in the journal Science:

It is easy to imagine that this preferential selection for perceiving bad people might protect us from liars and cheaters by allowing to us to view them for longer and explicitly gather more information about their behavior.

Of course the problem is that this desire to gawk at gossip victims is inspired only by hearsay about their behavior. There's no guarantee that these really are "bad people." So a truly devious criminal would exploit this weakness in human neurology to their advantage by spreading negative gossip. While our attention was trained on all those alluringly awful people we'd heard such terrible things about, the true criminal would be picking our pockets.

Read the full scientific paper via Science