THURSDAY, May 19 (HealthDay News) -- Gossip can be malicious and mean, but it also may serve a protective purpose, forcing the brain to focus on people who might be threatening, a new study suggests.

Volunteers shown pictures of otherwise unmemorable faces lingered longer over pictures of people about whom they'd heard unflattering information, researchers say.

When shown images in which they had been told something positive or neutral about the person, the volunteers spent less time looking at them. That also was true for faces they observed for the first time without knowing anything about them.

From a practical standpoint, it suggests that negative gossip helps people better predict who might hurt them, say researchers from Northeastern University in Boston.

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

Gossip, whether "delicious or destructive," serves a function, according to the study, to be published online May 19 by the journal Science. In lieu of direct experience, social tittle-tattle allows people to learn about others across a very wide group, the team say. That, in turn, gives people cues on who to befriend (or not) without having to actually have to spend lots of time with them first.

The study consisted of two experiments designed around a visual phenomenon called "binocular rivalry," in which one image is shown to one eye and a different image is simultaneously displayed to the other eye. Rather than seeing two images superimposed, one is seen for a few moments, then it morphs into the other, then it reverts to the first, and so forth.

In the first experiment, 66 participants were shown bland faces that were paired four times with a description of social behavior -- negative, positive or neutral that the person depicted had supposedly done. These included statements such as "helped an elderly woman with groceries" or "threw a chair at his classmate." The second experiment used 51 volunteers.

Participants pressed a keyboard key for the duration that they consciously experienced seeing a particular face, or one unrelated image (in this case, a house).

Participants in both experiments lingered on the faces longer than the house. But the key finding, according to the authors, was that they lingered on faces that had been linked to negative social behaviors longer than those linked to either positive or neutral information.

Conventional wisdom says that what you see affects how you feel, but the study suggests the reverse also is true.

"I think it is interesting and a little surprising that four pairings of descriptions of negative social behavior was sufficient to induce a negative response about the previously neutral face," said H. Elliott Albers, director of the Center for Behavioral Neuroscience at Georgia State University. "It would have been interesting to see if the effect also occurred if the neutral stimulus was not a face but some other non-social stimulus like a geometric shape. Nevertheless, the possibility that gossip can actually modulate a visual response is intriguing."

The findings have potential implications for mental health professionals dealing with patients who, for example, have experienced trauma, anxiety and depression, said lead researcher Lisa Barrett, professor of psychology at Northeastern.

More information

For more information about binocular rivalry, head to the Harvard University Vision Sciences Laboratory.