Horrified expression is a sure-fire attention getter, U.S. researchers said on Sunday, based on a study of how fast people process facial expressions.
They believe fearful facial expressions make a beeline to the alarm center of the brain known as the amygdala, cuing humans to potential threats.
Of emotional information, a horrified expression is an easy way to get others' attention because people recognize the expression faster than any other, .
The finding is based on a study of how fast people process facial expressions, namely, fearful, neutral and happy expressions.
The researchers think that a region of the brain called the amygdala, which has a primary role in processing emotional information, shortcuts the normal brain pathway for processing visual images and causes the fearful face to jump out more quickly.
"We think what is happening with fear is that this is a critical threat signal for us," said David Zald, associate professor of psychology at Vanderbilt University in Tennessee. "Fear tells you something is wrong and you need to pay attention."
Zald and his colleagues think the expression of the eyes in a fearful face holds the key to its quick recognition.
"Fearful eyes are a particular shape, where you get more of the whites of the eye showing," Zald said. "That may be the sort of simple feature that the amygdala can pick up on, because it's only getting a fairly crude representation."
The fast recognition of fear may be an evolutionary survival mechanism geared to direct attention to signals of potential threats in the environment.
Happy expressions were the slowest to be recognized according to the study, which also fits into the evolutionary explanation.
"What we believe is happening is that the happy faces signal safety," Zald said. "If something is safe, you don't have to pay attention to it."