Under my byline

Fear makes sense

Posted in Health by Rrishi on 22 June 2008

Our expressions tell an evolutionary story

Google recently created a whole new range of animated “rich emoticons” for users of its e-mail and online chat services. They’re really quite amusing, and (as their plainer cousins have done for years) they help give our staccato online conversations a measure of the emotional depth that our facial expressions allow us to convey while talking face to face.

Although facial expressions have obvious social utility, scientists have long wondered why they originally developed. Expressions don’t just help us communicate (which is already an evolutionary advantage) — they also change the way we sense the world.

Charles Darwin himself thought along these lines. If expressions are purely for communication, then why is it, he asked in 1872, that some expressions are identical across race and culture, even across species? After all, our other major means of communication, language, is not.

A team of scientists led by Joshua Susskind and Adam Anderson at the University of Toronto set out to investigate this mystery. After looking at thousands of portraits, they quickly figured out that the expressions for fear and disgust were at opposite ends of the spectrum.

In fear, the eyes open wide, the eyebrows rise, the nostrils dilate and the mouth opens slightly. In disgust, it is just the opposite: the face is scrunched up, the eyes scrunch, the nose wrinkles and the mouth is pursed. (Try it.)

In their simple experiment, volunteers were told to do certain tasks while mimicking these two extremes of expression, as well as a neutral, relaxed expression. They had to track a dot on a screen, look back and forth between two dots, and observe lights being turned on and off around their heads. While doing this, they wore a mask that measured the amount of air they were breathing, and sat in an MRI scanner that tracked the exact size of their nasal cavities.

It may come as no surprise then, but the researchers found that in fear, with eyes wide open, the visual range was widest, and the amount of air breathed greatest. In disgust, the opposite was true.

“These changes are consistent with the the idea that fear, for example, is a posture towards vigilance, and disgust a posture towards sensory rejection,” Susskind said. From an evolutionary perspective, when afraid, you must sense your environment best to watch for danger.

Next time you’re asked to “sit up and pay attention,” remember to look afraid.

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