AND WE EVOLVED LONG ARMS SO WE COULD GIVE EVERYBODY BIG HUGS

New Hypothesis Says Allure of Human Eyes Has Evolutionary Advantage (Ker Than, Fox News, November 8th, 2006)

Humans are also the only primates for whom the outline of the eye and the position of the iris are clearly visible. In addition, our eyes are more horizontally elongated and disproportionately large for our body size compared to most apes. Gorillas, for example, have massive bodies but relatively small eyes.

The cooperative eye hypothesis explains these differences as traits that evolved to help facilitate communication and cooperation between members of a social group. As one important example, human mothers and infants are heavily reliant on eye contact during their interactions. One study found that human infants look at the face and eyes of their caregiver twice as long on average compared with other apes.

Other ideas have also been proposed to explain why humans have such visible eyes. For example, white sclera might signal good health and therefore help signal to others our potential as a mate.

Or, as one other recent study suggested, visible eyes might be important for promoting cooperative and altruistic behavior in individuals that benefit the group. The study, conducted by Haley and Daniel Fessler, also at UCLA, found that people were more generous and donated more money if they felt they were being watched——even if the watchful eyes were just drawings resembling eyes on a computer screen.

Wouldn’t it be something to hear a modern evolutionary biologist suggest humans evolved superior eyes in order to better stalk one another and aim weapons?