To me, one of the most fascinating aspecsts of diversity work is nonverbal communication. How much is innate and species-wide? How much is learned and cultural? We know some specific gestures don't translate well: for example, the American "OK" sign, which is exceedingly rude in some places, as a friend of mine found out after she used it to thank a sweet little old Brazilian lady who had helped her find the right bus.
But the facial expressions that express the basic human emotions seem to be universal, according to research by Paul Ekman and others. And a very clever study of blind Olympic athletes suggests that full-body gestures of pride and shame may also be inborn. And like the facial expressions, we share many of them with our fellow primates.
Why these specific gestures? Here's a study that suggests that the spontaneous expression of fear may have a practical advantage...the better to see you with, my dear!