Our happy hour fact to amaze your drinking buddies with.

People who are shy or introverted process stimuli around them differently than their extroverted counterparts.

A team of American and Chinese researchers discovered that about 20 percent of humans have a personality trait known as sensory perception sensitivity (SPS). People with this trait take longer to process the information around them -- and do so more carefully. As a result of this extended rumination, those with SPS are slow to warm to new situations and often appear shy.

In a recent study, volunteers were shown two pictures with subtle differences. Not only did the participants with SPS spend more time trying to distinguish between the images, but brain scans revealed significantly greater activity in the part of their brains which analyzes visual stimuli.

Since SPS is present in many other species, scientists believe it has evolutionary benefits. They speculate that in times of danger, the ability to delay action and come to the most carefully thought-out conclusion is advantageous.

So if you ever embark upon a risky adventure, it's just as important to bring a shy person along as it is a compass or canteen. Don't worry, he won't say very much -- but try not to rush him when he's trying to get you out of a pickle.