When you pose for a photo, toward which side do you naturally turn? If you turn to your right, you're in good company: most portraits throughout art history—and over 90 percent of depictions of Jesus on the cross—show the subject turning to his right, exposing more of the left side of the face.
Why? One answer could be that we tend to find the left sides of faces more attractive. That may have something to do with our neurology: the right brain, which controls the left side of the body, deals more with emotions. So the left half of faces are often more expressive.
In the video above, science writer Sam Kean, author of the upcoming book The Tale of the Dueling Neurosurgeons, explains the scientific origins of this phenomenon—and why you might even see this bias in your high school yearbook.