Faces hold a special power for us, perhaps more so than art or objects. The beauty bias has a real influence upon us, something we should be mindful of when dealing with others.

In a way, pretty faces are rewarding. They make us more likely to think good thoughts. There are some underlying processes going on in the brain that prejudice us to respond to attractive people better even if we are not aware of it.

Studying attractiveness has a long history. Since the 1970s, psychologists have shown that attractive people get better jobs. Attractive people are preferentially hired and promoted.

This favoritism, while poorly understood, seems to be innate and cross-cultural. Studies suggest that even infants prefer pretty faces.

We're able to judge attractiveness with surprising speed and on the basis of very little information. It seems that pretty faces 'prime' our minds to make us more likely to associate the pretty face with a positive emotion.

There are no definite rules to what kind of face can be called beautiful, but we chose faces of extreme -- very ugly or very pretty.