When I was in high school, the honor roll was dominated by beautiful young ladies. The homecoming queen and her princesses were always near the top of the list, as were many of the cheerleaders. Why was it that the prettiest girls in the school were also the smartest? Well, they weren't. Appearance, personality and the ability to fit in socially often gave these girls an advantage over equally able peers when it came to getting good grades. Likewise athletic, outgoing, middle-class guys tended to get better grades than their less socially-adept classmates. Because of hidden (and difficult to overcome)...