At the root of the shy temperament is a deep fear of social judgment, one so severe it can sometimes be crippling. Introverted people don't worry unduly about whether they'll be found wanting, they just find too much socializing exhausting and would prefer either to be alone or in the company of a select few people.

Science has yet to isolate the Godiva Chocolate or Prada gene, but that doesn't mean your weakness for pricey swag isn't woven into your DNA. According to a new study of identical twins, it's less TV ads or Labor Day sales that make you buy the things you do than the tastes and temperaments that are already part of you at birth.

Narcissism, like the other personality disorders, is a condition that's known as ego-syntonic. In other words, the paranoid person really does believe that people are after him, and the narcissist really does believe that he or she is better than or more entitled than other people, and truly doesn't see why that's not the case.

Kids whose puberty begins too soon face not just psychological risks, but physical ones too, with an increased likelihood of cancer, as well as skeletal changes that could prevent them from attaining their full adult height.

Learning to speak was the most remarkable thing you ever did.

It's one of the worst-kept secrets of family life that all parents have a preferred son or daughter, and the rules for acknowledging it are the same everywhere: The favored kids recognize their status and keep quiet about it - the better to preserve the good thing they've got going and to keep their siblings off their back.

Certainly, people can get along without siblings. Single children do, and there are people who have irreparably estranged relationships with their siblings who live full and satisfying lives, but to have siblings and not make the most of that resource is squandering one of the greatest interpersonal resources you'll ever have.