It's not mere extremism that makes folks at the fringes so troubling; it's extremism wedded to false beliefs. Humans have long been dupes, easily gulled by rumors and flat-out lies.

Everybody loves to spend money at least some of the time - because everybody loves the stuff you can buy with it. The key to the pleasure level of any transaction is the balance between the pain of the payment and the reward of the purchased object.

The mind of the polyglot is a very particular thing, and scientists are only beginning to look closely at how acquiring a second language influences learning, behavior and the very structure of the brain itself.

If you're an older sibling and you have a younger sibling who needs mentoring or is afraid of the dark, you develop nurturing and empathic skills that you wouldn't otherwise have.

Since narcissism is fueled by a greater need to be admired than to be liked, psychologists might use that fact as a therapeutic lever - stressing to patients that being known as a narcissist will actually cause them to lose the respect and social status they crave.

Psychopaths know the technical difference between right and wrong - which is one of the reasons their insanity pleas in criminal cases so rarely succeed; they just fail to act on that knowledge.

When we're awake, cortisol can fragment memories - one reason eyewitness crime scene accounts are so unreliable. But at night that very fragmentation allows creative recombinations of ideas.