There's a sort of sibling moratorium when you're establishing yourself as an adult. So much of your energy has to be focused on other things like work and kids. But when people become more settled, siblings tend to regroup because now you're building a new extended family.

Members of royal families are born into a world of indulgence and entitlement, and the princelings who grow up that way may never have to develop the emotional musculature that will allow them to show self-restraint.

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.

When you're your parents' one shot at a genetic legacy, you may get to attend all the best schools, wear all the best clothes and eat all the best foods - at least relative to children in multiple-sibling households. But you also wind up with an overweening sense of your own importance.

I was born in the U.S., my wife was born in Mexico and emigrated here when she was in college, and my daughters were born in New York City. That makes them passport-carrying, natural-born, eligible-to-run-for-president Americans. But they're also Mexicans and they like that just fine.

A cockroach likely has no less brainpower than a butterfly, but we're quicker to deny it consciousness because it's a species we dislike.

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.