Almost always, genes are about potentials and vulnerabilities rather than about determinism.

The less it is possible that something can be, the more it must be.

The fascinating thing about our best and worst behaviors isn't the behavior itself - the brain tells the muscles to do something or other - big deal. It's the meaning of the behavior.

The problem isn't testosterone and aggression; it's how often we reward aggression. And we do: We give medals to masters of the "right" kinds of aggression. We preferentially mate with them. We select them as our leaders.

We live well enough to have the luxury to get ourselves sick with purely social, psychological stress.

Finish this lecture, go outside, and unexpectedly get gored by an elephant, and you are going to secrete glucocorticoids. There's no way out of it. You cannot psychologically reframe your experience and decide you did not like the shirt, here's an excuse to throw it out - that sort of thing.

The regulation of genes is often more interesting than the genes themselves, and it's the environment that regulates genes.