Only humans invent moralizing gods who monitor our behavior.

Naturally, things are more complicated - those groovy, pro-social effects of oxytocin apply to how we interact with in-group members.

Perhaps most excitingly, we are uncovering the brain basis of our behaviors - normal, abnormal and in-between. We are mapping a neurobiology of what makes us us.

It's probably even the case that if you stoked up some Buddhist monks with tons of testosterone, they'd become wildly competitive as to who can do the most acts of random kindness.

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

Give lab rats oxytocin and, according to that meme, they get better at talking about their feelings and sing like Joan Baez.

As long as experiencing your optimal level of good stress doesn't damage others, it's hard to objectively define where normal enjoyment of stimulation becomes adrenaline junkiehood.