Importantly, rather than promoting aggression, testosterone promotes whatever is needed to maintain status when challenged.

...when doing science (or perhaps when doing anything at all in a society as judgmental as our own), be very careful and very certain before pronouncing something to be a norm - because at that instant, you have made it supremely difficult to ever again look objectively at an exception to that supposed norm.

Only humans invent moralizing gods who monitor our behavior.

The gigantic challenge is the magnitude of the individual differences in the optimal set point for "good stress." For one person, it's doing something risky with your bishop in a chess game; for someone else, it's becoming a mercenary in Yemen.

Stress is not a state of mind... it's measurable and dangerous, and humans can't seem to find their off-switch.

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

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