It's great to have a buff frontal cortex to do that harder thing - for example, help a person in need rather buy some useless, shiny gee-gaw.

Some Poor grad student pressing on the flanks of a hamster and out comes a doctorate on the other side

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.

Brains distinguish between an Us and a Them in a fraction of a second. Subliminal processing of a Them activates the amygdala and insular cortex, brain regions that are all about fear, anxiety, aggression, and disgust.

The most important point of [Susan] Fiske's work is that it provides a taxonomy for our differing feelings about different Thems - sometimes fear, sometimes ridicule, sometimes contemptuous pity, sometimes savagery.

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.

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