What happened in the milliseconds before a behavior to cause it? That's in the neurobiological realm.

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.

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.

To out-group-members, oxytocin makes you crappier - less cooperative and more preemptively aggressive. It's not the luv hormone. It's the in-group parochialism/xenophobia hormone.

But often, it's easier to resist temptation with distraction, or to be so inculcated in doing the right thing that it's automatic, outside the frontal cortex's portfolio - Then it isn't the harder thing, it's the only thing you can do.

If you live in a baboon troop in the Serengeti, you only have to work three hours a day for your calories, and predators don't mess with you much. What that means is you've got nine hours of free time every day to devote to generating psychological stress toward other animals in your troop. So the baboon is a wonderful model for living well enough and long enough to pay the price for all the social-stressor nonsense that they create for each other. They're just like us: They're not getting done in by predators and famines, they're getting done in by each other.

What does the frontal cortex do? Gratification postponement, executive function, long-term planning, and impulse control. Basically, it makes you do the harder thing.