Mutual cooperation activates brain regions linked to reward, releasing a feel-good chemical cocktail of dopamine, endorphins, and endocannabinoids. Call it a cooperation high: It feels good to work with others toward a shared goal. Brain-imaging studies show that when you see the face of someone with whom you previously cooperated, it reactivates your reward system. From an evolutionary point of view, this is the neurobiological foundation of trust. It’s also a kind of anticipatory high.
