On a primal level, you are rewarded with dopamine when you meet a basic need, like eating or procreating. However, your reward system also picks up on other tasks that you enjoy.
For example, you may like football, so anything related to football (watching, playing, discussing) will trigger a release of dopamine. It’s the same thing when you are nice to someone.
Humans are social creatures and are conditioned from a young age to be kind to other people. Your brain releases dopamine when you’re nice to another person because you know you did a good deed and you enjoyed it.
our brain gives you a smiley face sticker, dopamine, as a reward and incentive to continue good behaviors.