“…extroverts have a more active dopamine reward system than introverts. Dopamine is a neurotransmitter that helps control the brain’s pleasure and reward centers. Having a more active dopamine reward system means that extroverts get more energized and excited by the possibility of reward than introverts. So extroverts are more driven to strike up a conversation with a stranger or hang out at the bar until last call…” Click Why Socializing Drains Introverts More Than Extroverts | Psychology Today for the rest of the article.