Causes of Introversion

Scientists don't know for sure if there's a cause for introversion or extroversion. What they do know is the brains of the two personality types work a little differently from each other. Researchers have found that introverts have a higher blood flow to their frontal lobes than extroverts do. This part of the brain helps you remember things, solve problems, and plan ahead.

Introvert brains also react differently to dopamine than extrovert brains do. That's a chemical that turns on the reward- and pleasure-seeking part of your brain. Introverts and extroverts have the same amount of chemicals, but extrovert brains get an excited buzz from their reward center. Introverts, on the other hand, tend to just feel run down by it.