When it comes to people, there are typically two types: introverts and extroverts. The former is a person who keeps to themselves and doesn't crave any more attention than they need, while the latter is a person who likes to be the center of attention and is often very loud to attract it.
Both personalities are light night and day in terms of behavior, but why do these two kinds of personalities exist, and which is better to be?
Studies into the brain find that introverts typically have thicker prefrontal cortexes in their brains, which can be associated with deeper thought and having to think things over. Extroverts, on the other hand, are more impulsive and lack these kinds of deep thought.
Conversely, introverts who over-think things tend to suffer more from anxiety and depression, while extroverts have a much stronger dopamine production in their brain from certain activities, tending to lead them to happier lifestyles.
In summary, there are probably evolutionary advantages in both types of minds, as each supports the other in their weakness. Genetics are believed to play a big role in both.