As aforementioned, the introvert-extrovert scale is based on things like sociability and where you get your energy. On one end of the spectrum, introverts prefer quiet, reflective alone time, while extroverts prefer engaging with others, expressing themselves, and directing their focus outward.
Introverts also feel drained after spending time with people (especially large groups), whereas this is where extroverts thrive, and they’ll feel drained after too much alone time.
Research has also pointed to explanations in the brain for why some people are more introverted versus extroverted. Namely, one study1 found thicker regions in the prefrontal cortex of introverts compared to extroverts—the part of the brain that deals with things like planning and decision making, which could explain why introverts tend to be more reserved, while extroverts tend to be more impulsive.
“Of all the different personality traits, introversion and extroversion are one of the ones that are most strongly hereditary,” Page says, adding that environmental factors, such as how you were raised, will also come into play.
Our DNA also determines the degree to which we can be flexible in these traits, he says. “Introversion and extroversion is really connected to a whole bunch of issues around our neurotransmitters, and the most important one is dopamine,” he says.
Dopamine fuels our reward center in the brain, and Page explains that extroverts tend to appreciate or be motivated by those dopamine hits. “But introverts,” he notes, “their brains are less driven by that need for dopamine and that excitement over dopamine.”
And this phenomena has been backed up by studies, with research2 showing that extroverts have a stronger reaction and dopamine response to rewards than introverts, which both highlights that extroverts tend to seek more dopamine hits, and also reaffirms the aforementioned point about impulsivity.
As you might imagine, where you fall on the spectrum can manifest into many different areas of your life, from how you approach friendships and dating, to how you best get work done, to how you prefer to spend your time.
If you’re still not sure whether you’re an introvert or extrovert, here’s a quiz to find out.