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Introverts vs. Extroverts: How your brain works?

This article is written by a student writer from the Her Campus at U Toronto chapter.

Being an introvert or extrovert is more than just about the personality you’ve cultivated over the years.  Research shows that personality differences of this kind actually have a lot to do with operational differences in the brains of both kinds of people.

These differences are said to account, at least partially, as to why some people are more introspective while others are more social and prone to risk-taking.

Introvert vs. Extrovert

Being an introvert doesn’t necessarily mean you’re a hermit who hasn’t made contact with the world for the better part of a year, nor does it mean that you have a desk job that requires no social skills because you hate talking to people. The introvert with no social skills is usually just a caricature.

Being shy is also not a requirement for being an introvert.

All it means is that eventually, talking to people becomes more taxing, and you do need time by yourself because otherwise, you’d become overstimulated, according to the famous psychologist Carl Jung.

In this way, reading a book at home with a cup of hot cocoa in winter can seem more appealing than going out partying with your friends. Or maybe, instead of going out to party, you’d prefer to have a small gathering with close friends, so that there aren’t too many people to feel overstimulated around.

This means that you can be a social introvert, but you simply need time to ‘recharge’ yourself every once in a while, which requires you to take some time off and enjoy some alone time. For extroverts, the opposite applies. Being alone becomes draining, and you gather energy from social interaction instead.

The Ambivert

Carl Jung says that no one is truly all introverted or extroverted, but that we all exhibit traits of both. However, we tend to exhibit more traits of one than the other, which leads to labeling ourselves as an ‘introvert’ or an ‘extrovert’.  But in reality, it’s a spectrum.

What about those who have a balance of introverted and extroverted personality traits? Well, you’re called an ambivert.

Rather than enjoying partying all night long, or enjoying being by yourself totally with just your couch and a remote control, ambiverts are generally the people who hang out with friends, yet aren’t the last one partying, and will head home to enjoy a one-party movie night. Equal balance, all depending on the situation. 

But this can be challenging because an ambivert doesn’t generally know at what time social interaction or solitude overtaxes and makes them restless. This causes a fundamental difference in one person’s personality to the next, especially considering you can be an introvert, extrovert, or an ambivert who leans one way or the other depending on the situation you’re placed in. 

However, it’s not all environmental factors that drive your personality to be this way. It’s genetics and how your brain is wired to function that determine the degree to which you are likely to be introverted or extroverted.

Structural Brain Differences

In 1999, there was a study done where scientists attempted to find differences in the brains of introverted and extroverted people. They did this by carefully measuring the cerebral blood flow in both groups of people and compared the differences using a PET scan. Both introverted and extroverted people had differences in specific regions of the brain that had an increased blood flow. For introverts, these regions were the frontal lobes and anterior thalamus, areas known for memory, making plans, and problem-solving. For extroverts, blood flow was increased in the anterior cingulate gyrus, the temporal lobes and the posterior thalamus. 

The functions of these regions of the brain have to do with understanding the sensory data of your surroundings. Thus, for introverts, the brain is more focused on self-reflection, which explains why they enjoy quiet activities. Whereas, for extroverts, brain function is focused on what’s around you, which explains why they seek out social activity. Furthermore, introverts also have more brain activity in regions associated with learning, motor control, and self-restraint, which explains why they take part in less risky activities.

Boredom and Mental Stimulation

One theory suggested by the psychologist Hans Eysenck in the 1960s was that extroverts are generally more bored than introverts are.

In other words, their brains have less of what’s called cortical arousal, indicating that their brain is less active during passive activities.  Different activities can change how interested you are; for example, going to the bar with a group of friends would make me interested, while a monotonous, three hour lecture would increase my boredom instead.

Extroverts work harder to get themselves to a point where their brain is aroused in order to be less bored and be content – at a level that introverts just have naturally from quieter activities. Introverts have a high cortical arousal naturally, which means that a little bit more and they’ll become overstimulated right away. Therefore, loud, busy environments aren’t suitable for them.This theory is supported by how introverts and extroverts differ in processing rewards.

Processing Rewards

Introverts and extroverts process rewards very differently through the use of dopamine.

If there’s one scientific term you’ve ever heard in your life, it’s bound to be Dopamine. Over the years, it’s been associated with the enjoyment we get from indulging in chocolate and other good stuff we can’t get enough of, but perhaps should. But, in the scientific world, it is known as a chemical that our brain produces when we experience something good. That good feeling we get from something we enjoy is dopamine, and causes us to seek out that activity more to get that feeling again; hence, our addiction to chocolate, for example.

In 2005, there was a study done where people filled out personality profiles, indicating whether they considered themselves more introverted or extroverted, and then had their brains scanned while performing tasks to do with gambling. Those who were more extroverted received more of a response in the amygdala and nucleus accumbens parts of the brain when their gambles were a success.The amygdala is the part of the brain known for emotional processing, while the nucleus accumbens is a part of the brain involved in processing rewards and is involved in the dopamine system.

Extroverts are more sensitive to surprise rewards. They react a lot more if what they gamble pays off and in a sense, find it addictive and mentally stimulating. It’s a sort of thrill-seeking behaviour that increases their cortical arousal. This means that they’d be more likely to take risks socially and enjoy adventurous activities. It also explains why extroverts are social butterflies; it makes them feel good because of their reward circuitry. 

Individuals in this experiment who had a gene known to increase the potency of dopamine also enjoyed it more when their gambles paid off. That means dopamine and how it affects us is key to some of our personality differences.

Nature vs. Nurture?

What this shows is that people are the way they are because of a certain way their brain functions. Of course personal habits and personalities play a role in it, but some of the keys to our personality differences lie outside environmental causes. Our minds are all constructed very differently.

Enjoying the company of people all the time in loud environments or enjoying it only sometimes within smaller groups doesn’t just have to do with people not willing to get out of their comfort zones. Understanding that a lot of it has to do with differences in how our brains process and respond to our surroundings may help us appreciate the personality differences between us more. After all, the world would be a very dull place if it were composed of the same people. 

 

Image Sources

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Jina Aryaan is one of the Co-Editors-in-Chief of Her Campus UToronto. She is a fourth year student pursuing a major in Sociology, and a double minor in French and Latin American Studies at the University of Toronto. She has been working with Her Campus since her first year of University, and she is also highly involved on campus through various other leadership positions. When she's not busy studying, you can catch her running around campus to get to her next class or meeting. When she has some spare time, she's likely busy writing, discussing politics, or spending quality time with friends and family.