The Matter of It All 

Grey and white has quite literally become the new black. Grey and white matter in the brain that is.

“You have to remember that everybody has differences in their brains,” school psychologist Dr. Courtney Alison said. “The brain is very complex. There are a bunch of studies that show that introverts tend to have larger and thicker gray matter in the prefrontal cortex, which is really your high order thinking, where you’re doing computations and that’s associated with abstract thought and decision making. Your gray matter in your brain is what’s used for processing and white matter is used for communicating between different parts of the brain. So this one study found that introverts have more grey matter so they’re more abstract thinking and processing. People identified as strongly extroverted had thinner grey matter in those areas, which hints introverts spend more of their neuroresources on thinking kind of deep thoughts.”

Though introversion and extroversion are based on a spectrum, there are more differences between each side of the brain than the pigment of the matter.

“In the right hemisphere, the amendola, connected to memory and emotional reaction, tends to be larger in extroverts than in introverts, as does the anterior cingulate cortex,” Alison said. “Now both of those are areas that are implicated in emotionality and memories. It is also involved in the reward system, empathy, impulse control and emotion. And the amendola is memory and emotional reaction. There are also differences in how introverted and extroverted brains respond to some neurotransmitters.”

Nature vs. Nurture

These differences are important but psychologists advise that like most other things extroversion and introversion are brain based, the
catch is that brain structure can’t fully determine which side of the spectrum a person will lean more towards. Other factors such as genetic make-up and personal experience contribute as well. But sometimes the line between these two factors begins to blur.

“Modern research shows that heredity plays a significant role in determining our personality characteristics,” AP Psychology
Teacher Amy McConnell said. “But experiences and situations will always influence our behaviors. I believe most people will measure toward being either one or the other and are naturally predisposed to be so, but I think day to day experiences will often times draw us out of our natural tendencies and we will behave in ways that may or may not be predictable. There are plenty of introverts that act
extroverted and vice versa.”

Defining Introverts and Extroverts
Introverts and extroverts are most commonly defined by where they draw their stimulus from. While extroverts look externally for stimulus, introverts look internally.

“An extrovert is a person who draws energy from being around other people,” Dr. Alison said. “It has to do with your baseline level of arousal. A person who is an extrovert has a low internal level of arousal, therefore they go out and look for more stimulation. Thats why extroverts feed off other people.Whereas a person who is an introvert has a naturally high internal level of arousal, so being around people adds more and makes large social situations overwhelming. One researcher labels introverts diminishers because in many situations they have to diminish the stimulation because they have a naturally hyperalert arousal level so they can avoid having to shut down due to being overwhelmed. [The researcher] labels extroverts augmenters because in a majority situations they need to increase their level of activity or stimulation in order to achieve sufficient wakefulness.”

Make It or Fake It

As introverts become more and more romanticized in the media and literature it is important to understand that each has it’s advantages, and can take on traits of the other. “An extrovert is probably gonna have an easier time socially,” Dr.Alison said. “If that’s your job or if you need that for your success you could grease wheels that way and understand social cues. There are advantages in that an introvert can focus, they’re probably in tune with their feelings, sitting there thinking a lot and processing makes them more empathetic. But on the other hand extroverts could have a lot of experiences with social natures and use that and be emphatic.”

It also often acknowledged that introverts have to fake extroversion in order to fit in, but in reality they have just adapted to the situation around them or developed enhanced their social skills. Once the issue of being one’s true self is addressed and resolved, I think feeling like you need to fake extroversion to “fit it” represents a very important misunderstanding about introverts. Introversion is not about being shy or in extreme cases having social anxiety or a social phobia. Introverts are not shy or fearful people, they simply have a preference and deep appreciation and need for solitude and “alone time.” Introverts will socialize and talk about topics of interest and can be highly skilled in fields such as public speaking, performance, and in social situations. But they will also be exhausted by the effort they put in to the interaction and will desire time to decompress and re energize with some time alone at the end of the day.Extroverts similarly are some times stereotyped as not capable of deep thought or reflection. Dr. Alison also acknowledged that a change from one side of the spectrum to the other is rare.

“Extroverts can sit quietly and read books and think deep thoughts and need a little alone time,” Alison said. “I guess change in personality is possible because when we’re doing diagnostic things, testing for personality disorders, we’re really not supposed to diagnose somebody with
a personality disorder until they’re 18, because the assumption is that their personality hasn’t fully developed. I do think that the older you get the chances of your personality changing becomes less likely, but I mean, you know things happen. It’s unlikely to have a complete transformation.