You prefer to curl up and read a book by yourself over going to a flashy social event. You like the company of one close friend rather than a group of many rowdy people. Once more you prefer to stay on the safe side than take risks. Does this sound familiar? If so, then you are probably an introvert. You may already know this but what you may not be aware of is that there are physical differences in your brain that make you prefer quiet activities over those that are highly energized.
Carl Jung’s studies
It was Carl Jung who in the 1920s coined the terms introvert and extrovert. He did so to describe contrasting personality types and to explain why different people were energized in distinct ways. He hypothesized that extroverts gained their energy from their social interactions and eternal environments and tended to feel uncomfortable and anxious when they found themselves alone.
Introverts, on the other hand, Jung explained, are able to replenish their energy levels when they are in quiet environments. Unlike extroverts they find socializing and busy environments overstimulating and too demanding.
Dr. Laney clarifies in her book, The Hidden Gifts of the Introverted Childthat “introversion and extroversion are not black and white. No one is completely one way or another – we all must function at times on either side of the continuum”.
Introversion and extroversion are at the opposite ends of the same spectrum. Everybody moves up and down the spectrum depending on external and internal factors, however, a person tends to prefer one personality type over the other.
The Dopamine difference
A major difference between the brains of introverts and extroverts is the way they react to the neurotransmitter dopamine.
Dopamine is a chemical that is released in the brain. It gives a person their motivation to achieve external goals and receive external rewards. For example, dopamine may motivate an individual to earn more money, increase their circle of friends, attract a good looking partner or advance to a higher role at work. When dopamine is released all of us become more alert to our surroundings, more talkative and more motivated to undertake activities that may be perceived as risky.
Introverts and extroverts have equal amounts of dopamine in their brains, however, the difference between these two categories of people is the activity of the dopamine reward network. The dopamine reward network is more active and dynamic in the brains of extroverts as Scott Barry Kaufman, the Scientific Director of The Imagination Institute says. When an extrovert anticipates a social event, for example, they feel good and energized, whereas the introvert will feel overstimulated.
Acetylcholine and Introverts
Christine Fonseca writes in her book Quiet Kids: Help your introverted child succeed in an extroverted world that introverts prefer to rely on a different neurotransmitter called acetylcholine.
Acetylcholine is related to pleasure, just like dopamine, however acetylcholine makes a person feel good when they turn inward. It gives a person the skill to reflect and focus solely on an individual task for an extended period of time. As it is simpler to turn inwards when there is limited external stimulation, introverts opt for a calm environment.
Introverts prefer one side of the nervous system over the other
The nervous system is divided into two distinct parts: there is the sympathetic side which is related to the “fight, fright, or flight” response; and the parasympathetic side. The parasympathetic side allows us to rest and digest.
When the sympathetic side is stimulated the body prepares for action; adrenaline is released, glucose energizes the muscles and the amount of oxygen in the body increases. The thinking mechanisms in the brain are put on hold. Dopamine increases alertness in the rear of the brain.
When the parasympathetic side of the brain is in gear; muscles relax, energy is stored and food is metabolized. Blood flow and alertness in the front of the brain increase as acetylcholine is released.
Although extroverts and introverts use both sides of the nervous system, various times introverts tend to prefer to use the parasympathetic side. This allows introverts to be calm and to act in a slow and measured way.
Why introverts tend to overthink
When information from the external world is received by an extroverts brain it travels via a short pathway that goes through the areas of the brain where touch, taste, sound and sight are processed.
When introverts receive stimulus from the outside world the pathway that the information travels through is a lot longer. The information goes through many areas of the brain including:
The right front insular,
The right and left front lobes and,
The left hippocampus.
The right front insular is an area involved with empathy, emotional thought and self-reflection. The Broca’s area activates self-talk and plans speech. The right and left front lobs, plan and select ideas and actions. The left hippocampus decides what things are personal and places them in long-term memories.
The long journey that the information takes when an introvert receives stimulus from the external world is the reason that introverts take longer to speak, react and make decisions.
Introverts have more gray matter in the front of their brains
A study published in the Journal of Neuroscience discovered that introverts have larger, thicker gray matter in their prefrontal cortex. The prefrontal cortex is the place in the brain that is linked to abstract thought and decision-making. Extroverts, on the other hand, have thinner gram matter in the same area.
What does this mean? It means that introverts devote more of their energy and resources to abstract thought while extroverts have the propensity to live in the moment.
Things may now make more sense to you, as an introvert. You can now understand that there are physical differences in your brain that make you prefer peaceful activities and self-reflection over highly energized situations.