How Introvert and Extrovert Brains Differ: 6 Differences According to Science

introvert and extrovert brains differ

A glamorous social event OR a quiet evening at home with your favorite book? If you chose the former – then you’re an extrovert, the latter one – then you’re an introvert. Unlike extroverts, introverts prefer pets over people and deep conversations over small talks. But, do you know that these behavioral preferences are the result of differences in the structure of your brain?

Yes, an introvert brain is wired differently.

Introverts Vs Extroverts

Introvert and extrovert are the terms used to define two very contrasting personality types. The terms were coined by the famous psychiatrist, Carl Jung, in the 1920s. Extroverts and introverts differ in the way they are energized.

While extroverts gain energy from social interactions and stimulating external environments, introverts are overwhelmed by these things. They prefer quiet and solitary environments and need alone time to unwind. Usually, people are not completely extroverted or introverted, but a mixture of both. However, everyone is more inclined towards a particular personality type.

Introverts and extroverts differences
How Introvert and Extrovert Brains Differ: 6 Differences According to Science

Read 19 Signs You’re an Introvert in a Loud World

Now, let’s dig deeper into the biochemical story and brain structure of these two personality types. Read on to know why introverts and extroverts think and behave differently.

1. Difference In The Blood Flow To The Brain

There are different types of neurotransmitters in the brain. Each neurotransmitter has a certain pathway in the brain, through which it travels and directs where the blood circulates and regulates how much of it flows to different brain regions. Further, the route and quantity of the blood flow influence what parts of the brain and central nervous centers are “turned on”. The part of the brain systems activated determines our response to the world and behavior.

In an experiment, introverts and extroverts were asked to lie down and relax while a very small dose of radioactivity injected into their bloodstream. When their brains were scanned, it was found that introverts have more blood flow to their brains. Also, the blood traveled along different pathways in the introvert’s and extrovert’s brain.

While the extrovert attended externally to what was happening in the lab, the introverts were attending to their internal thoughts and feelings. It seems the introvert’s pathway is more complicated than that of extroverts.

2. Extroverts Rely On Neurotransmitter Dopamine

Dopamine, a crucial neurotransmitter, is a sort of reward for the brain and also influences our mood and feelings. It motivates people to achieve things and seek rewards. When dopamine is secreted, we become more alert to the activities in our surroundings and motivated to undertake behaviors that are considered risky. Dopamine produces an instant feeling of euphoria in us when an externally rewarding situation happens.

Read How to Supercharge Your Dopamine Levels Naturally

This chemical in our brains plays an important role in the behavioral differences between introverts and extroverts. The amounts of dopamine secreted are the same for introverts as well as extroverts. But the way both of these personalities react to the dopamine secreted is different.

There is a clear difference in the dopamine reward network, which is more active in an extrovert brain. Extroverts are known to have shorter dopamine pathway. Information from the outside world like sound, images, light travels a shorter pathway ( i.e – “quick response” areas of the brain where taste, touch, sight, and sound are processed), before entering an extrovert’s brain. 

Therefore, asking a girl for a date, talking to strangers, taking risks comes quite easily to extroverts than introverts. It’s the dopamine, that extroverts are always enthusiastic about new endeavors and feel rewarded socializing with people. Dopamine and intensity of the stimulation act as a cue that they are achieving their goals.  Extroverts have low sensitivity to dopamine, so they need this chemical in large amounts. On the other hand, introverts are highly sensitive to dopamine and feel overstimulated, according to the 2002 book, The Introvert Advantage, by Dr. Marti Olsen Laney.

Extroverts have a shorter dopamine pathway and introverts have a longer acetylcholine pathway.
How Introvert and Extrovert Brains Differ: 6 Differences According to Science

3. Introverts Rely On Neurotransmitter Acetylcholine

Introverts are more dependent on acetylcholine, which is also a neurotransmitter, but it is slightly different than how dopamine works. Acetylcholine, like dopamine, is a reward-inducing neurotransmitter, but the reward is more internal.

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