What It Really Means To Be An Introvert, According To Neuroscience

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You probably hear the word bandied about all the time, and you may even identify as one yourself, but what is an introvert, exactly?

How do you define an introvert?

What does being introverted actually mean in day-to-day life?

The answers to these questions are not as straightforward as you may think because the common usage of the term is not as precise as it should be.

People talk about themselves or others as being introverts when they are actually referring to personality traits that have nothing to do with introversion.

To be sure that you are an introvert, you first have to understand what being one actually means.

While a simple, singular definition is hard to pin down, we can discuss the differences between introverts and extroverts and examine some of the characteristics often considered to belong to introverted people.

So let’s try and finally tackle that all important question: ‘am I an introvert?’

The Answer Lies In Your Brain

Being an introvert (or an extrovert for that matter) is actually all about how your brain rewards you for different activities.

It turns out that each personality type has distinct structures and activity levels in their brains, and these influence their behaviors and how they feel.


This neurotransmitter has multiple effects when produced in the brain, but the one we are going to focus on is how it acts as a reward.

Dopamine is released when we engage in an exciting external activity – eating a favorite food, going to a gig, meeting with friends – but the tolerance for it varies significantly between introverts and extroverts.

Extroverts simply can’t get enough of the stuff.

Their brains light up and they are filled with a euphoric happiness as a reward for doing something that arouses the mind.

They are hugely tolerant of dopamine and can easily cope with a stream of it being released.

Introverts, on the other hand, are far more sensitive to dopamine.

They will often experience the same initial buzz from it, but soon become overstimulated and weary.

This is why prolonged social interaction is so draining for introverts; their brains release more and more dopamine and it can interfere with their normal cognitive functioning.

The initial reward soon turns into a punishment, but the mechanism by which dopamine is released simply can’t tell when this tipping point occurs.

It continues to pump it out even when an introvert has entered a serious come down phase.

That’s why an introvert might really enjoy the first 30 minutes of a party before suddenly feeling an irresistible urge to run for the nearest exit.

If we were to picture an imaginary bar where they served dopamine instead of alcohol, introverts would be the lightweights whose heads feel fuzzy after just one drink, whereas extroverts can happily keep chugging away until kicking out time.


Dopamine isn’t the only chemical messenger in the brain that rewards us for certain behaviors.

There is another one that plays a big role in the separation of introverts and extroverts.

Acetylcholine gives us a smooth, calming type of happiness when we indulge in a little introspection.

When our thoughts turn inward, when we shut off the noise of the outside world, this clever little neurotransmitter puts a smile on our faces and a warm glow in our hearts.

Oh, but it only works for introverts.

Yeah, that’s right; it’s their very own magic elixir.

You see, while it is present in the brains of extroverts, they have very little in the way of a reaction to it.

Because they do not receive any reward when it is released, extroverts aren’t drawn to the quiet, self-reflective kinds of pastimes that introverts love.

For introverts, however, this more mellow and gentle high is precisely what they like.

There is far less risk of overstimulation with acetylcholine than there is with dopamine.

Thus, the lure of a good book, cozy night in, or deep one-on-one conversation is too much to resist.


It is has also been shown that the brains of introverts have a higher baseline level of arousal (activity in the brain) compared to extroverts.

In essence, they are doing more work in the background; more thinking, planning, and analyzing.

Why does this matter?

Well, due to these already elevated levels of arousal, introverts have a lower capacity for additional stimulation.

They have too much going on in their minds already, and adding further things to process only pushes them closer to their comfortable limit.

Gray Matter

Another way in which the brain of an introvert is different from that of an extrovert is in the thickness of the gray matter in certain regions of the prefrontal cortex.

This part of the brain is typically associated with abstract thought and decision-making.

This could be a result of the introvert’s fondness for extended periods of contemplation and deliberation.

It may also hold the key to their general slowness in making decisions.

Less Responsive To People

Researchers found that, when shown pictures of human faces and flowers, the response from introverts was no different.

Extroverts, on the other hand, displayed a higher response to the faces.

This suggests that, to an introvert, a human is no more intrinsically interesting than a flower or other object.

This once again demonstrates how the brains of these opposing personality types differ from one another and why introverts are less keen on social gatherings.

The Reward Of Social Interaction

After you consider the points above, you can draw one striking conclusion about why introverts and extroverts behave in different ways.

Much of the time, our actions are driven by a reward, whether that is instant or delayed, and it is this method of reward that separates these personality traits.

Introverts find little reward in prolonged social interaction and, in fact, experience the very opposite of a reward the longer this exposure continues.

Extroverts, however, receive a large reward for social interaction.

Introverts find low intensity activities which usually involve very few people – maybe just themselves – to be far more rewarding.

Extroverts get almost no such reward from these activities.

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So What Are Some Traits Of Introverts?

Now that we have identified the likely core difference between introverts and extroverts, what can we say about the former and their personalities?

There are so many different traits that have been attached to introversion, so why don’t we look at 10 of the most widely cited to see if they really do stand up to scrutiny.

1. Introverts enjoy spending time by themselves – TRUE

The whole aversion to too much social interaction does kind of confirm that an introvert is particularly happy when spending time by themselves.

This doesn’t mean they are always found engaged in solitary activities, but it suggests that they prefer them…to an extent.

They can enjoy spending time with others, but typically for shorter periods of time, in small groups, or when discussing deep, existential topics.

2. Introverts are shy – FALSE

Shyness is often thought of as interchangeable with introversion, but where introverts shun social situations to prevent overload, shy people do so because of a fear or anxiety they have about the negative judgement cast on them by others.

It is true that introverts are more likely than extroverts to be shy, but it cannot be said that all introverts are shy.

So there is a correlation, but no causation.

3. Introverts are antisocial – FALSE

Just because they sometimes find group activities more stressful, it doesn’t follow that all introverts are maladjusted, antisocial hermits.

It is just that introverts enjoy a different kind of socializing to extroverts; they aren’t so much into large gatherings full of unknown people, and are more likely to arrange intimate events in a quieter location like their house or a cozy corner of a coffee shop.

4. Introverts are daydreamers – TRUE

Thanks to the rewards they receive when looking inwards rather than outwards, they are very likely to enjoy getting lost in their heads.

Again, it’s not to say that extroverts don’t ever daydream, but you will catch an introvert at it far more frequently.

5. Introverts hate small talk – TRUE

A little bit of small talk is fairly typical even for introverts, but they like to quickly dispense with pleasantries and get into a serious conversation.

They don’t find it nearly as rewarding to indulge in gossip or the biographical accounts of your life; they just don’t find it as interesting.

6. Introverts are analytical – TRUE

The thickness of certain areas of gray matter discussed above suggests that introverts like to think carefully about things.

Another way to put this is that they like to analyze a topic, issue, or challenge from every conceivable angle over and over before deciding on the best course of action.

They tend not to act spontaneously, but prefer to contemplate their options before making their move.

7. Introverts are overthinkers – TRUE

The same thing that makes them analytical also makes them prone to bouts of overthinking.

An introvert’s mind may dwell on a certain train of thought for many hours, to the point where it actually becomes a problem in itself.

For the most part, looking inwards like this gives them some reward from acetylcholine, but even its effect wanes eventually.

8. Introverts prefer written communication – TRUE

Yes, it is very often the case that introverts will prefer to send an email, text, or even a good old fashioned letter rather than pick up the phone or meet with someone in person.

This allows them to avoid social interaction and remain cocooned in the bubble their minds create.

9. Introverts are highly sensitive to the people and energy around them – FALSE

While it is true that many empaths and highly sensitive people are introverts, the converse is not necessarily true.

It is quite possible for an introvert to have low levels of empathy and low sensitivity to their surroundings.

The confusion occurs because introverts find large social gatherings rather stressful.

However, this is not because they are sensing the emotions of other people, but because, as we have seen, they become overstimulated by the dopamine hit in such situations.

10. Introverts prefer to keep a small, but close group of friends – TRUE

Because of their penchant for more intimate gatherings, introverts will tend to have fewer friends in total.

They simply don’t care to keep casual acquaintances because these are less conducive to the type of activity that introverts enjoy.

Having to maintain lots of more distant relationships would eat up the alone time that introverts are so fond of, so they keep friendship group tight and few.

Now, the true and false statements above aren’t intended to apply to every introvert all of the time, but rather look at how the vast majority of introverts act and think.

There will always be exceptions to any rule and it is no different here.

About The Author

Steve Phillips-Waller is the founder and editor of A Conscious Rethink. He has written extensively on the topics of life, relationships, and mental health for more than 8 years.