I am an introvert. However most people don’t believe me, partially because, I tend to exhibit the behaviour of extroverts. Many of us do, as we learn how to mask our true personality. We know that extroversia is the preferred way of existing. However, neither introverts nor extroverts can help themselves – we are wired the way we are.

There are several studies showing physical differences inside the brains of an introvert and an extrovert.

Similarly to hetero- or homosexuality, our skin or eyes colour and fingernail length, extroversia or introversia are not chosen or adopted throughout the life but pre-determined before we’re even born.

We don’t choose to be an introvert or an extrovert. However, we can still choose our behaviour regardless of the personality.

The details are fascinating. Let’s have a little dig in together.

Intro vs Extro

Extroverts are the ones who tend to be bubbly and loud, surrounded by millions of friends and feeling restless or guilty if they stay at home and do “nothing” for too long.

Introverts, on the other hand, are often seen as anti-social, self-absorbed and sometimes weird.

Extroverts are loved by everyone and noticeable everywhere; they are loud and fun and everyone wants to be with them.

Introverts are quiet; they don’t have many friends and no one really notices them.

Extroverts become successful business people, managers and leaders, whereas introverts work in a library or get involved in some boring scientific work.

Extroverts are always happy and introverts are always depressed. Extroverts are always stressed and introverts are always mellow.

Or are they?

In fact, this is not true!

While these statements can be true in some cases (and to some extend), they are all just generalisations.

I am excited to take you inside an introvert’s brain today.

Brain Engineering 

Although introverts are often seen as shy, reserved and typically self-centred individuals, they are simply thinkers. 

Introverts have an aptitude for developing ideas, undertaking strategic planning and endeavouring to understand and rationalise concepts – which makes them great scientists and writers. So why exactly is it that introverts can appear so “anti-social”, quiet and selfish?

Believe it or not, introverts are the way they are because of their brain. The way their brains are wired is different to the way extroverts’ brains are wired. One scientific method that has been used to explore these differences is a positron emission tomography (PET) scan.

PET scans are used to look at how our bodies use substances such as glucose, ammonia, water and oxygen. We need to observe this to see how and where molecules move through your body, and where they are being used. Computers can analyse the data and produce a picture of what is happening anywhere in the body, including the brain. PET scans are often used to find potential diseases or damages; however, they can also help us understand different personalities. Read on to find out how.

Peak Into the Brain… 


One particular study used PET scans to observe the blood flow in the brain of an extrovert and an introvert while both of them were resting.Amazingly, introverts’ blood flow is richer than extroverts’, even when they are resting. However, this stronger blood flow is connected to the part of the brain responsible for problem-solving and planning. Why is this important? Well, more blood flow causes more stimulation – therefore, while an introvert is resting, they are still very active inside the brain.

On the other hand, extroverts’ blood flow was shown to target the sensory part of the brain, travelling on a straight “highway”. Therefore, while introverts were absorbed in their thoughts, extroverts were actively analysing what was happening in the environment around them. Don’t get me wrong, neither blood flow is bad; they’re just different.


One chemical that provides great insight into introverts and extroverts is called dopamine. In plain language, dopamine is a signal transmitter in the brain which is also very important for movement, attention, alert states, learning and reward-motivated behaviour. Dopamine is crucial for human beings, but too much of it causes hallucinations and paranoia, and too little causes depression, lethargy and misery.

Now, the “right” amount of dopamine is different for an introvert and an extrovert. Introverts are highly sensitive to it and don’t need too much stimulation to get over-excited and anxious, whereas extroverts crave more of it to simply feel well.

Introverts, in fact, rely on a different chemical – acetylcholine – which is a neurotransmitter in both the peripheral nervous system (PNS) and central nervous system (CNS) in many organisms, including human beings. An introvert’s brain does not like dopamine much (because it can easily over-excite), hence it prefers to use acetylcholine; conversely, an extrovert’s brain simply does not like acetylcholine as much as an introvert’s brain does.


Another reason why introverts and extroverts are so different from one another is relatively hard to understand if you are not an introvert (kidding!). According to “The Introvert Advantage” by Marti Olsen Laney, the pathway that acts as a highway for chemicals or a transmitter for stimulus is different in extroverts’ and introverts’ brains.

The amygdala is the emotional centre in our brain. Whatever we feel needs to be transmitted to the amygdala for further analysis. The brain receives the data and simply makes sense of it. However, we now know that different brains carry out this process differently.

Basically, introverts rely on different chemicals in the brain than extroverts, as well as different-sized pathways. Different chemicals affect different nervous systems. Therefore, an introvert and an extrovert are effectively two different types of humans.  This is why introverts need to take breaks from people to recharge, while extroverts are recharging while (and by) interacting with others.

Now, imagine an introvert hanging out with an extrovert! It would most likely be draining for one and puzzling for the other. This sentence explains it better than I can paraphrase it:

“…After an hour or two of being socially ‘on’, we introverts need to turn off and recharge. My own formula is roughly two hours alone for every hour of socialising. This isn’t antisocial. It isn’t a sign of depression. It does not call for medication. For introverts, to be alone with our thoughts is as restorative as sleeping, as nourishing as eating.” [Source: “The Rise of the Introvert”]

If you are still embarrassed or ashamed to admit that you are an introvert, don’t be. Be proud of being different, no matter whether you are introverted or extroverted. I believe that understanding yourself is crucial. It is even more important to accept yourself. Knowing who you really are can assist you in living more happily, easily and brightly without fear, doubt or regret. Building your business brand would be impossible without understanding yourself.

Explore further: Susan Cain’s TED Talk “The Power of Introverts” and Lisa Petrilli’s article “The Introvert’s Guide To Boosting Your Career Through Blogging”.