27 October 2011

This is your brain on introversion

It's useful to remember that whether we are introverts or extroverts is all in our head.

Are you an introvert or an extrovert? Credit: iStockPhoto

By Mara Flannery

As I walked back from the Cosmos office yesterday, I thought about how I couldn’t wait to get home just to sit in my bed, alone, and Google things until my brain hurt or watch Mad Men until someone realised I was turning into a hermit and came to find me.

I thought about why I think more in my own head and talk out loud less than others as I passed girls shouting and laughing to each other on the street. I thought about why I need hours alone every day just to recharge. My thought process scurried on and on.

Since of course I ended up thinking about the brain and what causes me to be such an introvert, I remembered a class I took about a year ago where we discussed some recent research looking at differences in the brain between introverts and extroverts, and whether neuroscience could explain (at least partially) why we act the way we do.

Don’t get me wrong. I love being at the Cosmos office surrounded by interesting people all day. And I love going to class to learn new things. I love hanging out with my friends. But after a few hours doing any one of these things, I need an amount of time to, well, chill out.

The concept of introversion versus extroversion dates back to the early 1900s with Carl Jung’s personality theories. Jung’s theories said that personality types are “distinguished by the direction of general interest or libido movement” of a person, the extrovert as directed towards the outer world and the introvert as directed to the inner self. In modern terms, introverts are often not misanthropic or even shy, we just get tired out by people.

Extroverts, on the other hand, get their energy from people and are almost always bored by being alone. For an introvert, recharging alone is as regenerative and necessary as sleep. I often think that introverts understand extroverts, in that we can see the way they play out loudly and clearly in the world. But extroverts sometimes see introverts as offensive or self-alienating and they cannot see why we would ‘want to be alone’.

But there is at least one neurobiological explanation for us wallflowers that our party-animal friends can’t argue with! Although it is not recent news, science has discovered by conducting brain scans that introverts process information differently than extroverts. Researchers at a couple different universities in the U.S.

Almost a decade ago examined healthy subjects by taking PET, or positron emission tomography scans of their brains while they were asked to ‘think freely’. The PET scans, which generate hi-res activity areas based on where blood flows in the brain, showed that introverts have more activity than extroverts in the anterior (frontal) thalamus and the frontal lobes of the brain, areas which control making plans, remembering things and problem solving.

Extroverts had more going on in the temporal lobes, anterior cingulated gyrus, and posterior thalamus, three different parts of the brain which probably control the way we interpret sensory information such as when driving, watching or running. Since introverts rely on the self for stimulation while extroverts rely more on outside sources for entertainment, this makes complete sense.

These are only correlations. My fascinating extrovert friends who are driven by sights and sounds also probably have a little introvert happening. It is interesting that almost all developed countries value extraversion in people, and most of the world’s politicians and leaders throughout history have been extroverts, but probably with a little introvert in themselves or an introvert assistant to hold the reins.

Being an extrovert does not determine your level of happiness in life, it just oversees the way that you choose to get happy. And I don’t think that neuroscience can explain everything without psychology. For example, I wonder if an extrovert could change into an introvert based on an emotionally impactful experience they had, or vice versa. This is where research should look next. Most people have a mixture of both personality types, but being shy or outgoing, guys, is all in your head, literally.



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