Introvert / Extrovert: the difference is in your brain

Some time ago, I posted my thoughts on the misunderstood introvert. It seems to be a topic of widespread interest, since that post frequently shows up in my tracker stats.

This week I got a belated comment on the post from Nicole, who is studying clinical psychology at the graduate level in the midwestern USA. She added this insight to our earlier dialogue:

There is a theory that introversion/extroversion can be detected even before birth. Introverts tend to have a higher baseline state of arousal, therefore, it takes less to stimulate them.

Extroverts, conversely, have a lower baseline rate of arousal. Therefore, it takes more interaction to receive the same chemical/emotional feedback.

So, babies that are more active in the womb are correlated to extroversion.

And then Nicole returned with an update. Coincidentally, she had just discovered a newspaper article on this very topic. (“We all control the news, evidently”, she commented.)

The article was originally published in USA Today. Here’s an excerpt:

The attitude that there’s something wrong with introverted people is widely shared in society, where fast talk and snap decisions are often valued over listening, deliberation and careful planning. Extroverts seem to rule the world or, at least, the USA, which hasn’t elected an introverted president for three decades, since Jimmy Carter.”

The signals we get from the world agree that extroversion is valued,” says Sanford Cohn, an associate professor in curriculum and instruction at Arizona State University.

I note, in passing, that I took the same position in my post:  Western society rewards extroverts over introverts virtually every time. People respond to extroversion as a great virtue even if they haven’t explicitly thought of it in those terms.

But let’s move on and explore the new insight. It turns out that the distinction between introversion and extroversion is all in your head — but I mean this quite literally!

brain activityIntroverted children enjoy the internal world of thoughts, feelings and fantasies, and there’s a physiological reason for this. Researchers using brain scans have found introverts have more brain activity in general, and specifically in the frontal lobes. When these areas are activated, introverts are energized by retrieving long-term memories, problem solving, introspection, complex thinking and planning.

Extroverts enjoy the external world of things, people and activities. They have more activity in brain areas involved in processing the sensory information we’re bombarded with daily. Because extroverts have less internally generated brain activity, they search for more external stimuli to energize them. [emphasis added]

How counterintuitive:  the flamboyant extrovert has lower levels of electrical activity in the brain; the quiet introvert has more!

The information explains why it is so difficult simply to will yourself to behave more like an extrovert (or more like an introvert), contrary to your innate tendency. It also confirms Nicole’s observation:  if the distinction is rooted in electrical activity in the brain, you are an introvert (or an extrovert) even while you are still in utero.


40 Comments (+add yours?)

  1. Mary P.
    Dec 05, 2005 @ 08:04:00

    I like the idea that introverts are more autonomous, that they have more of what they need internally. Introverts are commonly seen as not needing stimulation, globally, as shying away from it altogether – which is, as it turns out, an extroverted perspective on it.

    The factor missed in that perspective is that there are TWO forms of stimulation: internal and external. The fact seems to be that, having a high baseline of internal stimulation, introverts need less external; it is not true that they avoid stimulation: they have lots – you just can’t see it from the outside!

    Thus, what is moderate stimulation to an extrovert is excessive to an introvert – but NOT because introverts don’t like/need stimulation.

    I love the way this idea loops around itself!


  2. Q
    Dec 05, 2005 @ 09:22:00

    It’s paradoxical, but it makes a lot of sense. I don’t know anything about the science here, but the explanation seems right to me.


  3. Sadie Lou
    Dec 06, 2005 @ 14:33:00

    I wouldn’t label my daughter as an introvert but she definately is able to entertain herself better independently.
    My son, who I would say is “shy” around people, has a hard time excersising his imagination by himself. He relies, heavily, on me and my husband to entertain him. My third child who is 3 months old was extremely active in the womb and I wonder which of his siblings he’s going to take after…
    I would say I’m an extrovert and my husband is an introvert.
    Interesting read.


  4. Q
    Dec 06, 2005 @ 15:13:00

    I’d assume your daughter is older because you mention her first. But it was my younger children who were better at amusing themselves. Their siblings functioned as built-in entertainment centres, so they were much less dependent on parental stimulation.

    I like to make a distinction between “introverted” and “shy”. I can talk about my innermost feelings without feeling a need to cover-up, and I am also effective as a public speaker. In other words, though I am quite introverted, I am not shy.


  5. Sadie Lou
    Dec 06, 2005 @ 15:18:00

    I don’t think the general poulation has a good understanding of the terms. I certainly don’t. My daughter is actually the middle child; it’s my son, the oldest, that is so high maitinence.
    Can you define the two terms for me? Maybe some characteristics of both?


  6. Q
    Dec 06, 2005 @ 15:39:00

    I posted my thoughts on the subject earlier: misunderstood introvert. One of the headings was, The defining characteristic of an introvert:

    ‘According to Myers-Briggs, introverts direct their energy to the inner world of thoughts and emotions and derive energy back from that inner world of thoughts and emotions. Extroverts, on the other hand, direct their energy to the outer world of people and things and receive energy back from that source.

    ‘I would emphasize the second half of the definition and ask, Where do you get your energy from? In my view, this is the best way to distinguish an introvert from an extrovert. …

    ‘Since I am an introvert, I get energy from turning inward. Long before I encountered Myers-Briggs, I said that I needed to be “alone in my own head”.’

    I hope this is helpful! The subject has always interested me.


  7. Sadie Lou
    Dec 06, 2005 @ 15:46:00

    That was helpful. I wonder how one is labeled if they get their energy from both?
    I don’t think, by your comments, that I am either, or.


  8. Q
    Dec 06, 2005 @ 16:50:00

    That’s likely true. It’s better to think in terms of a spectrum; some people are extremely introverted; some are a little introverted; some straddle the divide in the middle; some are a little extroverted; and some are extremely extroverted.

    I am definitely in the introvert camp. It sounds like you’re closer to the middle, but on the extroverted side of the continuum.

    Myers-Briggs is an organization which tests people to determine where they fit on four scales, including introversion/extroversion. You may be able to find a version of the test on line.


  9. Sadie Lou
    Dec 06, 2005 @ 17:12:00

    Thanks. I let you know if I find something.


  10. Ciuma
    Jan 01, 2007 @ 01:32:11

    How strange and interesting. That gives me a lot to reflect upon, and as an introvert, I will do that quite naturally. 😉 A couple years ago I found myself suddenly in awe of all extroverted people… I thought they were better than me. I wanted to be like them, to find the little things around me amusing. I wasn’t thinking in terms of introversion-extroversion, though. Now I understand that I am just drawn to different aspects of the world, not less(-er) aspects.


  11. Stephen
    Jan 10, 2007 @ 11:13:48

    Thanks for leaving a comment, Ciuma. I’ve been a little slow to acknowledge it, given the holiday season and other demands.

    I’m glad you’re sorting out those issues about your place in the grand scheme of things. Society needs reflective people like us, just like it needs those who prefer activities that are more obviously stimulating!


  12. Susan
    Oct 03, 2007 @ 03:33:41

    I find this interesting.. I am about to start on a course into counselling and I am fascinated by personality typing in general. Without any training I can intuitively see that each ‘type’ considers the way they do things as the superior and its always a surprise when something like this comes around and challenges their perspective.

    I guess what I’m trying to say is that even though extroverted society ‘misunderstands’ the introvert, I’m pretty sure the inverse also holds. I know many introverts that I talk with cannot understand how I am ‘energised’ by external parties. I sometimes think they view this as weak and I must be quite insecure to seek all this external interaction.

    Of course, I’m just an armchair philosopher… 🙂


  13. Stephen
    Oct 03, 2007 @ 12:19:27

    Thanks, Susan. I probably count as an armchair philosopher, too.

    I have mixed feelings about “typing” people — like all generalizations, they can mislead as much as inform. But I think C.G. Jung had some clever insights, including the distinction he made between introverts and extroverts.

    Introversion is a defining characteristic for me, both in terms of how I organize my life and in terms of how other people relate to me.

    I’m sure you’re right, that introverts don’t understand extroverts very well. As ever, we are largely trapped in our own subjective reality.

    I think I can distinguish between attention-seeking behaviour and extroversion. There is a distinction between not minding if you attract attention, and actively cultivating constant attention.


  14. juggling mother
    Oct 04, 2007 @ 14:44:19

    There was a “thing” on Tv the other day. said you can tell extroverts/introverts apart by their spit! Honestly:-) Take some brown tape, lick it until you run out of saliva. measure how long the piece is. Drip a drop of lemon juice on your tongue. repeat the brown tape thing. Extroverts do not react much to outside stimuli, so both pieces of tape should be of similar length. Introverts react strongly to outside stimuli, their nopieces of tape should be of vastly different lengths. He did it with several hundred (I know, statistically small, but not minute) people on the street and also did a “official” questionnaire with them. It worked pretty much every time.

    Weird huh?:-)


  15. Stephen
    Oct 04, 2007 @ 14:47:44

    Yep, that’s a weird one! I hope the researcher was on a government research grant.


  16. Ryan
    Oct 20, 2007 @ 21:30:38

    *sigh* i never seem able to decide really on whether im extraverted or intraverted. Dont we all focus dominatantly on our own motives and ideas? ive always been creative in ways (like drawing, writing, and music) and my parents always said i was quiet and mellow as a child. On the otherhand at school i was usually in trouble for talking in class, not following directions and being rowdy and disruptive. i can never put my finger on which is the real side.
    i can always feel good when im around friends or at parties with them and can turn a switch on and talk boldly and openly to strangers and make friends quickly. but after a while i kind of forget about constantly meeting new ppl and stuff and just do my own thing. (usually in front of my tv, or with the same group of friends.) the last reason is that ive never been one of those ppl who are painfully silent at all times, just in odd situations when i can get insecure and just feel crippled by my inability to say anything that wouldnt sound awkard.


  17. Stephen
    Oct 21, 2007 @ 08:48:23

    You sound like my wife, who straddles the border between introversion and extroversion (perhaps coming down a little on the introvert side). We shouldn’t think of this as a dichotomy — like a light switch which is either off or on.

    It’s a continuum. I am strongly introverted, whereas my wife is only mildly so — and is quite capable of playing the extrovert when the mood is upon her.


  18. Michael James Cook
    Jan 15, 2008 @ 16:14:10

    The photo of brain activity was just fabulous. I have a request. I am currently living in Mexico and I am currently putting together a play has a fund raiser for a local orphanage. Its an adaptaion from the first part of my book “The Diamond Formation” I would love to use the image on a Big Screen as a back drop, its just perfect for my script and the theme of the play.
    Please consider my request.
    Yours faithfully
    Michael James Cook.


  19. Stephen
    Jan 15, 2008 @ 19:07:30

    Hi, Michael. I agree that it’s a very cool image! But I can’t give you permission to use it, because it isn’t original to me.

    If you click on the image, it will take you to the site where I found it. You’ll have to ask them for permission to use it. Good luck with your play! ("Break a leg!")


  20. Bob the Chef
    Jan 24, 2008 @ 11:54:27

    Interesting thought: actors can be introverted, but play extroverts. Does the opposite occur?


  21. Emil
    Mar 19, 2008 @ 23:41:30

    I find all of this so interesting….I consider myself an introvert, but at times, I’m an extrovert. It’s weird how I could be really shy around some people and then really open towards other people. Is there such a thing as a ‘mixed personality’ where someone could have two different personalities? I’m always on the fence because sometimes I would be really into myself and other times, I’m just out there partying and socializing. But I like to consider myself an introvert 🙂


  22. Stephen
    Mar 20, 2008 @ 16:00:41

    You may be on the cusp of the split between introvert and extrovert, so you can adopt either role. But my experience isn’t so different from yours.

    I find my ability to take the lead role in a conversation depends a great deal on who I’m with. If I’m with someone who is talkative, I reflexively fall into listening mode, which comes naturally to me. I’m not assertive enough to insinuate myself into a conversation if the other person likes to do all the talking.

    But with the right sort of companion, I can become downright voluble. I have one friend, in particular, who is always happy to explore whatever is going on in my life. Once I get started, I have to remind myself to invite her to speak once in a while!

    “Introvert” doesn’t mean we have nothing to say. It’s just a matter of how assertive we are in conversation.


  23. Kal
    Mar 24, 2008 @ 17:58:13

    I was 26 years old when I found out I was an introvert last year. I spent my life until that time wondering if I was crazy. You can just imagine how relieved I was to know that my behaviour is normal for an introverted person. I am unable to shut off my ability to think and daydream. It is so good to know there are other people like me. Hello!!!!!!!!!!, other people like me (introverts I mean).


  24. DeaneRenata
    Apr 20, 2008 @ 00:38:51

    I am definitely a hard introvert, no question about it. I have trouble making friends and mixing in with large groups, there is not a whole lot of extroversion about me. Unlike Ryan I don’t border between the two, and parties certainly don’t turn me on. They make me feel bored. If anything they make me feel uncomfortable, afraid, and without security so I shun them altogether. I have never been to a really big gathering party (maybe one of two smaller ones). Not when I was a kid, and not now. I was too scared. I still am. I was a big loner when I was a kid and I shunned a lot of the other kids at school. They were not interesting. I still am a lone wolf as an adult. Like you said I draw my energy from my inner thoughts and outward things sometimes bore me.


  25. DeaneRenata
    Apr 20, 2008 @ 00:39:47

    Hey Kal, I think and dream a whole lot too. It’s a curse I know. And I feel really good that you do the same exact things I do. 🙂


  26. DeaneRenata
    Apr 20, 2008 @ 00:42:28

    And being introverted does not make us losers, neither can we help what we are, as research has proven it is due to where the electricity is applied in the brain is how people act like they do. 🙂 So I have more electricity…ha ha…I never knew I was such a zap. Lol.


  27. Stephen
    Apr 20, 2008 @ 08:50:14

    This issue resonates at a very personal level for so many of us. “There are two kinds of people,” we often say. When Carl Jung identified the two kinds as introverts and extroverts, he was really onto something. Many of us are defined in large part by where we fall on this continuum.

    This post is consistently in my top ten, in terms of how many page views it receives. It’s two and a half years old, but it still attracts about 300 hits per month.

    It’s always a wise decision to build on your strengths (not your weaknesses!). If you’re the sort of person who is prone to daydreaming, that can be an asset. Maybe you’re a possibility thinker; someone who is creative, or devises new ways of doing things, or new solutions to challenging problems.

    Of course, we introverts also have to develop enough social skills to enable us to function in group situations. But it’s probably a mistake to go into a career that puts you in the public eye all the time. (That’s an example of what I mean by not building on your weaknesses.)

    I’m a big believer in complementary skills. Society needs both introverts and extroverts. Which means that we introverts must embrace our introversion and learn how to make the most of it: even if society doesn’t always value us as highly as it ought to.


  28. Sophie
    Aug 04, 2008 @ 15:31:34

    I’ve always been labled as introverted by my mother, until recently I didn’t fully understand all of the ideas behind this “introverted” personality and thought this simply meant I’m very shy and don’t socialize well. I agree with the folks that have posted on here that are introverts as well when they say they feel more at ease after reading this article. I’m not alone!
    I’m also a recovering alcoholic with 3 years clean and sober. This has gotten me thinking also, (then again, what doesn’t get me thinking) about the many factors of introversion that may have played into my alcoholism. On one hand I always have strongly believed that people are born with this addictive personality, just like an introverted personality. On the other hand I can’t stop wondering what I would have been like without the constant selfish and negative alone time to just be pensive and miserable. Most of me thinks that I would be in the same boat with my addiction. But it is still something interesting as well as perplexing to ponder…


  29. Stephen
    Aug 04, 2008 @ 15:54:24

    Congratulations on 3 years of sobriety! That’s quite an achievement!

    I can relate to your scenario, where your mind dwells on negative thoughts. I’m somewhat depressive myself, although I don’t think there’s a direct link between depressive tendencies and introversion. I’m sure lots of introverts are perfectly content in their solitude.

    But it’s true, sometimes we introverts just need something to distract us from our idle thoughts! I find it can be a problem if I wake up during the night and can’t get back to sleep because I’m brooding about something or other. These days, I keep my iPod by the bed, so I can contemplate some good music instead.


  30. Valerie
    Sep 23, 2008 @ 19:27:19

    Being an introvert myself, and having all three of my children be introverts, and being married to yet another introvert. My entire family is deeply introverted. I can’t say we dwell on the negative. I can’t say that any of us are depressed, as we celebrate each individuals unique qualities. It’s quite alright to be who you are, where you are, and it’s quite alright to want to be alone. I have a great sense of humor and I seem to infect everyone in my family with it. When I choose to engage, it’s usually only with my family and one or two close friends. We have very close, intense and intensely satisfying relationships. When my mind won’t let me sleep at night, I read, I watch something boring on TV to make me sleepy, or I just give up and get on the internet and chat with others….being social on the internet is much better than in person, I don’t have to hear the small talk. I don’t have to hear the phone ring, and I can sign off when I have had enough.

    No one in my family finds solitude to be any sort of a problem. In fact, my oldest daughter has also married an introvert. We like it this way. Enjoy who you are, find activities that GO WITH AND CELELBRATE WHO YOU ARE AS AN INTROVERT. Be happy with who you are!


  31. Stephen
    Sep 23, 2008 @ 20:23:21

    Thanks for the encouragement, Valerie!


  32. Kal
    Sep 27, 2008 @ 17:56:27

    Valerie you are so fortunate to have people around you that are introverts. It is very difficult for me to find introverted people to be with, and I am not good at making friends which makes it twice as hard. You are very blessed to have an introverted husband. For me I am not married and I have to accept that I may never be, because I can’t find men who are able to tolerate my silent reflective world for very long. However there are many good sides to being and introvert and they are worth celebrating.

    I find the internet to be a blessing for introverted people. I can find so many things to read and it is easier to talk to people on the internet that in person. I find that I am able to read people’s personality a lot better than others. It is very easy for me to tell when someone is being false or pretentious. This might sound judgmental but it is very true for me.


  33. J.H.
    Oct 23, 2008 @ 03:11:42

    As a classic introvert myself, I highly recommend the following book: The Introvert Advantage: How to Thrive in an Extrovert World by Marti Olsen Laney. This book outlines the introvert world in various perspectives (i.e. scientifically, physiologically, psychologically, socially)

    Book Description:
    At least one out of four people prefers to avoid the limelight, tends to listen more than they speak, feels alone in large groups, and requires lots of private time to restore their energy. They’re introverts, and here is the book to help them boost their confidence while learning strategies for successfully living in an extrovert world.

    After dispelling common myths about introverts-they’re not necessarily shy, aloof, or antisocial–The Introvert Advantage explains the real issues. Introverts are hardwired from birth to focus inward, so outside stimulation-chitchat, phone calls, parties, office meetings-can easily become “too much.”

    The Introvert Advantage dispels introverts’ belief that something is wrong with them and instead helps them recognize their inner strengths-their analytical skills, ability to think outside the box, and strong powers of concentration. It helps readers understand introversion and shows them how to determine where they fall on the introvert/extrovert continuum. It provides tools to improve relationships with partners, kids, colleagues, and friends, offering dozens of tips, including 10 ways to talk less and communicate more, 8 ways to showcase your abilities at work, how to take a child’s temperament temperature, and strategies for socializing. Finally, it shows how to not just survive, but thrive-how to take advantage of the introvert’s special qualities to create a life that’s just right for the introvert temperament, to discover new ways to expand their energy reserves, and even how, when necessary, to confidently become a temporary extrovert.


  34. Stephen
    Oct 23, 2008 @ 07:42:42

    Thanks for the book recommendation, J.H.


  35. Trackback: Can the type functions be explained by neuroscience? - Typology Central
  36. Trackback: Can the type functions be explained by neuroscience? - Page 2 - Typology Central
  37. SomethingTangible
    Apr 19, 2009 @ 23:00:04

    Very interesting read. This is a purely philosophical thought but I wonder if extroversion is more rewarded in our society, partially because extroverts tend to get more stimulation and therefore they buy more products to keep them entertained and stimulated.


  38. Only3Penguins
    Apr 28, 2009 @ 17:40:21

    I’ve known forever that I’m an introvert, but some of the information in this post and the comments is making me wonder whether my introversion affects more than I realize. Namely, whether a stronger reaction to external stimuli can be blamed for what an awful eater I am. There’s much that I don’t or won’t eat because of the smell or texture or just the look–stuff that millions of other people love (i.e. I don’t like pizza! Gasp!). I don’t use many condiments. I don’t dip, I don’t sprinkle, I don’t season. I order burgers plain (bun, meat, bun, done!). There’s not a lot of variety in my diet and now I wonder whether my strange aversion to flavorfulness is just another case of introverted oversensitivity to external stimuli. I also suspect my introversion is why I don’t like to drive. It demands constant attention be paid to what’s in front of me, which precludes slipping off into my head.


  39. Zac
    Apr 28, 2011 @ 12:37:52

    This helps to explain the alcoholic introvert who drinks to slow down their mind and then behaves like an extrovert.


  40. Trackback: In Defense of the Introvert

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