June 22, 2010
Personality Linked To Sizes Of Brain Parts

If you want to turn yourself into an extravert you'll need to find a way to grow your medial orbitofrontal cortex.

Personalities come in all kinds. Now psychological scientists have found that the size of different parts of people's brains correspond to their personalities; for example, conscientious people tend to have a bigger lateral prefrontal cortex, a region of the brain involved in planning and controlling behavior.

So the people I especially like in the work place have a big lateral prefrontal cortex. Good to know. I'm going to complement certain people for their fine lateral prefrontal cortexes.

Psychologists have worked out that all personality traits can be divided into five factors, commonly called the Big Five: conscientiousness, extraversion, neuroticism, agreeableness, and openness/intellect. Colin DeYoung at the University of Minnesota and colleagues wanted to know if these personality factors correlated with the size of structures in the brain.

For the study, 116 volunteers answered a questionnaire to describe their personality, then had a brain imaging test that measured the relative size of different parts of the brain. A computer program was used to warp each brain image so that the relative sizes of different structures could be compared. Several links were found between the size of certain brain regions and personality. The research appears in Psychological Science, a journal of the Association for Psychological Science.

Imagine employers doing brain scans to spot people who are especially conscientious. What's strikes me: Some personality traits are easier to spot. Extraverts stand out. You don't need to scan brains to identify them. By contrast, conscientious people aren't as obvious.

A bigger medial orbitofrontal cortex might make you more extraverted.

For example, "Everybody, I think, has a common sense of what extraversion is someone who is talkative, outgoing, brash," says DeYoung. "They get more pleasure out of things like social interaction, amusement parks, or really just about anything, and they're also more motivated to seek reward, which is part of why they're more assertive." That quest for reward is thought to be a leading factor in extraversion. Earlier studies had found parts of the brain that are active in considering rewards. So DeYoung and his colleagues reasoned that those regions should be bigger in people who are more extraverted. Indeed, they found that one of those regions, the medial orbitofrontal cortex it's just above and behind the eyes was significantly larger in study subjects with a lot of extraversion.

What I want to know: Once prospective parents gain the ability to choose genes for their offspring that influence personality development which traits will they go for? I hope future generations aren't all extraverted. I like peaceful settings and people who can shut their yaps. Agreeableness: Too many people with this trait could create too much of a herd tendency.

Share |      Randall Parker, 2010 June 22 05:53 PM  Brain Personality


Comments
Lono said at June 23, 2010 7:57 AM:

Randall,

I think most of the herd is simply going to ask doctors to make their children attractive and smart. I mean - it's not like most Densans can really comprehend the implications of making more subtle, purposeful, changes to their offspring.

And this will probably be just fine - because if future generations are truly more intelligent they will seek to find their own ways to modify their behavior for their own adavantage (and possibly Humanity's advantage if they are empathetic enough).

Then it will break down into practically a religious war between the top intelligensia over weather Homo Sapiens should be ruled with an Iron Fist or a gentle touch.

I, being highly emapthetic, believe the gentle touch approach will be the more humane approach - until Humans can be uplifted en masse into a hightened general awareness.

Oh, how I look forward to the day I no longer have to dumb it down just to have a normal conversation with my fellow man!

(present company excluded - of course)

Fat Man said at June 23, 2010 10:23 AM:

This method cannot distinguish between cause and effect. Bicyclists have larger calf muscles. That is clearly an effect of cycling.

We know that neurons grow and change in response to activity. Is an enlarged medial orbitofrontal cortex a cause of extroversion or an effect of extroversion?

Recent articles about the genome research of the past few years has stated that relationships between identifiable loci and diseases are proving difficult to identify. Should we expect an easier ride for personality traits.

Randall Parker said at June 23, 2010 7:51 PM:

Lono,

If the masses choose to make their children smarter then the children will be smart enough to choose personality traits for their own kids.

Seems inevitable that at some point lots of really smart people are choosing offspring personality traits. Well, what sorts of calculations will they make? How will they weigh not just the 5 big personality traits but lots of other traits as well? Sex drive? Level of sensitivity to salty taste? Curiosity? Thrill-seeking? Personality characteristics that make people lean left or right politically?

I do expect people to become much better looking. I'm expecting women to go for blue eyes and blonde hair for their daughters in a big way. What about breast size? I'm thinking bigger.

ASPIRANT said at June 24, 2010 4:40 PM:

>>> I'm thinking bigger.

Depends. If absolutely everyone has these monstrous breasts, then saner sizes will become more popular in response. Pendulum swings etc... whatever.

People themselves will be a fad. If they ever perfect technology so that everyone stays 28 forever, your age may still be betrayed by your face... Green eyes? That's so (20)80's.

ASPIRANT said at June 24, 2010 5:00 PM:

>>Bicyclists have larger calf muscles. That is clearly an effect of cycling.
Yep. Slight tendencies toward certain behaviors can be amplified into huge significance through habit. This is what I believe (but everyone here already knew that lol)


>> Seems inevitable that at some point lots of really smart people are choosing offspring personality traits. Well, what sorts of calculations will they make? How will they weigh not just the 5 big personality traits but lots of other traits as well? Sex drive? Level of sensitivity to salty taste? Curiosity? Thrill-seeking? Personality characteristics that make people lean left or right politically?

My biggest fear is that some misguided and unwise people, from any social class, might, en masse, make some horrible choice whose consequences we can't take back. For example, vast swaths of middle America are going to churn out huge numbers of wanna-be Wall Street and DC power brokers, because of their asinine belief that they can reap the greatest rewards out of life that way, like Fox News tells them. Don't think they won't; I know these people. They've bought the party line completely.

We're going to be overrun with people who are completely dedicated to their own families and social groups to the detriment of all others, and will have no problem reducing the value of the lives of those outside their group to nearly nothing.

Liberals are admittedly less frightening... They'd most likely choose some even more overly-nice, very agreeable and gullible version of who they themselves already try to be.

Even if I believe the impact of genes on our current stock of humans is relatively limited, I do believe that in the wrong hands this kind of knowledge can be extremely destructive.

ASPIRANT said at June 25, 2010 4:57 PM:

I have question... When it's no longer possible to gauge a woman's biological value by looking at her face, when everyone is uniformly beautiful and immortal, what do you think that will that do to Roissy's "mating market"? I'm guessing hypergamy is going to figure big time, but I don't think I've worked out the specifics.

Do you think people will all in all be happier or not?

Randall Parker said at June 26, 2010 7:09 PM:

Aspirant,

Aside: Why do you use all caps for your pseudonym?

When everyone is beautiful: They will still have very different personalities, posture, intelligence, accomplishments, status, money. Plenty of ways to choose among them.

Will people be happier when everyone is beautiful? I know I'll enjoy it more.

Mthson said at June 27, 2010 1:58 AM:

All the filtering to find the right level of physical attractiveness (not too much higher, not too much lower) will suddenly become obsolete.

Seems like a very humanitarian event to work toward. Give the benefits of the few to the many.

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