Is Personality Genetic or Epigenetic?

[ArcadeWurm]

I began to wonder this the other day when my friend was making the claim that he became extroverted his senior year of high school after being introverted his whole life before that. My initial thought was that is complete bullshit and most likely he has just been forcing himself to talk more while still being introverted. But the more I think about it he definitely was introverted before that and seems to be legitimately extroverted now. I guess there is no way to really know whats going on inside his head but he is the most energetic person I know now and is always talking/ in the mood to talk.

I find the topic of Epigenetics to be particularly interesting because it challenges the claim "its genetic" in the sense that most things about people that we assumed them to be born with were actually triggered by some environmental factor and therefor are not inevitable. One interesting example I read about was these two identical twins, where one ended up developing autism and the other did not.

So to get to the point, can our personality be influenced by environment factors? or in other words can a person born an introvert become and extrovert or the other way around. I would like to think that in the early stages of our lives this can be changed by our environment.

 

[SpaceYeti]

Frankly, I think it's silly to presume a person's personality is anything besides a combination of natural and assumed traits. I've been calm my entire life. That's not to say I don't get goofy or hyper or anything, simply that, in a situation I'm not familiar with or which must be taken seriously, I calmly inspect things in order to determine what's appropriate. I never threw temper tantrums, thinking people foolish for simply making the problem bigger than it is, as far back as I can remember. Perhaps it caused me not to make a case for myself, though. Either way, this is simply a part of how I work. To say I learned it would be silly, as I've been that way since birth, according to my mother and father.

However, I have also learned how to interact with people. It's draining to me, but I can do it, and I can do it well. Interacting with people in any meaningful sense would be incredibly difficult if you didn't learn how to somehow. I remember, distinctly, when I learned to consider how other people feel. I was very young, and dismissing what my cousin was saying. I was confused when she got upset and went to her room, deciding not to play after all. My aunt explained what I had done, and asked how I would feel if someone did it to me.

Some qualities are innate, some are learned. It's that easy.

 

[SpiralHacker]

My hypothesis is that a lot of our personality traits, including the ones covered by Jungian personality theory, are mostly set at birth, or within the first two years.

Researchers who wrote and published this paper on some personality traits being tying to structural variances in the brain said in news articles that they believe these traits they were looking for are set at birth. If this is true, perhaps the regions that scientists are now looking at for what causes extraversion are also set at birth (there are studies suggesting it is related to the size and activity of the orbitofrontal cortex and a few other regions).

 

[rrgjl]

I'd have to agree with SpaceYeti. It's that simple.
Partly it also depends on your definition of personality. When someone is very insecure because of past experiences, has this insecurity become part of their personality, or is it on top of their personality?

 

[ArcadeWurm]

Spaceyeti I get your point and I agree. But I was mainly asking whether or not a core personality trait (such as introversion vs extroversion) can be changed by environmental factors. Is it a viable claim that my friend became extroverted? or must I assume he is still introverted but has just forced himself to be more social?

 

[rrgjl]

Seems kind of hard to research. Don't know what the literature says about this, but you'd have to do some kind of psychological testing on newborns to be definitive I'd say.

 

[SpaceYeti]

Spaceyeti I get your point and I agree. But I was mainly asking whether or not a core personality trait (such as introversion vs extroversion) can be changed by environmental factors. Is it a viable claim that my friend became extroverted? or must I assume he is still introverted but has just forced himself to be more social?

I would say that either he was not extroverted and became it, he is not extroverted but is acting it, or he was introverted and changed to extroverted, and whichever case it is doesn't really matter, so long as he's happy.

Were I forced to guess, though, I'd wager that he was always extroverted, but he was too shy or depressed or whatever to come out of his shell. Once he got over whatever was holding him back, he started rolling.

 

[Agent Intellect]

I'd propose that you could make two personalities for someone, one based on genetics and one that is developed based on upbringing and other environmental factors. A third could possibly even be added to account for psychological problems such as depression, anxiety, OCD etc.

I'd say cognitive functions are probably primarily genetic: the I vs E, N vs S, F vs T, and P vs J. These functions are based on the way the brain is 'wired' as determined by genetics.

Then another set of dichotomies compete with that, which are developed due to external factors, and are therefore more malleable. I might say these dichotomies are:

Shy vs Outgoing
Open vs Conservative
Sensitive vs Practical
Lazy vs Driven

These dichotomies are similar to the cognitive functions, but different. For instance, an extrovert can be shy. While they find energy in talking to others, they don't like large crowds. Someone who is 'open' could have been a person who grew up with very socially liberal, artistic type parents, so they've been brought up to appreciate novelty. There could be any number of ways they become this way, and there could be ways of getting over it, unlike the cognitive functions which is a persons automatic way of doing things.

These functions I've just come up with have a way of influencing the personality tests, which is what would cause much of the confusion often seen here, with people wanting everyone to 'type' them.

Anyway, I just thought of this now, so I haven't really fleshed out any details.

 

[Da Blob]

Pfft! Stuff and Nonsense...

The only manifestation of genetics as a variable in the formation of personality is the well documented phenomena of Temperament.

One forms a personality based upon choices made of adaptive techniques, decisions which over time can become values or habits of preference of how to solve problems, primarily of changes in a social context.

Humans have the ability to adapt to survive and prosper. If One's life depended on being an ESFj for an extended period of time, One would prefer to be an ESFJ rather than an INTPian. Personality is primarily a POV used to solve problems, an algorithm, like the OODA Loop or the Scientific Method

:smiley_emoticons_mr

 

[walfin]

I just discovered that I have become an INFP, or so it seems.

So it can't be fully genetic. One person whose personality type has changed is enough to disprove that.

 

[SpaceYeti]

It's also possible your readings were wrong due to your own lack of understanding yourself and/or biased answers.

 

[redbaron]

I'd propose that you could make two personalities for someone, one based on genetics and one that is developed based on upbringing and other environmental factors. A third could possibly even be added to account for psychological problems such as depression, anxiety, OCD etc.

I'd say cognitive functions are probably primarily genetic: the I vs E, N vs S, F vs T, and P vs J. These functions are based on the way the brain is 'wired' as determined by genetics.

Then another set of dichotomies compete with that, which are developed due to external factors, and are therefore more malleable. I might say these dichotomies are:

Shy vs Outgoing
Open vs Conservative
Sensitive vs Practical
Lazy vs Driven

These dichotomies are similar to the cognitive functions, but different. For instance, an extrovert can be shy. While they find energy in talking to others, they don't like large crowds. Someone who is 'open' could have been a person who grew up with very socially liberal, artistic type parents, so they've been brought up to appreciate novelty. There could be any number of ways they become this way, and there could be ways of getting over it, unlike the cognitive functions which is a persons automatic way of doing things.

These functions I've just come up with have a way of influencing the personality tests, which is what would cause much of the confusion often seen here, with people wanting everyone to 'type' them.

Anyway, I just thought of this now, so I haven't really fleshed out any details.

This actually makes a lot of sense.

I'm an outgoing, open, practical and driven INTP. I feel like my upbringing had a large effect on who I was and am now, and I can see how a different upbringing would change my temperament, but not my core personality and modus operandi.

Pretty insightful for something you just thought of, I've always felt like MBTI is a little too much about the outline and doesn't enough colour in between.

 

[The Introvert]

Phenotypic variation is the sum of genetic influence and environmental influence.

Spoiler

A more detailed understanding can be found here:

http://en.wikipedia.org/wiki/Heritability#Definition

From my understanding, the only difference between genetics and epigenetics is that the trait in question was developed through a mechanism other than a change in the DNA sequence.

This means that yes, traits that are not inherited can be (and by definition have to be) acquired through environmental factors. I believe there is more than enough evidence to support the claim that 'personality' - and I use that term lightly - is a trait that is influenced by both genetics and epigenetics. Your mention of twin studies is one of many instances of such evidence.