6 ms·

> 50% of personality from genetics What's the source of this? Given that siblings are often so different between each other, and from their parents, it could b

by tomp 8y ago

> 50% of personality from genetics What's the source of this? Given that siblings are often so different between each other, and from their parents, it could be that most of personality traits come from the environment, but we're still born with it (i.e. it could be influence in early development of the fetus, from the environment (womb, food mother eats and her hormones, sounds and movement from outside, ...) not from genes).

afpx 8y ago
“... Pinker relies on a 1998 book called "The Nurture Assumption," by Judith Rich Harris, which has been the object of some controversy in the field of developmental psychology. Harris claimed that "shared family environments"—that is, parents—have little or no effect on a child's personality.” https://www.newyorker.com/magazine/2002/11/25/what-comes-naturally-2 https://www.newyorker.com/magazine/2002/11/25/what-comes-nat... As a parent, that seems about right. We may lay a foundation for helping them make good choices. But, a child’s identity ultimately seems to be formed by their predisposition and the types of peers that they seek out and befriend at around 12 years and onwards.
- DanBC 8y ago
  We're not going to get any useful information from a pop sci book that uses other pop sci books as sources. There's almost no fact checking and they usually mangle the science. http://www.danielbor.com/lehrerandsciencewriting/ http://www.danielbor.com/lehrerandsciencewriting/ http://www.slate.com/articles/health_and_science/science/2016/08/why_doesn_t_anyone_fact_check_science_books.html?via=gdpr-consent http://www.slate.com/articles/health_and_science/science/201...
  - afpx 8y ago
    Sorry, I would have cited specific chapters and paragraphs if I had more time. I don’t even know where my copy of the book is, at the moment (somewhere around here). I figured a ‘pop sci’ reference could at least help guide the way. My bad.
    - rusk 8y ago
      I think there's an emerging etiquette around this kind discourse that where "research" conflicts with personal experiences that attempts be made to cross-check and reconcile that. These days with all the bad science around we have to be a lot more careful about what we accept as fact.
      - emodendroket 8y ago
        A pop-sci book seems like it's at least as good as personal anecdote, which is used on HN to claim all sorts of bizarre things.
        rusk 8y ago
        I would rate personal anecdote higher. Pop-sci often adopts sensationalism at the expense of rigour in order to shift volumes. At least personal, lived experience can be taken at face value, if accepted in good faith as a truthful account, and can be cross-examined.
        emodendroket 8y ago
        I'd say the opposite, because pop-science books at least represent an effort to collate multiple examples in support of some thesis and do not exclusively rely on the experiences of one individual. Of course we can see this used maliciously all the time (I think people are finally starting to turn on Malcolm Gladwell), but to me that just suggests both are fairly low-quality sources.
        rusk 8y ago
        Except, you can't deny personal experience. The onus on science is to explain experience, not the other way round. If you have an observer giving a truthful account that conflicts with an established fact then surely something must account for that discrepancy. See for instance radio-waves vs Kirchoffs law. It's not that Kirchoff was wrong, it's just that he didn't account for frequency as a variable, which was solved by Maxwell. Now, that's for established facts. If you're talking about commercially adulterated science then you have an even higher burden to bear.
rusk 8y ago
> influence in early development of the fetus, ... womb, food mother eats and her hormones, sounds and movement from outside I actually do think this counts for a lot. Certainly there are genetic and epigenetic factors, but scant attention is paid to gestative influence (an area it seems few know much about). It does seem there is an eagerness to label all personality traits from the date-of-birth as "genetic".
grandpa 8y ago
You could test this by looking at whether pairs of fraternal twins are as similar on personality traits as pairs of identical twins. If they are more different, then genes are the cause.
- rusk 8y ago
  There's been lots of these twin studies. Most of what we know about genetic influences has been determined this way. https://en.wikipedia.org/wiki/Twin_study https://en.wikipedia.org/wiki/Twin_study
- callesgg 8y ago
  You cant objectively measure the difference between two people.
barry-cotter 8y ago
http://humancond.org/papers/turkheimer00_three_laws_behavior_genetics http://humancond.org/papers/turkheimer00_three_laws_behavior... The author proposes three laws of behavioral genetics which summarize results across a wide range of behaviors: All human behavioral traits are heritable. The effect of being raised in the same family is smaller than the effect of genes. A substantial portion of the variation in complex human behavioral traits is not accounted for by the effects of genes or families.
naasking 8y ago
> Given that siblings are often so different between each other But most identical twins are not so different from each other. Read up on twin studies, where twins were separated at birth. They tend to have very similar personalities and outlooks on life, despite never having had contact until the study was conducted.
- tomp 8y ago
  That still wouldn't separate genetics vs. common pre-birth environmental influences (e.g. mother's hormones and nutrition).
  - TheOtherHobbes 8y ago
    There's not much known because it's almost impossible to research, surely? You'd have to have one identical twin developing naturally, and the other brought to term inside a surrogate mother. This probably doesn't happen very often. (TBH I don't know if it's even possible.)
  - naasking 8y ago
    > That still wouldn't separate genetics vs. common pre-birth environmental influences (e.g. mother's hormones and nutrition). Sure it would, if you study enough of them.
- lurquer 8y ago
  That isn't sufficient, unfortunately. A third-party's treatment of an individual depends a lot on the appearance of the individual. (i.e., beautiful people are treated differently than ugly people.) That is, one's appearance can have a causal effect on one's 'environment.' Thus, even if raised separately, the 'environment' to which each identical twin is exposed will be more similar than the 'environments' of two non-identical people. Simple example.... Adam and Bob are raised separately. Yet, both develop to be confident and strong leaders. Is this leadership quality 'genetic'? Or, is it because Adam and Bob are each 6'5" and handsome? It would be very difficult indeed to statistically tease out these things.
wenc 8y ago
> What's the source of this? Yes, I wonder about this too. > Given that siblings are often so different between each other, and from their parents, it could be that most of personality traits come from the environment, but we're still born with it. In terms of genetics, the reason there's variation between siblings and parents, even though it is true that as children we inherit 50% of our genes from our father and 50% from our mother, is due to randomness in terms of which parts get inherited. Our siblings are inherits different combinations of genetics, but we all inherit 50%/50%. This doesn't answer the question of how much of our personality is inherited vs environmental, but that siblings/parents are so different from each other doesn't argue against heritability.

by tomp 8y ago

afpx 8y ago

“... Pinker relies on a 1998 book called "The Nurture Assumption," by Judith Rich Harris, which has been the object of some controversy in the field of developmental psychology. Harris claimed that "shared family environments"—that is, parents—have little or no effect on a child's personality.” https://www.newyorker.com/magazine/2002/11/25/what-comes-naturally-2 https://www.newyorker.com/magazine/2002/11/25/what-comes-nat... As a parent, that seems about right. We may lay a foundation for helping them make good choices. But, a child’s identity ultimately seems to be formed by their predisposition and the types of peers that they seek out and befriend at around 12 years and onwards.

DanBC 8y ago
We're not going to get any useful information from a pop sci book that uses other pop sci books as sources. There's almost no fact checking and they usually mangle the science. http://www.danielbor.com/lehrerandsciencewriting/ http://www.danielbor.com/lehrerandsciencewriting/ http://www.slate.com/articles/health_and_science/science/2016/08/why_doesn_t_anyone_fact_check_science_books.html?via=gdpr-consent http://www.slate.com/articles/health_and_science/science/201...
- afpx 8y ago
  Sorry, I would have cited specific chapters and paragraphs if I had more time. I don’t even know where my copy of the book is, at the moment (somewhere around here). I figured a ‘pop sci’ reference could at least help guide the way. My bad.
  - rusk 8y ago
    I think there's an emerging etiquette around this kind discourse that where "research" conflicts with personal experiences that attempts be made to cross-check and reconcile that. These days with all the bad science around we have to be a lot more careful about what we accept as fact.
    - emodendroket 8y ago
      A pop-sci book seems like it's at least as good as personal anecdote, which is used on HN to claim all sorts of bizarre things.
      - rusk 8y ago
        I would rate personal anecdote higher. Pop-sci often adopts sensationalism at the expense of rigour in order to shift volumes. At least personal, lived experience can be taken at face value, if accepted in good faith as a truthful account, and can be cross-examined.
        emodendroket 8y ago
        I'd say the opposite, because pop-science books at least represent an effort to collate multiple examples in support of some thesis and do not exclusively rely on the experiences of one individual. Of course we can see this used maliciously all the time (I think people are finally starting to turn on Malcolm Gladwell), but to me that just suggests both are fairly low-quality sources.
        rusk 8y ago
        Except, you can't deny personal experience. The onus on science is to explain experience, not the other way round. If you have an observer giving a truthful account that conflicts with an established fact then surely something must account for that discrepancy. See for instance radio-waves vs Kirchoffs law. It's not that Kirchoff was wrong, it's just that he didn't account for frequency as a variable, which was solved by Maxwell. Now, that's for established facts. If you're talking about commercially adulterated science then you have an even higher burden to bear.

rusk 8y ago

> influence in early development of the fetus, ... womb, food mother eats and her hormones, sounds and movement from outside I actually do think this counts for a lot. Certainly there are genetic and epigenetic factors, but scant attention is paid to gestative influence (an area it seems few know much about). It does seem there is an eagerness to label all personality traits from the date-of-birth as "genetic".

grandpa 8y ago

You could test this by looking at whether pairs of fraternal twins are as similar on personality traits as pairs of identical twins. If they are more different, then genes are the cause.

rusk 8y ago
There's been lots of these twin studies. Most of what we know about genetic influences has been determined this way. https://en.wikipedia.org/wiki/Twin_study https://en.wikipedia.org/wiki/Twin_study
callesgg 8y ago
You cant objectively measure the difference between two people.

barry-cotter 8y ago

http://humancond.org/papers/turkheimer00_three_laws_behavior_genetics http://humancond.org/papers/turkheimer00_three_laws_behavior... The author proposes three laws of behavioral genetics which summarize results across a wide range of behaviors: All human behavioral traits are heritable. The effect of being raised in the same family is smaller than the effect of genes. A substantial portion of the variation in complex human behavioral traits is not accounted for by the effects of genes or families.

naasking 8y ago

> Given that siblings are often so different between each other But most identical twins are not so different from each other. Read up on twin studies, where twins were separated at birth. They tend to have very similar personalities and outlooks on life, despite never having had contact until the study was conducted.

tomp 8y ago
That still wouldn't separate genetics vs. common pre-birth environmental influences (e.g. mother's hormones and nutrition).
- TheOtherHobbes 8y ago
  There's not much known because it's almost impossible to research, surely? You'd have to have one identical twin developing naturally, and the other brought to term inside a surrogate mother. This probably doesn't happen very often. (TBH I don't know if it's even possible.)
- naasking 8y ago
  > That still wouldn't separate genetics vs. common pre-birth environmental influences (e.g. mother's hormones and nutrition). Sure it would, if you study enough of them.
lurquer 8y ago
That isn't sufficient, unfortunately. A third-party's treatment of an individual depends a lot on the appearance of the individual. (i.e., beautiful people are treated differently than ugly people.) That is, one's appearance can have a causal effect on one's 'environment.' Thus, even if raised separately, the 'environment' to which each identical twin is exposed will be more similar than the 'environments' of two non-identical people. Simple example.... Adam and Bob are raised separately. Yet, both develop to be confident and strong leaders. Is this leadership quality 'genetic'? Or, is it because Adam and Bob are each 6'5" and handsome? It would be very difficult indeed to statistically tease out these things.

wenc 8y ago

> What's the source of this? Yes, I wonder about this too. > Given that siblings are often so different between each other, and from their parents, it could be that most of personality traits come from the environment, but we're still born with it. In terms of genetics, the reason there's variation between siblings and parents, even though it is true that as children we inherit 50% of our genes from our father and 50% from our mother, is due to randomness in terms of which parts get inherited. Our siblings are inherits different combinations of genetics, but we all inherit 50%/50%. This doesn't answer the question of how much of our personality is inherited vs environmental, but that siblings/parents are so different from each other doesn't argue against heritability.