14 ms·

Greater male than female variability in regional brain structure (Paper)

79 points by vackosar 7y ago

RocketSyntax 7y ago
Females don't have chromosome Y, they have two chromosome X's. Therefore they don't get any Y stuff. And a mutation in one chromosome X can be mitigated by a non-mutation in the other chromosome X.
- prlambert 7y ago
  But they get two different X chromosomes with (hopefully) no correlation between them. Mutation interactions are complex.
  - RocketSyntax 7y ago
    Look into zygosity. Variants are either heterozygous or homozygous. A heterozygous variant is far less worse than a homozygous variant because the correct protein can still be produced to a certain extent.
- tveita 7y ago
  If this is a factor you should see the opposite pattern in birds.
  - chongli 7y ago
    That’s a great point. It may be very hard to see though. Male birds tend to be the ones with bright, showy plumage. They also tend to spend the most effort in courtship, with the Bowerbird [1] being the most extreme example. Since bright colours, elaborate songs, and other courtship displays tend to make male birds more vulnerable to predation, I would hypothesize that male birds also have greater trait variability due to all this risk taking. It would make for an interesting study anyway. [1] https://en.wikipedia.org/wiki/Bowerbird https://en.wikipedia.org/wiki/Bowerbird
    - SamReidHughes 7y ago
      It has been studied. Body size is more variable in female birds.
DaniFong 7y ago
measure this versus age in different cultures and we'll finally have some evidence on nurture versus nature. it's nurture + nature + serious amounts of work that makes extraordinary levels of talent; you can't get away with anything less. imho, schools and the popular culture cause brain damage, so who knows what the actual situation is. I know the article doesn't do this specifically, but since people will and do cite results like these as prescriptive facts which guide the people are waaay too complex and adaptable for helping us guide our lives. also interesting: explore similarities in background between structural brain outliers.
- rajansaini 7y ago
  Out of curiosity, what about schools and the popular culture do you think cause brain damage? What would your idea of an ideal education be?
  - marto1 7y ago
    Not OP, but how about we start from far away and not assume education is necessary. There is a strong correlation throughout human history between a discipline not being taken seriously and the same discipline growing by leaps and bounds. It is of course usually unintentionally or intentionally covered up by academics of various sorts. One major example is medicine - most of the ridiculously useful developments we got come from people experimenting and discovering without much formal constraints. Leonardo Da Vinci comes from a "guild of arts and medicine", the discovery of the nicotine patch came from the scientist almost killing himself with concentrated nicotine, incredible discoveries from WW1 till the end of WW2. Just my 2c.
    - lliamander 7y ago
      I would say that education is definitely necessary, but it need not take the shape of putting kids in desks for 6-8 hours a day for 12 years, nor need it involve a peer-dominated social environment entirely separate from the world of adults.
      - 7y ago
tossAfterUsing 7y ago
I thought everybody had exactly the same brain structure.
deleted 7y ago
[deleted]
lliamander 7y ago
That is a lot of authors on a paper. As a layman reading the paper, my understanding is that greater male variability has already been observed in "personality, coginitive abilities, and school achievement". The question here whether and to what extent that variability is due to "early life genetic or gene-environment interaction mechanisms". The implication of this paper seems to be that since pervasive brain-structure differences in variability can be observed throughout the lifespan of individuals, the variability in high-level traits are likely to have strong genetic component. The introduction in the paper focuses on the "downside" of high-variability in males (their propensity for neurological disorders). Unless I've missed it, any "upside" to high-variability was left unstated.
- lunias 7y ago
  Intuitively to me (I'm a layman as well) it seems that this male variability stems from increased competition amongst males. Historically, but certainly not necessarily, men have played the active role in society while women have been much more passive. It makes sense to me that without constant new stimuli, women have settled into a "best fit" position; while men are still rolling the dice (so to speak) looking for a big win.
  - Pyxl101 7y ago
    Point of consideration: supremely fit men in history (in a Darwinian sense) could have hundreds or thousands of children. Big wins can have big genetic payoffs. Supposedly Genghis Khan has millions of living descendants today, with perhaps as many as 1 in 200 men being direct descendants [1]. Supremely fit women can only have a limited number of children. This difference likely has some kind of effect on reproductive strategies, and what kinds of variation are selected for. [1] https://www.discovermagazine.com/the-sciences/1-in-200-men-direct-descendants-of-genghis-khan https://www.discovermagazine.com/the-sciences/1-in-200-men-d...
pubby 7y ago
Related theory: https://en.wikipedia.org/wiki/Variability_hypothesis https://en.wikipedia.org/wiki/Variability_hypothesis I first heard of this when researching chess. Men rank ~200 ELO points higher than women at chess, which is a fairly significant amount. Men also seem to do better at several other non-physical competitions like Go, video games, and Jeopardy. Plus, the history of math and science is dominated by men at the top. It seems like men are not smarter on average, but they do peak higher (and valley lower).
- aantix 7y ago
  How do these studies control for social encouragement?
  - mjfl 7y ago
    you could run a female cohort that is subject to nonstop social encouragement "you are powerful. you belong." and then observe whether they reach the same levels of achievement. If they do not, then this is evidence that the achievement is not due to social encouragement. You could alternatively look at the negative manifestations of variability, like increase crime and violence, and try to socially discourage it. Expose males to "crime is bad. bad men go to prison where they cannot have sex with women for many years. if you do crime you are bad." Observe whether crime rate of men relative to women decreases. If it does not, it is evidence that social encouragement is not responsible for the difference in crime. You could also do a control where you discouraged men from achieving. "Nerds are gross" and see if that leads to a victory for feminism.
    - szemet 7y ago
      Has already been done in the Polgar family, e.g.: https://en.wikipedia.org/wiki/Judit_Polg%C3%A1r https://en.wikipedia.org/wiki/Judit_Polg%C3%A1r The article has some quotations about Judits opinion: "I always say that women should have the self-confidence that they are as good as male players, but only if they are willing to work and take it seriously as much as male players." and after a tournsment in 1988 (12yo) "These other girls are not serious about chess...I practice five or six hours a day, but they get distracted by cooking and work around the house."
jmpman 7y ago
A president of Harvard, Lawrence Summers, was forced to step down after a 2005 speech in which he suggested that the under-representation of women in science and engineering could be due to a "different availability of aptitude at the high end". Could this regional brain structure account for the higher variance in male intelligence?
- octokatt 7y ago
  May I suggest you read the paper before (re)commenting this trope?
  - booboolayla 7y ago
    I'd love to see a real scientific paper validating the patriarchy theory, too.
  - gizmo686 7y ago
    What part of the paper are you refering to? The paper assumes a prior of males having greater variance in a diverse set of traits, and frames itself as exploring the cause of such variance. It proceeds to empirically study brain structure, and found that "results confirmed the hypothesis of greater male variability in brain structure.". Parent's question, while relevent, is much broader than what the paper attampted to answer. I see no discussion in the paper that would render the question moot.
    - octokatt 7y ago
      Correct. The question OP asked is much broader than what the paper's subject matter, and does not support evidence for the conjecture. Instead of asking again "maybe men just outcompete women because they have an inherent advantage", can we please just not do this. Again. It's become really disheartening to see this question being asked, because of a long history of infantilizing women and misusing science to prove it. Even if we're talking about population-level differences. I'm asking for empathy here, because every time a gender study comes up, it seems like someone again needs to ask if women really deserve an equal role at the table, as historical leaders or scientists, as part of humanity.

79 points by vackosar 7y ago

Females don't have chromosome Y, they have two chromosome X's. Therefore they don't get any Y stuff. And a mutation in one chromosome X can be mitigated by a non-mutation in the other chromosome X.

prlambert 7y ago
But they get two different X chromosomes with (hopefully) no correlation between them. Mutation interactions are complex.
- RocketSyntax 7y ago
  Look into zygosity. Variants are either heterozygous or homozygous. A heterozygous variant is far less worse than a homozygous variant because the correct protein can still be produced to a certain extent.
tveita 7y ago
If this is a factor you should see the opposite pattern in birds.
- chongli 7y ago
  That’s a great point. It may be very hard to see though. Male birds tend to be the ones with bright, showy plumage. They also tend to spend the most effort in courtship, with the Bowerbird [1] being the most extreme example. Since bright colours, elaborate songs, and other courtship displays tend to make male birds more vulnerable to predation, I would hypothesize that male birds also have greater trait variability due to all this risk taking. It would make for an interesting study anyway. [1] https://en.wikipedia.org/wiki/Bowerbird https://en.wikipedia.org/wiki/Bowerbird
  - SamReidHughes 7y ago
    It has been studied. Body size is more variable in female birds.

DaniFong 7y ago

measure this versus age in different cultures and we'll finally have some evidence on nurture versus nature. it's nurture + nature + serious amounts of work that makes extraordinary levels of talent; you can't get away with anything less. imho, schools and the popular culture cause brain damage, so who knows what the actual situation is. I know the article doesn't do this specifically, but since people will and do cite results like these as prescriptive facts which guide the people are waaay too complex and adaptable for helping us guide our lives. also interesting: explore similarities in background between structural brain outliers.

rajansaini 7y ago
Out of curiosity, what about schools and the popular culture do you think cause brain damage? What would your idea of an ideal education be?
- marto1 7y ago
  Not OP, but how about we start from far away and not assume education is necessary. There is a strong correlation throughout human history between a discipline not being taken seriously and the same discipline growing by leaps and bounds. It is of course usually unintentionally or intentionally covered up by academics of various sorts. One major example is medicine - most of the ridiculously useful developments we got come from people experimenting and discovering without much formal constraints. Leonardo Da Vinci comes from a "guild of arts and medicine", the discovery of the nicotine patch came from the scientist almost killing himself with concentrated nicotine, incredible discoveries from WW1 till the end of WW2. Just my 2c.
  - lliamander 7y ago
    I would say that education is definitely necessary, but it need not take the shape of putting kids in desks for 6-8 hours a day for 12 years, nor need it involve a peer-dominated social environment entirely separate from the world of adults.
    - 7y ago

tossAfterUsing 7y ago

I thought everybody had exactly the same brain structure.

deleted 7y ago

[deleted]

lliamander 7y ago

That is a lot of authors on a paper. As a layman reading the paper, my understanding is that greater male variability has already been observed in "personality, coginitive abilities, and school achievement". The question here whether and to what extent that variability is due to "early life genetic or gene-environment interaction mechanisms". The implication of this paper seems to be that since pervasive brain-structure differences in variability can be observed throughout the lifespan of individuals, the variability in high-level traits are likely to have strong genetic component. The introduction in the paper focuses on the "downside" of high-variability in males (their propensity for neurological disorders). Unless I've missed it, any "upside" to high-variability was left unstated.

lunias 7y ago
Intuitively to me (I'm a layman as well) it seems that this male variability stems from increased competition amongst males. Historically, but certainly not necessarily, men have played the active role in society while women have been much more passive. It makes sense to me that without constant new stimuli, women have settled into a "best fit" position; while men are still rolling the dice (so to speak) looking for a big win.
- Pyxl101 7y ago
  Point of consideration: supremely fit men in history (in a Darwinian sense) could have hundreds or thousands of children. Big wins can have big genetic payoffs. Supposedly Genghis Khan has millions of living descendants today, with perhaps as many as 1 in 200 men being direct descendants [1]. Supremely fit women can only have a limited number of children. This difference likely has some kind of effect on reproductive strategies, and what kinds of variation are selected for. [1] https://www.discovermagazine.com/the-sciences/1-in-200-men-direct-descendants-of-genghis-khan https://www.discovermagazine.com/the-sciences/1-in-200-men-d...

pubby 7y ago

Related theory: https://en.wikipedia.org/wiki/Variability_hypothesis https://en.wikipedia.org/wiki/Variability_hypothesis I first heard of this when researching chess. Men rank ~200 ELO points higher than women at chess, which is a fairly significant amount. Men also seem to do better at several other non-physical competitions like Go, video games, and Jeopardy. Plus, the history of math and science is dominated by men at the top. It seems like men are not smarter on average, but they do peak higher (and valley lower).

aantix 7y ago
How do these studies control for social encouragement?
- mjfl 7y ago
  you could run a female cohort that is subject to nonstop social encouragement "you are powerful. you belong." and then observe whether they reach the same levels of achievement. If they do not, then this is evidence that the achievement is not due to social encouragement. You could alternatively look at the negative manifestations of variability, like increase crime and violence, and try to socially discourage it. Expose males to "crime is bad. bad men go to prison where they cannot have sex with women for many years. if you do crime you are bad." Observe whether crime rate of men relative to women decreases. If it does not, it is evidence that social encouragement is not responsible for the difference in crime. You could also do a control where you discouraged men from achieving. "Nerds are gross" and see if that leads to a victory for feminism.
  - szemet 7y ago
    Has already been done in the Polgar family, e.g.: https://en.wikipedia.org/wiki/Judit_Polg%C3%A1r https://en.wikipedia.org/wiki/Judit_Polg%C3%A1r The article has some quotations about Judits opinion: "I always say that women should have the self-confidence that they are as good as male players, but only if they are willing to work and take it seriously as much as male players." and after a tournsment in 1988 (12yo) "These other girls are not serious about chess...I practice five or six hours a day, but they get distracted by cooking and work around the house."

jmpman 7y ago

A president of Harvard, Lawrence Summers, was forced to step down after a 2005 speech in which he suggested that the under-representation of women in science and engineering could be due to a "different availability of aptitude at the high end". Could this regional brain structure account for the higher variance in male intelligence?

octokatt 7y ago
May I suggest you read the paper before (re)commenting this trope?
- booboolayla 7y ago
  I'd love to see a real scientific paper validating the patriarchy theory, too.
- gizmo686 7y ago
  What part of the paper are you refering to? The paper assumes a prior of males having greater variance in a diverse set of traits, and frames itself as exploring the cause of such variance. It proceeds to empirically study brain structure, and found that "results confirmed the hypothesis of greater male variability in brain structure.". Parent's question, while relevent, is much broader than what the paper attampted to answer. I see no discussion in the paper that would render the question moot.
  - octokatt 7y ago
    Correct. The question OP asked is much broader than what the paper's subject matter, and does not support evidence for the conjecture. Instead of asking again "maybe men just outcompete women because they have an inherent advantage", can we please just not do this. Again. It's become really disheartening to see this question being asked, because of a long history of infantilizing women and misusing science to prove it. Even if we're talking about population-level differences. I'm asking for empathy here, because every time a gender study comes up, it seems like someone again needs to ask if women really deserve an equal role at the table, as historical leaders or scientists, as part of humanity.