Greater male than female variability in regional brain structure (Paper)(biorxiv.org)
biorxiv.org
Greater male than female variability in regional brain structure (Paper)
https://www.biorxiv.org/content/10.1101/2020.02.17.952010v1
53 comments
> and valley lower
Yeah - there are also a lot more men than women in prison.
Yeah - there are also a lot more men than women in prison.
Surely that is more due to testosterone than stupidity.
Modern research says no.
There has been a lot of research on this topic. You can not measure the testosterone in a group and make a prediction about who is going to commit a crime. If you measure testosterone on criminals, you can't make any prediction about what kind of crime they did.
There are weak associations such as risk taking (possible facilitated through increased dopamine transmitters), but there are much stronger links between criminals. To mention a few: Social economical status, social support structure, and childhood trauma is much better predictors than high testosterone.
Hormones are a terrible explanation for crime, even if they often have a weak association. Did you know that women are much more likely to have committed a crime during pms? The crime statistics support the link, but ask a researcher and they will list multiple reason why such correlation make for very weak association rather than strong evidence of a link between hormones and crime.
There has been a lot of research on this topic. You can not measure the testosterone in a group and make a prediction about who is going to commit a crime. If you measure testosterone on criminals, you can't make any prediction about what kind of crime they did.
There are weak associations such as risk taking (possible facilitated through increased dopamine transmitters), but there are much stronger links between criminals. To mention a few: Social economical status, social support structure, and childhood trauma is much better predictors than high testosterone.
Hormones are a terrible explanation for crime, even if they often have a weak association. Did you know that women are much more likely to have committed a crime during pms? The crime statistics support the link, but ask a researcher and they will list multiple reason why such correlation make for very weak association rather than strong evidence of a link between hormones and crime.
> You can not measure the testosterone in a group and make a prediction about who is going to commit a crime.
Well, if the group is mixed, with both men and women, then you can predict that 95% of the violent crimes will be committed by people with higher testosterone (i.e. men). Surely in that sense it's about testosterone, not genitalia?.
That's why it's very surprising to hear that the _level_ of testosterone among men has no predictive power.
Well, if the group is mixed, with both men and women, then you can predict that 95% of the violent crimes will be committed by people with higher testosterone (i.e. men). Surely in that sense it's about testosterone, not genitalia?.
That's why it's very surprising to hear that the _level_ of testosterone among men has no predictive power.
Nope, higher testosterone is not an predicting factor for violent crimes. If you measure a mixed group what you get is the same correlation as you would get with any other sex trait.
Many research papers has been written on the topic of testosterone and violence, including meta studies. The general conclusions is... there is a weak link between testosterone and violence. No cause and effect, but there is a small amplification of existing behavior, a common finding among endogenous studies.
The full reason is complex, but a simplification is that testosterone increase preexisting behavior in relation to social status hierarchy. It makes individuals spend more energy in defending their place on the ladder (spending more time looking at faces to recognize threat, increased response to threatening faces, more suspicion against ambiguous faces). This in turn has a link towards violence, but only in cultures where status is given as an reward for violence.
But there is an additional complexity that should be mentioned. A lot of the effects of hormones such as testosterone only happen as a result of changing levels of hormones rather than absolute values. The absolute value has less of a predictive effect then changes over a short time frame.
Many research papers has been written on the topic of testosterone and violence, including meta studies. The general conclusions is... there is a weak link between testosterone and violence. No cause and effect, but there is a small amplification of existing behavior, a common finding among endogenous studies.
The full reason is complex, but a simplification is that testosterone increase preexisting behavior in relation to social status hierarchy. It makes individuals spend more energy in defending their place on the ladder (spending more time looking at faces to recognize threat, increased response to threatening faces, more suspicion against ambiguous faces). This in turn has a link towards violence, but only in cultures where status is given as an reward for violence.
But there is an additional complexity that should be mentioned. A lot of the effects of hormones such as testosterone only happen as a result of changing levels of hormones rather than absolute values. The absolute value has less of a predictive effect then changes over a short time frame.
Interesting. So, my understanding is that most male violence is committed by males between the ages of 15 and 25 (roughly). That is also generally the period of highest testosterone levels in men. What would cause the spike in violence if not the elevated testosterone levels?
I have a couple guesses:
1. This may be a period in which men experience the greatest status uncertainty and so may resort to violence in an attempt to solidify their place in a social hierarchy.
2. This is generally the age range during which many disorders that are more prevalent or severe in men (such as schizophrenia, bi-polar, etc.) begin to manifest.
I have a couple guesses:
1. This may be a period in which men experience the greatest status uncertainty and so may resort to violence in an attempt to solidify their place in a social hierarchy.
2. This is generally the age range during which many disorders that are more prevalent or severe in men (such as schizophrenia, bi-polar, etc.) begin to manifest.
15 to roughly 25 is the period when the frontal cortex is maturing, and also the period where peer influence has the most impact on development. The frontal cortex is highly involved in silencing the fear response, and in determining the socially correct response to threats, particularly threats towards a person's social position (a common theme for studies around violence).
1) I have not read any study however that looked at periods of social uncertainty, but it sounds plausible.
2) My guess would go towards the relation of frontal cortex maturation. Before fully maturation, other parts of the brain "step in" and handle some of the frontal cortex' role, but by around age 25 they stop doing that.
1) I have not read any study however that looked at periods of social uncertainty, but it sounds plausible.
2) My guess would go towards the relation of frontal cortex maturation. Before fully maturation, other parts of the brain "step in" and handle some of the frontal cortex' role, but by around age 25 they stop doing that.
> My guess would go towards the relation of frontal cortex maturation. Before fully maturation, other parts of the brain "step in" and handle some of the frontal cortex' role, but by around age 25 they stop doing that.
So, do you mean that such disorders originate from the frontal cortex, and that the reason they manifest by 25 or so is because it is at that point that the frontal cortex is no longer "supported" by other parts of the brain and it's flaws become apparent? Interesting if so.
So, do you mean that such disorders originate from the frontal cortex, and that the reason they manifest by 25 or so is because it is at that point that the frontal cortex is no longer "supported" by other parts of the brain and it's flaws become apparent? Interesting if so.
Of course it’s an excellent predictor in a MIXED group. Testosterone predicts BEING male or not and being male predicts violent crime, almost perfectly.
testosterone certainly has a big impact, but the prison population also tends to have a much lower IQ average than the general population, and also tends have much higher rates of psychiatric disorders (schizophrenia, etc.).
Testosterone also leads to risk taking. Stupid risks and smart ones. Testosterone plus intelligence may be why there are more male cofounders/CEO's...
Arguably testosterone can lead to stupid decisions.
Who says testosterone is not related to stupidity? ;)
How do these studies control for social encouragement?
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.
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.
Has already been done in the Polgar family, e.g.:
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."
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."
>Has already been done in the Polgar family,
Well, no, it hasn't, because whatever the one family does can't change society at large and the messages/treatment women receive from it. The quotes you provide are examples of that.
Well, no, it hasn't, because whatever the one family does can't change society at large and the messages/treatment women receive from it. The quotes you provide are examples of that.
But you can't do this because you can't isolate people from society at large.
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?
Could this regional brain structure account for the higher variance in male intelligence?
May I suggest you read the paper before (re)commenting this trope?
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.
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.
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.
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.
“For many traits, males show greater variability than females” - first sentence in the paper’s abstract.
What “many traits” do you think are being referenced?
I’ve worked with many female engineers who are unquestionably smarter than I am. I’m married to one. Of course we are talking population-level differences, and I’m not suggesting that women shouldn’t be included in any table based upon meritocracy.
That doesn’t negate the fact that a president of Harvard was forced to step down for having a hypothesis that there could possibly be a gender difference explained by variance. Now that his hypothesis has a glimmer of possibly being supported by research, again, it continues to be vilified.
I’m asking for a world where a scientist can freely propose a hypothesis and not be forced to step down. Anything else is driving the anti-enlightenment.
Lawrence Summers is the Galileo of our time.
What “many traits” do you think are being referenced?
I’ve worked with many female engineers who are unquestionably smarter than I am. I’m married to one. Of course we are talking population-level differences, and I’m not suggesting that women shouldn’t be included in any table based upon meritocracy.
That doesn’t negate the fact that a president of Harvard was forced to step down for having a hypothesis that there could possibly be a gender difference explained by variance. Now that his hypothesis has a glimmer of possibly being supported by research, again, it continues to be vilified.
I’m asking for a world where a scientist can freely propose a hypothesis and not be forced to step down. Anything else is driving the anti-enlightenment.
Lawrence Summers is the Galileo of our time.
1. Summers is not a neuroscientist. He is an economist, and he is ill equipped to make any meaningful claims about this.
2. Proposing a hypothesis is not doing science. Science would involve actually testing a hypothesis by applying rigorous and reliable methods that suit the phenomenon being investigated, verifying the validity of results, interpreting the results and having the results reviewed by peer experts.
3. Summers’ remarks were merely pulled out of his ass and we’re in no way informed by any scientific process.
4. He has crucially undermined the work of countless women working as scientists at Harvard, and therefore failed in his duties as leader of that world class institution.
4. He resigned as a result of a no-confidence vote from the faculty (i.e. all the smart people who work at Harvard), which underscores how shitty he was at his job and how dumb his remarks were.
> Lawrence Summers is the Galileo of our time.
5. lol
2. Proposing a hypothesis is not doing science. Science would involve actually testing a hypothesis by applying rigorous and reliable methods that suit the phenomenon being investigated, verifying the validity of results, interpreting the results and having the results reviewed by peer experts.
3. Summers’ remarks were merely pulled out of his ass and we’re in no way informed by any scientific process.
4. He has crucially undermined the work of countless women working as scientists at Harvard, and therefore failed in his duties as leader of that world class institution.
4. He resigned as a result of a no-confidence vote from the faculty (i.e. all the smart people who work at Harvard), which underscores how shitty he was at his job and how dumb his remarks were.
> Lawrence Summers is the Galileo of our time.
5. lol
You can take any amount of scientific evidence that there are population level differences and there will still be someone who will discard it like it does not matter at all.
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.
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.
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.
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-d...
[1] https://www.discovermagazine.com/the-sciences/1-in-200-men-d...
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.
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.
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?
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.
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.
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.
Well, the main purpose of school is to socialise children and prepare them for spending 8 hours a day behind a desk doing things that they often don't find very interesting. So schools seem pretty apt preparation for real life.
Socialization is good, but that doesn't mean the way schools provide it is optimal. A peer-dominated social environment all too often results in a Lord of the Flies scenario of children playing petty power games. And when the only interaction with adults is as impersonal authority figures, children are left unprepared for the world of adult interaction.
Something I've seen actually work really well for socialization is homeschooling, where children are exposed both to children of a variety of ages (younger and older) and the interactions with adults are more personable. They also more often get to see adults interacting with each other as adults.
I suspect there is probably a profound benefit to children who have adult figures in their own lives (aside from their parents) that they can look up to as a models of successful behavior - as opposed to merely having pop culture and other kids to model themselves after.
Something I've seen actually work really well for socialization is homeschooling, where children are exposed both to children of a variety of ages (younger and older) and the interactions with adults are more personable. They also more often get to see adults interacting with each other as adults.
I suspect there is probably a profound benefit to children who have adult figures in their own lives (aside from their parents) that they can look up to as a models of successful behavior - as opposed to merely having pop culture and other kids to model themselves after.
Few things in this world are optimal... But homeschooling seems very suboptimal for socialization purposes, just meeting your family all the time seems like an extremely bad idea. Or what did you have in mind?
Most homeschooled children don't just meet with their own family all the time.
Say you have the typical dad-works-and-mom-stays-home setup. Mom's got to go to the grocery store? Kids go, too, and practice their arithmetic in real-world environments. They also interact with at least the cashier, and probably a number of other adults.
It's a nice day? They go to the park, and look at wildlife and plants. Along the way, they interact with a number of other people at the park. And so it goes. They interact with non-family-members all over the place.
But if that's not enough for socialization, well... when we got concerned about socialization, we grabbed the kids, dragged them into the bathroom, and beat them up for their lunch money. You know, so that they got socialized the way that public school kids did.
Say you have the typical dad-works-and-mom-stays-home setup. Mom's got to go to the grocery store? Kids go, too, and practice their arithmetic in real-world environments. They also interact with at least the cashier, and probably a number of other adults.
It's a nice day? They go to the park, and look at wildlife and plants. Along the way, they interact with a number of other people at the park. And so it goes. They interact with non-family-members all over the place.
But if that's not enough for socialization, well... when we got concerned about socialization, we grabbed the kids, dragged them into the bathroom, and beat them up for their lunch money. You know, so that they got socialized the way that public school kids did.
> But if that's not enough for socialization, well... when we got concerned about socialization, we grabbed the kids, dragged them into the bathroom, and beat them up for their lunch money. You know, so that they got socialized the way that public school kids did.
We just put ours in a drab room with an uncomfortable chair and a video of an adult droning on for several hours.
We just put ours in a drab room with an uncomfortable chair and a video of an adult droning on for several hours.
That still sounds like 95% of their interactions will be with family members?
From what I've seen, homeschooling is typically done in a communal fashion. Home is just the base of operations, but schooling and socialization happens all over the place. Things like community sports, church, scouts, homeschooling associations, etc. all provide a way for children to interact with other children and adults in a variety of contexts.
I went through public/government schools the whole way through, and my experience was fairly positive overall. However, having now met many adults who were homeschooled, and participating in the homeschool scene as a parent, I'm fairly convinced that homeschooling results in more mature, more prepared individuals.
Obviously, some kids will be overly cloistered and may be hurt socially by that, but that doesn't seem to be the norm. Besides, plenty of kids come out of government schools pretty messed up as it is.
I went through public/government schools the whole way through, and my experience was fairly positive overall. However, having now met many adults who were homeschooled, and participating in the homeschool scene as a parent, I'm fairly convinced that homeschooling results in more mature, more prepared individuals.
Obviously, some kids will be overly cloistered and may be hurt socially by that, but that doesn't seem to be the norm. Besides, plenty of kids come out of government schools pretty messed up as it is.
> There is a strong correlation throughout human history between a discipline not being taken seriously and the same discipline growing by leaps and bounds.
There’s arguably a stronger trend between work that’s not taken seriously and work that is not meaningful, rigorous or grounded on solid foundations. Bad research is typically ignored because it is recognized to be poorly conceived. Most scraps left behind really are scraps.
There’s arguably a stronger trend between work that’s not taken seriously and work that is not meaningful, rigorous or grounded on solid foundations. Bad research is typically ignored because it is recognized to be poorly conceived. Most scraps left behind really are scraps.
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I thought everybody had exactly the same brain structure.
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.
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.
But they get two different X chromosomes with (hopefully) no correlation between them. Mutation interactions are complex.
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.
If this is a factor you should see the opposite pattern in birds.
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
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
It has been studied. Body size is more variable in female birds.
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).