Sex beyond the genitalia: The human brain mosaic

Sex/gender differences in the brain are of high social interest because their presence is typically assumed to prove that humans belong to two distinct categories not only in terms of their genitalia, and thus justify differential treatment of males and females. Here we show that, although there are sex/gender differences in brain and behavior, humans and human brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our results demonstrate that regardless of the cause of observed sex/gender differences in brain and behavior (nature or nurture), human brains cannot be categorized into two distinct classes: male brain/female brain.
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Whereas a categorical difference in the genitals has always been acknowledged, the question of how far these categories extend into human biology is still not resolved. Documented sex/gender differences in the brain are often taken as support of a sexually dimorphic view of human brains (“female brain” or “male brain”). However, such a distinction would be possible only if sex/gender differences in brain features were highly dimorphic (i.e., little overlap between the forms of these features in males and females) and internally consistent (i.e., a brain has only “male” or only “female” features). Here, analysis of MRIs of more than 1,400 human brains from four datasets reveals extensive overlap between the distributions of females and males for all gray matter, white matter, and connections assessed. Moreover, analyses of internal consistency reveal that brains with features that are consistently at one end of the “maleness-femaleness” continuum are rare. Rather, most brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our findings are robust across sample, age, type of MRI, and method of analysis. These findings are corroborated by a similar analysis of personality traits, attitudes, interests, and behaviors of more than 5,500 individuals, which reveals that internal consistency is extremely rare. Our study demonstrates that, although there are sex/gender differences in the brain, human brains do not belong to one of two distinct categories: male brain/female brain.

http://www.pnas.org/content/112/50/15468.full

Worth reading the full journal article.

>…“Sex/gender differences in the brain are of high social interest because their presence is typically assumed to prove that humans belong to two distinct categories not only in……/cut/….”

intro’s a bit weird, not that i’m averse to weird

dv said:

Sex beyond the genitalia: The human brain mosaic

Sex/gender differences in the brain are of high social interest because their presence is typically assumed to prove that humans belong to two distinct categories not only in terms of their genitalia, and thus justify differential treatment of males and females. Here we show that, although there are sex/gender differences in brain and behavior, humans and human brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our results demonstrate that regardless of the cause of observed sex/gender differences in brain and behavior (nature or nurture), human brains cannot be categorized into two distinct classes: male brain/female brain.
—
Whereas a categorical difference in the genitals has always been acknowledged, the question of how far these categories extend into human biology is still not resolved. Documented sex/gender differences in the brain are often taken as support of a sexually dimorphic view of human brains (“female brain” or “male brain”). However, such a distinction would be possible only if sex/gender differences in brain features were highly dimorphic (i.e., little overlap between the forms of these features in males and females) and internally consistent (i.e., a brain has only “male” or only “female” features). Here, analysis of MRIs of more than 1,400 human brains from four datasets reveals extensive overlap between the distributions of females and males for all gray matter, white matter, and connections assessed. Moreover, analyses of internal consistency reveal that brains with features that are consistently at one end of the “maleness-femaleness” continuum are rare. Rather, most brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our findings are robust across sample, age, type of MRI, and method of analysis. These findings are corroborated by a similar analysis of personality traits, attitudes, interests, and behaviors of more than 5,500 individuals, which reveals that internal consistency is extremely rare. Our study demonstrates that, although there are sex/gender differences in the brain, human brains do not belong to one of two distinct categories: male brain/female brain.

http://www.pnas.org/content/112/50/15468.full

Worth reading the full journal article.

I’ll try and find the time then.

Although it seems obvious to me that the spread of personality attributes across either gender is far greater than the difference between the median female and the median male, so talking of typical behaviours based on sex is just as bad as attributing typical behaviours based on race or ethnicity.

The Rev Dodgson said:

dv said:

Sex beyond the genitalia: The human brain mosaic

Sex/gender differences in the brain are of high social interest because their presence is typically assumed to prove that humans belong to two distinct categories not only in terms of their genitalia, and thus justify differential treatment of males and females. Here we show that, although there are sex/gender differences in brain and behavior, humans and human brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our results demonstrate that regardless of the cause of observed sex/gender differences in brain and behavior (nature or nurture), human brains cannot be categorized into two distinct classes: male brain/female brain.
—
Whereas a categorical difference in the genitals has always been acknowledged, the question of how far these categories extend into human biology is still not resolved. Documented sex/gender differences in the brain are often taken as support of a sexually dimorphic view of human brains (“female brain” or “male brain”). However, such a distinction would be possible only if sex/gender differences in brain features were highly dimorphic (i.e., little overlap between the forms of these features in males and females) and internally consistent (i.e., a brain has only “male” or only “female” features). Here, analysis of MRIs of more than 1,400 human brains from four datasets reveals extensive overlap between the distributions of females and males for all gray matter, white matter, and connections assessed. Moreover, analyses of internal consistency reveal that brains with features that are consistently at one end of the “maleness-femaleness” continuum are rare. Rather, most brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our findings are robust across sample, age, type of MRI, and method of analysis. These findings are corroborated by a similar analysis of personality traits, attitudes, interests, and behaviors of more than 5,500 individuals, which reveals that internal consistency is extremely rare. Our study demonstrates that, although there are sex/gender differences in the brain, human brains do not belong to one of two distinct categories: male brain/female brain.

http://www.pnas.org/content/112/50/15468.full

Worth reading the full journal article.

I’ll try and find the time then.

Although it seems obvious to me that the spread of personality attributes across either gender is far greater than the difference between the median female and the median male, so talking of typical behaviours based on sex is just as bad as attributing typical behaviours based on race or ethnicity.

Many things that should be obvious are not widely understood.

>Many things that should be obvious are not widely understood.

the more common an error too, the less effort that’s required to sustain it.

ideology makes good use of distortions about difference, and sameness

one thing that does strike me as requiring differences, is the reality that DNA recombination happens in ladies, ladies carry babies(gestation), give birth, and breast feed babies. Ladies also have miscarriages.

OK so they tested x females and x males… Were those people all cisgender?

transition said:

>
one thing that does strike me as requiring differences, is the reality that DNA recombination happens in ladies, ladies carry babies(gestation), give birth, and breast feed babies. Ladies also have miscarriages.

Some do, many don’t.

The Rev Dodgson said:

transition said:

>
one thing that does strike me as requiring differences, is the reality that DNA recombination happens in ladies, ladies carry babies(gestation), give birth, and breast feed babies. Ladies also have miscarriages.

Some do, many don’t.

I reckon you got the idea.

An article refuting this study can be found here:

https://www.psychologytoday.com/blog/sexual-personalities/201512/statistical-abracadabra-making-sex-differences-disappear

“….In contrast to the growing evidence of psychological sex differences, in a recent study Joel et al. (2015) examined sex differences in “personality traits, attitudes, interests, and behaviors” (as well as, brain features) and concluded, rather forcefully, that men and women are hardly different at all, arguing in the media that “there is no one person that has all the male characteristics and another person that has all the female characteristics” and consequently that we should give up entirely on using sex as a variable in sexual science.

“The Joel et al. (2015) study was certainly impressive, involving a remarkable collection of datasets across a wide variety of variables. Unfortunately, the specific techniques Joel et al. (2015) used for determining whether a sex difference is “real” were highly problematic. For instance, Joel et al. defined a sex difference as occurring only when it had “a high degree of internal consistency in the form of the different elements of a single brain (e.g., all elements have the “male” form).” (Joel et al., 2015, p. 1). That is, for a sex difference in the brain to “really” exist, men must have relatively masculine brains in each and every respect, and women must have relatively feminine brains in each and every respect. Otherwise, no sex difference. Really?”

esselte said:

An article refuting this study can be found here:

https://www.psychologytoday.com/blog/sexual-personalities/201512/statistical-abracadabra-making-sex-differences-disappear

“….In contrast to the growing evidence of psychological sex differences, in a recent study Joel et al. (2015) examined sex differences in “personality traits, attitudes, interests, and behaviors” (as well as, brain features) and concluded, rather forcefully, that men and women are hardly different at all, arguing in the media that “there is no one person that has all the male characteristics and another person that has all the female characteristics” and consequently that we should give up entirely on using sex as a variable in sexual science.

“The Joel et al. (2015) study was certainly impressive, involving a remarkable collection of datasets across a wide variety of variables. Unfortunately, the specific techniques Joel et al. (2015) used for determining whether a sex difference is “real” were highly problematic. For instance, Joel et al. defined a sex difference as occurring only when it had “a high degree of internal consistency in the form of the different elements of a single brain (e.g., all elements have the “male” form).” (Joel et al., 2015, p. 1). That is, for a sex difference in the brain to “really” exist, men must have relatively masculine brains in each and every respect, and women must have relatively feminine brains in each and every respect. Otherwise, no sex difference. Really?”

That mischaracterises the Joel paper. They did not state that men must have relatively masculine brains in each and every respect. Instead they quantitatively assessed the amount of overlap in multidimensional space, and it was too much to allow dichotomic characterization. We can example a person’s genitals and, with a very small number of exceptions, make a clear determination of whether they have male or female genitals, but we can’t do that with brains, they demonstrate.

esselte said:

An article refuting this study can be found here:

https://www.psychologytoday.com/blog/sexual-personalities/201512/statistical-abracadabra-making-sex-differences-disappear

“….In contrast to the growing evidence of psychological sex differences, in a recent study Joel et al. (2015) examined sex differences in “personality traits, attitudes, interests, and behaviors” (as well as, brain features) and concluded, rather forcefully, that men and women are hardly different at all, arguing in the media that “there is no one person that has all the male characteristics and another person that has all the female characteristics” and consequently that we should give up entirely on using sex as a variable in sexual science.

“The Joel et al. (2015) study was certainly impressive, involving a remarkable collection of datasets across a wide variety of variables. Unfortunately, the specific techniques Joel et al. (2015) used for determining whether a sex difference is “real” were highly problematic. For instance, Joel et al. defined a sex difference as occurring only when it had “a high degree of internal consistency in the form of the different elements of a single brain (e.g., all elements have the “male” form).” (Joel et al., 2015, p. 1). That is, for a sex difference in the brain to “really” exist, men must have relatively masculine brains in each and every respect, and women must have relatively feminine brains in each and every respect. Otherwise, no sex difference. Really?”

If you are dealing with very large groups then there may be some benefit in considering differences between average male and female behaviour, but in dealing with individuals it is highly counter-productive.

cf on average a man’s femur is longer than a woman’s but there’s no value at all in saying long femurs are male femurs and short femurs of female femurs.

https://www.youtube.com/watch?v=I1LI7ndOcGU

I tend to believe that dichotomies exist only in language, not fact. In support of this position, I present this argument: Any two things that you might identify as a dichotomous pair will have more in common with each other than either of them will have in common with any other thing.

The opposite of ‘boy’ is not ‘girl’ – it’s ‘house’, or ‘tree’, or ‘granite’, or perhaps, ‘whimsy’. Boys have more in common with girls than with any other thing.

dv said:

cf on average a man’s femur is longer than a woman’s but there’s no value at all in saying long femurs are male femurs and short femurs of female femurs.

This does not make it impossible to distinguish between a male femur and a female femur, though. There are other skeletal differences between men and women than bone length.

dv said:

cf on average a man’s femur is longer than a woman’s but there’s no value at all in saying long femurs are male femurs and short femurs of female femurs.

it won’t happen that specialists etc (in the various fields that need to) stop using bone structures to help indicate sex (male/female, of remains), and of the living there are reasons also for examining bone structures (related sex, of reproduction).

getting away from science for a moment, humans make observations of frame etc of others all the time. Male of females, females of males, females of females, males of males. Very young children do it quite instinctively, and blatantly.

Rule 303 said:

I tend to believe that dichotomies exist only in language, not fact. In support of this position, I present this argument: Any two things that you might identify as a dichotomous pair will have more in common with each other than either of them will have in common with any other thing.

The opposite of ‘boy’ is not ‘girl’ – it’s ‘house’, or ‘tree’, or ‘granite’, or perhaps, ‘whimsy’. Boys have more in common with girls than with any other thing.

I wouldn’t go that far. Some things have clearer divisions than others (eg, as I’ve mentioned, genitals). In some non-human animals there are clear sexual differences in coloration, for example, such that there is no significant overlap.

In humans, though, it’s just the uglies.

dv said:

Rule 303 said:

I tend to believe that dichotomies exist only in language, not fact.

(Squints) :)

Personally I don’t see that males and females are that different (their minds), they can’t be, all descended from equal males and females, and being human.

I think the cultural amplification of difference often causes distortions, and problems.

But then i’m wary of sexual egalitarianism too, for want of a better term. The imposition of, or egalitarianization that might repress differences. To think this can’t happen, like putting trousers on ladies, well, the possibility shouldn’t evaporate from our minds many of them may quite naturally prefer dresses and skirts, as do many men (on ladies, to be appreciated a man is a could-have-otherwise-been-a-woman, and vice versa – probably part of the attraction, nearest thing being is to have a partner of opposite sex).

on the subject dichotomies, the nurture/nature one for example, turns out viewing it as a dichotomy might have been largely crap.

It might be a bit of a weakness going to whatever is this, or that (of human behaviour, here), sometimes it’s better to perhaps more see whatevers’ flipside.

>as do many men (on ladies

There was little in the way of sex distinction in the wearing of trousers, skirts, tunics etc for most of the history of these garments.

Bubblecar said:

>as do many men (on ladies

There was little in the way of sex distinction in the wearing of trousers, skirts, tunics etc for most of the history of these garments.

neither does your typical sub/urban person (modern man) look out from their tiny patch of savanna and think africa.

IMO the basic difference between men and women is attitude, derived from the fundamental needs of the sexes. Men generally are the protectors, plus high protein provider, whilst women seek a man capable of providing these things, in order that she can produce children and create a home and family. Now I know there are many who will say, but that is not me, but when we were hunter/gatherers (some 95% of our existence) that is what we were and how we survived.

In modern times with birth control, education and the capacity of women to be completely self-supporting, it is much less important and so attitudes are changing and probably becoming more similar, which is basically evolution at work. Nevertheless, women do have different needs and desires to men and are generally the ones that cement a family together to make a home, which of course is in the male’s interest too.

Now the differences within the sexes will naturally vary considerably, but in the early days I suggest it would have been considerably less, as the chances of survival would have been greatly reduced. Basically we are animals and our needs are little different to those of other mammals, we however differ in the way we have evolved over the past 10,000 years due to farming, and especially recently permitting women to be more independent and pursue other interests and not be tied to a life of child rearing.

>…/cut/….pursue other interests and not be tied to a life of child rearing…./cut/….

It’s an interesting word “tied”, as you’ve used it.

_All adults will be tied to work and paying their bills_(speak that as a command from the aether, for affect). Probably most are.

And in many cases family is the other interest.

Bubblecar said:

>as do many men (on ladies

There was little in the way of sex distinction in the wearing of trousers, skirts, tunics etc for most of the history of these garments.

No true Scot wears trousers.

The Rev Dodgson said:

Bubblecar said:

>as do many men (on ladies

There was little in the way of sex distinction in the wearing of trousers, skirts, tunics etc for most of the history of these garments.

No true Scot wears trousers.

No True Scotsman phallacy.

This would appear to broadly support the OP -

Beyond sex differences: new approaches for thinking about variation in brain structure and function

Abstract

In the study of variation in brain structure and function that might relate to sex and gender, language matters because it frames our research questions and methods. In this article, we offer an approach to thinking about variation in brain structure and function that pulls us outside the sex differences formulation. We argue that the existence of differences between the brains of males and females does not unravel the relations between sex and the brain nor is it sufficient to characterize a population of brains. Such characterization is necessary for studying sex effects on the brain as well as for studying brain structure and function in general. Animal studies show that sex interacts with environmental, developmental and genetic factors to affect the brain. Studies of humans further suggest that human brains are better described as belonging to a single heterogeneous population rather than two distinct populations. We discuss the implications of these observations for studies of brain and behaviour in humans and in laboratory animals. We believe that studying sex effects in context and developing or adopting analytical methods that take into account the heterogeneity of the brain are crucial for the advancement of human health and well-being.