Sex personality differences

[lomiller]

The weakness of the correlation between brain size and the male/female dichotomy places a limit on how well you can distinguish male from female by looking at nothing other than brain size, but it most definitely does not mean you cannot do better than chance.


As noted in my previous post, it is possible to quantify this.

Start with the following facts.

• About 50% of the world's population is men, and 50% women.
• The distribution of brain sizes in men is approximated by a normal distribution.
• The distribution of brain sizes in women is approximated by a normal distribution.
• The mean brain size for men is approximately one standard deviation (of either distribution) greater than the mean brain size for women.

Using those facts, we can design the following crude algorithm that, given the size of a brain belonging to some person drawn at random from the world's population, guesses whether the brain belongs to a man or to a woman:

1. If the brain size is no greater than the mean brain size for women, guess that the brain belongs to a woman.
2. Otherwise guess that the brain belongs to a man.

Despite the obvious crudity (some might even say stupidity) of that algorithm, it performs better than chance. Roughly 16% of men's brains are no larger than the mean for women's brains, whereas 50% of women's brains are no larger than that threshold, so case 1 guesses right about 75% of the time (50/66). Roughly 84% of men's brains are larger than the mean for women's brains, whereas 50% of women's brains are larger than that threshold, so case 2 guesses right over 60% of the time (84/134). For brains drawn at random from the world's population, about 1/3 are handled by case 1 (half of (16% plus 50%)) and 2/3 by case 2, so the algorithm guesses right about

(75%/3 + (2 * 60%)/3) ≈ 65%​

of the time, which is better than chance. Despite its crudity, the algorithm is almost twice as likely to guess right as to guess wrong.

(An algorithm that splits the two cases at the intersection of the probability density functions for the two normal distributions would do slightly better, but its performance would be harder to explain to this audience.)

Ok but could the brain type identified by this technique be used to accurately predict:
a) the existence of feminine personality traits?
b) whether someone self identifies as transgender?

My guess is that it would not. If so this would mean that all you have is statistically expected error margins and not a tool that could help identify someone's gender.

 

[Darat]

I thought we were talking about science deniers, who some guy in quillete says social justice advocates. I prefer progressives, its a broader category and not so close to the now pejorative SJW.

-No not all

 

[theprestige]

It seems to me that if we stipulate that the findings are accurate, then:

- The social constructs of femininity correlate to distinct pattern of brain activity

- Therefore, the distinct pattern of brain activity can tell us when someone has really internalized the social constructs of femininity.

Which just tells us stuff we already knew about transgenderism, and doesn't really tell us anything about transsexualism.

Unless we're arguing that there is a biological justification for gender stereotypes as social constructs.

 

[ahhell]

You'd also need to account for the fact that "femininity" and "masculinity" are mostly social and cultural in nature with only a relatively small bias introduced by biological sex.

Isn't that the whole point of this conversation, for the most part we are really only guessing at how much of the difference between masculinity and femininity is biological vs sociological?

Just because the details vary from culture to culture, that doesn't mean there aren't actual differences.

 

[theprestige]

So the widespread claim that trans gender people and their supporters are "anti-science" seems to be based on this fundamental misunderstanding.

Is the claim widespread? What I see in The Other Thread is that trans activists are generally science opportunists (as are most of us, when we're not careful). They're more than happy to claim that the science is settled, and to cherry pick scientific research that supports their position. But they're also more than happy to ignore or dismiss scientific research that refutes or undermines their position. The ratio of claims that the science is settled to presentation of scientific evidence that supports such claims is also kind of depressing.

 

[W.D.Clinger]

Ok but could the brain type identified by this technique be used to accurately predict:
a) the existence of feminine personality traits?
b) whether someone self identifies as transgender?

My guess is that it would not.

That is my guess as well. (More than a guess, in fact.)

That's why I was careful to point out that the moderately weak correlation between brain size and the male/female dichotomy (a phrase I chose in some forlorn hope of avoiding arguments about sex vs gender) is nonetheless large enough so we could do better than chance in exactly the same way that we could use height or weight (as had been mentioned previously within this thread) to do better than chance.

If so this would mean that all you have is statistically expected error margins and not a tool that could help identify someone's gender.

So far as I know, no one has ever suggested brain size could be used as a tool to identify someone's gender (as opposed to the male/female dichotomy). Of course, a great many people have suggested a great many things of which I know nothing.

Once upon a time, thinking I might grow up to be a cognitive psychologist, I took some graduate courses and seminars and generally fell in with a bunch of actual cognitive psychologists, but hanging out with those people convinced me that psychology was too hard for me. One of the few things I learned is that most nature versus nurture controversies, or biological versus sociological, are based upon a gross oversimplification in which behavior is regarded as arising from some kind of linear combination of the two. That's nonsense. What matters, it seems to me, are the countless variety of ways in which the myriad aspects of nature can match up with the myriad aspects of nurture, and the bewildering complexity of behaviors that can result from those interactions.

That's pretty much why I decided psychology was too hard for me.

 

[ahhell]

From what I gather about the Claim in the Quillete piece is more along the lines of the Trans People are expressing a real biological thing and there fore, there must be a real biological difference between men an women. Big caveat there on my questionable understanding of the article.

Regarding Clingers post, soft sciences are called soft because not there easy but because its so hard to get firm conclusions.

Edited to add not.

 

[lomiller]

That is my guess as well. (More than a guess, in fact.)

That's why I was careful to point out that the moderately weak correlation between brain size and the male/female dichotomy (a phrase I chose in some forlorn hope of avoiding arguments about sex vs gender) is nonetheless large enough so we could do better than chance in exactly the same way that we could use height or weight (as had been mentioned previously within this thread) to do better than chance.


So far as I know, no one has ever suggested brain size could be used as a tool to identify someone's gender (as opposed to the male/female dichotomy). Of course, a great many people have suggested a great many things of which I know nothing.

Once upon a time, thinking I might grow up to be a cognitive psychologist, I took some graduate courses and seminars and generally fell in with a bunch of actual cognitive psychologists, but hanging out with those people convinced me that psychology was too hard for me. One of the few things I learned is that most nature versus nurture controversies, or biological versus sociological, are based upon a gross oversimplification in which behavior is regarded as arising from some kind of linear combination of the two. That's nonsense. What matters, it seems to me, are the countless variety of ways in which the myriad aspects of nature can match up with the myriad aspects of nurture, and the bewildering complexity of behaviors that can result from those interactions.

That's pretty much why I decided psychology was too hard for me.

Sorry I didn't mean to imply you had suggested we could arrive at a definition for a male\female brain that way, in fact I was pretty sure you were not. But when I re-read my response I realized it sounded more like a counterpoint to something you had said than an extension of it.

 

[Robin]

Is the claim widespread?

Widespread as in I hear it an awful lot, for example on Twitter, the comments section of Jerry Coyne's blog, Quillette, etc Not widespread in that it does tend to come from a particular tribe.

What I see in The Other Thread is that trans activists are generally science opportunists (as are most of us, when we're not careful). They're more than happy to claim that the science is settled, and to cherry pick scientific research that supports their position. But they're also more than happy to ignore or dismiss scientific research that refutes or undermines their position. The ratio of claims that the science is settled to presentation of scientific evidence that supports such claims is also kind of depressing.

I am seeing claims that the science showing a gendered brain is settled from the gender critical side, for example the author in the article I quote claims that anyone who says the brain is not gendered is anti-science, evolution-denying and comparable to creationists. The Quillette review of "The Gendered Brain" also claims that the science behind sex linked brain differences is settled.

Steve Pinker is a little more circumspect but sometimes writes as though the science showing the brain is gendered was settled.

I don't blame trans activists for believing that this science is settled since so many who are not trans activists, including some of their most vocal opponents, are saying the same thing on this particular point.

 

[Emily's Cat]

It isn't, but go on.

There is no third gamete in humans. There is no inbetween gamete in humans.

The existence of a subset of people with a genetic abnormality that results in them being born without legs does not make the number of legs on humans a spectrum, nor does it make humans magically not bipedal creatures.

Do NOT conflate people with disorders of sexual development with people who identify as transgender. They are not at all the same thing.

 

[Emily's Cat]

In modern humans, brain size provides a (weak) clue. In males, the average brain size is about 15% greater than in females. Thus brain size alone, like height alone or weight alone, is enough of a clue to distinguish male from female with accuracy slightly better than pure chance.

On the other hand... genitals have a 99.8% level of accuracy.

 

[theprestige]

Do NOT conflate people with disorders of sexual development with people who identify as transgender. They are not at all the same thing.

Indeed I'd be surprised if there was any overlap between the two groups at all. I suspect the number of people with sexual development disorders who also identify as transgender is infinitesimal.

 

[Emily's Cat]

What has been done is to look at the structure of brains and the evidence has been there is nothing structurally unique that allows one to identify a female from a male brain. All you can say is - to use an easier example to describe - is that "on average" males are taller than females so the taller folk in any given group are more likely to be male. But of course any given group may have short men and tall women in it, or may be all female or male. You can't use the "on average" property to identify whether any specific brain is female or male.

Brains are sexed, not gendered. So if you look at the chromosomal makeup of brain cells, you can tell which is male and which is female. Barring that, the only other observable difference is directly related to hormone exposure that differs between males and females.

As you say, all of the other claims to "man brain" and "lady brain" are inconclusive and not predictive.

 

[Emily's Cat]

But do you think that the behavioural and personality differences that exist on average between men and women are due to those things? That seems unlikely to me.

When people talk about "male brain" and "female brain" they are always talking about the hypothesised brain differences that underlie behavioral and personality differences observed between men and women.

So either there is some neural difference between men and women that underlies personality and behavioral differences and this is what we mean by "male brain" and "female brain", or else brains start more or less equal and the differences are due to culture and society in which case there is no such thing as a "male brain" and "female brain".
In neither case does the chromosomal difference you mention have any relevance.

The brains are chromosomally different between males and females. They are also subjected to hormones during fetal development, and those hormones differ between males and females. That hormone exposure results in some differences as I understand it, but those differences are directly sex-linked, and are almost entirely related to actual differences in sexual reproduction and sexual characteristics.

Brains are also highly plastic. Exposure throughout our lives to the differential conditioning of males and females has an affect on behavior and personality, which are reflected in brains.

But at the end of the day, there really isn't anything remotely akin to a "boy brain" and "girl" brain that supports the transgender rhetoric of "born in the wrong body". A transgender person's brain is not materially or statistically more like the sex that they identify with. A transgender person's brain is, however, materially and statistically more like the sex class to which they belong.

 

[Emily's Cat]

In fact I was unaware that there needed to be any argument that there is, in fact, such a thing as a transgender person.

Do some people here think that they are just making it all up?

That's a serious misinterpretation.

People exist who have gender dysphoria that is severe enough that they cannot become reconciled to their physical body. These people have traditionally been considered "transexxuals".

There are also people who exist who in some fashion "identify" as a different "gender" than the sex class to which their bodies belong. Those people certainly believe that they are transgender, and I doubt that they're all making it up, and I suppose that most of them aren't "making it up".

On the other hand, however, there is material reality. A person who identifies as a different gender than their biological sex may fully and 100% believe and express that perceived gender. But that in no way implies that they are, in actuality, materially similar to the opposite sex, or to no sex, or to an as-yet-unidentified other sex.

To put it very frankly... Transmen are not actually men. Transmen are women who wish to live their lives as if they were men.

 

[Emily's Cat]

But that doesn't let us make the conclusion that differences in behaviour are tied to those differences.

This reminds me of the early 90s research which claimed to have found a difference between homosexual men's brains and heterosexual men's brains and said the homosexual male's brain in this area was more like a heterosexual female's brain. That study failed to note that there was as much a variance within the brains of heterosexual males as between homosexual male and heterosexual males. In other words the exact same type of issue we have here, yes there are "on average" differences but the "spectrum of difference" is as large among brains of the same sex as between the different sexed brains. (The study was also of a small number of brains and had other methodological weaknesses.)

What would be required before we even start making any causal claims would be for very large studies that somehow determined "femininity" and "masculinity" of people and then scanned their brains. We could then look to see if there was any correlation between the more "female" brains and people scoring higher on the "femininity" score. If there was then we could extend that to trans folk and see if trans folk also show this correlation, then we could very tentatively consider that a trans person's brain matched the sex they feel they are.

Interestingly, I did read a thing not too long ago talking about this. It was specifically an area of the brain that governs sexual attraction and sexual posturing. They had been studying mice, I think, and had identified the area of the brain responsible for mating behavior and reproductive signaling. They found that if they exposed that region of the brain to different hormones during fetal development, a male mouse would exhibit the sexual behaviors of a female mouse when they attained reproductive maturity, and vice-versa. The article suggested that the same region of the brain exists in humans, and does pretty much the same function.

What I found most odd about it was that the article was suggesting that this region of the brain somehow was physical evidence of transgenderism. My interpretation was that it seemed like pretty clear-cut evidence of homosexuality.

 

[Emily's Cat]

From what I gather about the Claim in the Quillete piece is more along the lines of the Trans People are expressing a real biological thing and there fore, there must be a real biological difference between men an women. Big caveat there on my questionable understanding of the article.

Regarding Clingers post, soft sciences are called soft because not there easy but because its so hard to get firm conclusions.

Edited to add not.

That's... actually not at all what Colin Wright's article argues.

https://quillette.com/2018/11/30/the-new-evolution-deniers/

It's worth the read.

HEre are a couple of salient elements:

At first, left-wing pushback to evolution appeared largely in response to the field of human evolutionary psychology. Since Darwin, scientists have successfully applied evolutionary principles to understand the behavior of animals, often with regard to sex differences. However, when scientists began applying their knowledge of the evolutionary underpinnings of animal behavior to humans, the advancing universal acid began to threaten beliefs held sacrosanct by the Left. The group that most fervently opposed, and still opposes, evolutionary explanations for behavioral sex differences in humans were/are social justice activists. Evolutionary explanations for human behavior challenge their a priori commitment to “Blank Slate” psychology—the belief that male and female brains in humans start out identical and that all behavior, sex-linked or otherwise, is entirely the result of differences in socialization.

This stance is maintained by the belief that evolutionary explanations for sex-linked behavioral differences are biologically essentialist, which is the fatalistic notion that biology alone directly determines our behavior. Blank Slate psychology, however, is universally rejected by experts, as the evidence for innate sex-linked personality differences in humans is overwhelmingly strong. But experts also universally reject that this view demands we embrace biological essentialism, because the environment does play a role, and observed sex differences are simply averages and overlap tremendously between the sexes. Sex no more determines one’s personality than it determines one’s height. Sex certainly influences these traits, but it does not determine them. For instance, most of us know females who are taller than most males, and males who are shorter than most females, though we are all aware that males are, on average, taller than females. In humans, the same is true for behavioral traits.

Recently, this fear has been realized as social justice activists attempt to jump the epistemological shark by claiming that the very notion of biological sex, too, is a social construct.

As a biologist, it is hard to understand how anyone could believe something so outlandish. It’s a belief on a par with the belief in a flat Earth. I first saw this claim being made this year by anthropology graduate students on Facebook. At first I thought they mistyped and were simply referring to gender. But as I began to pay closer attention, it was clear that they were indeed talking about biological sex. Over the next several months it became apparent that this view was not isolated to this small friend circle, as it began cropping up all over the Internet. In support of this view, recent editorials from Scientific American—an ostensibly trustworthy, scientific, and apolitical online magazine—are often referenced. The titles read, “Sex Redefined: The Idea of 2 Sexes Is Overly Simplistic,” and “Visualizing Sex as a Spectrum.”

Even more recently, the most prestigious scientific journal in the world, Nature, published an editorial claiming that classifying people’s sex “on the basis of anatomy or genetics should be abandoned” and “has no basis in science” and that “the research and medical community now sees sex as more complex than male and female.” In the Nature article, the motive is stated clearly enough: acknowledging the reality of biological sex will “undermine efforts to reduce discrimination against transgender people and those who do not fall into the binary categories of male or female.” But while there is evidence for the fluidity of sex in many organisms, this is simply not the case in humans. We can acknowledge the existence of very rare cases in humans where sex is ambiguous, but this does not negate the reality that sex in humans is functionally binary. These editorials are nothing more than a form of politically motivated, scientific sophistry.

Despite the unquestionable reality of biological sex in humans, social justice and trans activists continue to push this belief, and respond with outrage when challenged. Pointing out any of the above facts is now considered synonymous with transphobia.

 

[theprestige]

What's the difference between a male with a male brain who thinks in measurably "feminine" ways but identifies as a man, and one who identifies as a woman? It's not like someone has to identify as a woman, just because they conform more closely to the social construct of womanhood. We're just circling back around - again - to the premise that transgenderism depends on perpetuating gender stereotypes.

For me, that's the most surreal thing here. I keep asking if there's any scientific evidence that there's something more to transgenderism than gender stereotypes. Instead, I get this, which appears to be scientific evidence that it's gender stereotypes all the way down.

So where does that leave us? Little Johnny says he's more comfortable thinking and acting the way girls typically think and act. And lo and behold! An examination of his brain confirms that in spite of his male chromosomes, he really does think that way. So what do we tell him? Do we tell him he really is a girl, and there's nothing wrong with that? What if he replies that he's a boy, he just likes girly things? Do we contradict him and prescribe transition therapy?

Do we tell him that's fine? That just because he likes girly things that doesn't mean he's a girl? In that case, what does mean he's a girl? Say he says he's a girl. Okay, that certainly means he's a girl. But then what does "being a girl" actually mean, other than "likes to think in girly ways"? Especially if thinking in girly ways is something boys can do too, without having to identify as girls.

What if the science of brains reveals that there are men who think more like typical* women, but are comfortable identifying as men, and there are also men who think more like typical women, but are uncomfortable identifying as men? What if science reveals that many men who identify as women don't think like typical women? Do we deny them the rights and accommodations due to transgender men? Do we deny that they're trans at all?

 

[W.D.Clinger]

The brains are chromosomally different between males and females. They are also subjected to hormones during fetal development, and those hormones differ between males and females. That hormone exposure results in some differences as I understand it, but those differences are directly sex-linked, and are almost entirely related to actual differences in sexual reproduction and sexual characteristics.

Some studies have suggested correlations between exposure in utero to hormones and differences that are not related to sexual reproduction or sexual characteristics.

They found that if they exposed that region of the brain to different hormones during fetal development, a male mouse would exhibit the sexual behaviors of a female mouse when they attained reproductive maturity, and vice-versa. The article suggested that the same region of the brain exists in humans, and does pretty much the same function.

It's worth noting that the human brain's development during in utero exposure to hormones is subject to variability caused by the specific mixture and intensity of hormones, the timing of that exposure during prenatal brain development, and even to the positioning of a fetus within the womb.

In short, it's complicated. As a result of that complexity, we should not expect to see a stark binary dichotomy between male and female brains, and we don't.

What I found most odd about it was that the article was suggesting that this region of the brain somehow was physical evidence of transgenderism. My interpretation was that it seemed like pretty clear-cut evidence of homosexuality.

Homosexuality is only one of the many adult traits/behaviors that some believe are linked to the timing and degree of in utero exposure to hormones.

 

[theprestige]

Seems like we're maybe less than a hundred years away from being able to engineer the sexuality of our children in utero. Which may raise some interesting ethical questions for our children to answer. I wonder what will happen when a hormonally-induced homosexual tells his parents that he never wanted to be gay, and he wishes he were straight, but that's not an option because his parents chose for him. Like those deaf parents who try to have deaf children by choice.

Anyone want to take a stab at the ethics of hormonally inducing gender dysphoria in the womb?