Sex personality differences

[Robin]

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?

 

[Robin]

The correlations are weak. Without additional information, you have no way of knowing whether the brain you're looking out is simply a particularly large woman's brain or a particularly small man's brain. The ranges overlap too much.

But you wouldn't just look at one characteristics. You would look at a number of the ways in which a male brain is hypothesised to differ from a female brain in order to make the determination.

The question is, if you took neuroimaging dumps from 100 brains, gave them to someone without anything that identifies the person and asked them to determine "male" or "female" and then check this against the sex as identified at the chromosomal level, would they match better than chance?

The evidence appears to be that, yes, they would match better than chance.

 

[Puppycow]

My own theory is that the brains of men and women are largely the same, and that the differences we observe in personalities, behavior and so on between men and women are largely due to differences in sex hormones.

Although scientists may not be able to find significant structural differences between male and female brains, they can easily find significant differences in hormones between men and women. The hormones affect personality. This is confirmed also by the experiences of people who take cross-sex hormones. Particularly female-to-male transitioners have reported significant differences in their feelings after they start to take testosterone.

I don't think it makes sense to talk about sex personality differences without considering the effect of hormones.

 

[Darat]

But you wouldn't just look at one characteristics. You would look at a number of the ways in which a male brain is hypothesised to differ from a female brain in order to make the determination.

The question is, if you took neuroimaging dumps from 100 brains, gave them to someone without anything that identifies the person and asked them to determine "male" or "female" and then check this against the sex as identified at the chromosomal level, would they match better than chance?

The evidence appears to be that, yes, they would match better than chance.

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.

 

[Darat]

My own theory is that the brains of men and women are largely the same, and that the differences we observe in personalities, behavior and so on between men and women are largely due to differences in sex hormones.

Although scientists may not be able to find significant structural differences between male and female brains, they can easily find significant differences in hormones between men and women. The hormones affect personality. This is confirmed also by the experiences of people who take cross-sex hormones. Particularly female-to-male transitioners have reported significant differences in their feelings after they start to take testosterone.

I don't think it makes sense to talk about sex personality differences without considering the effect of hormones.

I agree and I'd also say we have a problem with determining whether the egg or chicken came first given the plasticity of the brain, we know our behaviour can shape our brains, which in turn can shape our behaviour.

 

[W.D.Clinger]

The correlations are weak.

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.

Without additional information, you have no way of knowing whether the brain you're looking out is simply a particularly large woman's brain or a particularly small man's brain. The ranges overlap too much.

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.)

 

[Robin]

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

No, and I didn't say it did. In fact I am pretty sure that I have earlier remarked that any physical differences in the brain that underlie differences in behaviour and personality would probably be much subtler than things like brain size.

 

[Darat]

No, and I didn't say it did. In fact I am pretty sure that I have earlier remarked that any physical differences in the brain that underlie differences in behaviour and personality would probably be much subtler than things like brain size.

I've not been using brain size as a metric - W.D.Clinger is only using that as a simple example to explain how we can identify brains as coming from males or females better than chance.

It is the structure, to the degree we can now "scan" of the brains is what we are discussing, and we don't (yet? Or never?) find differences that correlate with our sex that allows a determination of the sex of any specific brain sans examination of chromosomes or genitals/generative organs.

Give the "structural" differences we see between the male and female physiology in other areas of our make-up I find it quite surprising we can't find such clear differences in the structure of female and male brains. But that is what our current evidence points to.

 

[Roger Ramjets]

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.

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

Using those facts, we can design the following crude algorithm that, given the size of a brain belonging to some bigot drawn at random from the world's population, guesses whether the brain belongs to a man or a man (they are almost always men).

 

[theprestige]

So you think that tall women are really men?

I think that women with men's legs follows directly from your argument for women with mens' brains.

I think that transitioning based on having a statistically differently-sexed brain makes as much sense as transitioning based on having a statistically differently-sexed pair of legs.

Or are you saying that there is no average difference between the heights of men and woment?

If you think neither of these things then your point does not follow.

Playing dumb doesn't help your argument.

I am? News to me. Perhaps you have mixed me up with someone else.

That's how I read this:

So the idea that someone might be born in the wrong body is consistent with such scientific evidence as long as we understand it as someone having the brain characteristics that are usually associated with the people who have the opposite sexual characteristics.

 

[theprestige]

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?

I'm sure some of them are.

But the real issue is that there needs to be an argument that transgenderism is a specific kind of thing that requires specific accommodations in public policy.

If someone says "I should compete in women's sports leagues because I am actually a woman in a man's body", there needs to be an argument that a woman in a man's body is a real thing, and that the proposed solution is the right solution for people in that situation.

I don't think there needs to be any argument that there is, in fact, such a thing as people who suffer from body integrity identity disorder (BIID). But I do think there absolutely needs to be an argument for why amputating their limbs until they're happy with their body is the right course of treatment for that condition.

 

[ahhell]

I predict: Nothing good can come of this thread.

Something good can come of this thread. Admittedly there is a significant chance that it won't.

This is true but I'll try too.

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.

The spoiler is for anyone who wants context but I'm interested in responding to the unspoiled bit. It would make humans rather special if genetic sexual dimorphism was only limited to physical characteristics and genetics had no impact on the behavioral sexual dimorphism.

My perception of the progressives understanding of sex and gender is that its a bit split. There seems to be believe among some that gender is immutable and thus Trans folks makes sense on account their gender which can not be changed is different from their biological sex. There also seems to be a belief among progressive that the behavioral differences between genders are mostly or entirely cultural. That venn diagram may have no over lap but from the outside it looks like it has a lot of overlap. It seems like there are folks that believe that gender is both a social construct and immutable.

That being said, there do seem to be a lot of progressives that seem to believe in the blank slate idea of human nature and to deny a significant impact of genetics on behavior. I think they believe this because if genetics to have significant impact on human behavior then some of their goals may be difficult to achieve. It could also be used to support some fairly reactionary policies. Some folks might use genetic differences as a reason to discriminate against women or ethnic groups.

 

[ahhell]

Honestly, its pretty simple. Its pretty difficult to parse what the impacts of nature vs nurture are on behavior. The folks that research these things with twin studies and what not, seem to think that culture amounts to about 30% of the differences.

When it comes to gender, there are two bell curves for pretty much every way you can measure physical and behavioral differences. One for human females and one for human males. They over lap more than they don't. To me it seems like conservatives often want to pretend there's no overlap and progressives want to pretend there's no difference in distribution.

Take IQ, my recollection is that on average women have a higher IQ than men but that the bell curve for men is flatter, so more men have very high and very low IQs. Does that matter? Probably not for the vast majority of people but it almost certainly matters for things like winning nobel prizes or criminality.

 

[Darat]

No idea who these "progressives" are meant to be - I thought we were discussing the science?

 

[ahhell]

I have also heard an interview with one person who basically denies the impact of Testosterone. Which seems to be country to just about everything I've ever read or heard on the subject.

 

[ahhell]

No idea who these "progressives" are meant to be - I thought we were discussing the science?

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.

 

[ahhell]

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.

I don't see how that follows, if there is a neural difference, what causes it? Possibly environment, possibly genetics, possibly the combination of both.

 

[lomiller]

Not so, as in my earlier example. You can construct the groups "adult" and "child" in any way you want, for example you can make the cut-off at 16 years of age or 18 years of age or any other cut off you like.

Puberty brings on significant set of biological changes that marks childhood as a distantly different state than adulthood. For practical considerations we often have little choice but to approximate by setting age limits. These age cut-offs can and frequently do lead to contractions and artifacts near the cut-off point.

The main thing is that childhood and adulthood are very different readily discernable biological states so the division isn't arbitrary. There is a big difference between using independent parameters to define a group and searching for parameters that correspond to a grouping you want to define. The latter.

 

[lomiller]

But you wouldn't just look at one characteristics. You would look at a number of the ways in which a male brain is hypothesised to differ from a female brain in order to make the determination.

The question is, if you took neuroimaging dumps from 100 brains, gave them to someone without anything that identifies the person and asked them to determine "male" or "female" and then check this against the sex as identified at the chromosomal level, would they match better than chance?

The evidence appears to be that, yes, they would match better than chance.

Probabaly not. A personality questionnaire may do a slightly better job but it would be sensitive to social and cultural context. Furthermore, in the vast majority of cases such a test misidentified the biological sex of the subject, the subject themselves would not identify themselves as transgender.

 

[lomiller]

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.

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.