Research: testosterone changes brain structures in female-to-male transsexuals [pdf] | Hacker News Reader

Research: testosterone changes brain structures in female-to-male transsexuals [pdf]

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47 pointsno1ne46 comments

I mean sure, yeah, but...

https://hn.algolia.com/?query=changes%20brain&sort=byPopular...

so does meditation, walking in nature, inactivity, porn, drugs, focus, menstruation, Alzheimer's, cellphones, the iInternet, The Knowledge, programming, football...

changing it's structure is how the brain reacts to basically any regular stimulus. Thats how it works.

Agreed. Also, I've not read the paper yet, but I'll be very interested to see the effect size. Lots of sex differences neuroimaging papers rave about significance while ignoring the minuscule scale of effects.

Significance == publication, prestige, advancement

Effect power == bury it in the results, give it a one line 'yeah, we noticed that' in the discussion, so the publication reveiwer can't accuse you of missing something.

Indeed. It's all too tempting -- I've often found myself overlooking it a bit in my own work. When appropriate, I try to summarise key numbers, significance tests and effect sizes all in one table to avoid that problem.

And, perhaps more curiously, I don't see any discussion in the release about the possibility of or attempts to control for what else might be changing in the life of someone _beginning hormone therapy as part of a gender-transition process_.

How much of the change they observe is caused by testosterone, and how much is the expectation that one is becoming more masculine (and the downstream behavioral changes/feedback loop created if the self is _noticing_ changes that reinforce this expectation?) This isn't to say the effect they observe isn't real, but the conclusion they've reached doesn't seem to follow from the methodology discussed in the release.

I have MtF friend. We knew each other when we still we're both officially men. We became roommates for a year when she was mid transition.

I thought that would be cool, because I might understand women better now that I had somebody who had seen the both perspectives. How it is to be a man and how it is to be a woman.

I was wrong. She had never understood anything about manhood. Now she didn't even pretend anymore. I think there are some real and big differences between the sexes, but I still don't have good grasp about them.

Could you elaborate more? What are some of the differences she didn't understand?

I think the point vlehto is trying to make is:

He expected his friend, who he perceived as a "man", to have a particular kind of insight after the transition. Instead, he learned that his perception of the friend as a "man" was a projection. His friend would not have felt the need to transition if she felt she was a "man."

His friend could only provide more nuanced insights, because her experience was not that of a "man" becoming a "woman."

I think this explanation has the opposite effect: it cheapened the nuances of what he said.

abathur already got the gist of the subject.

If I asked her what women generally don't understand about men, she was unable to answer.

If I asked her what men don't understand about women, she replied with the standard feminist propaganda.

She had no special insight why women do things the way they do. (makeup, skirts, etc.) And she was unable to spot any non obvious differences between the sexes.

She's really not stupid. Just lacking perspective. Just like I am, but from different point of view.

I had a (male) colleague once argue with me that men and women had no differences in mentality due to testosterone. The desire to believe in equality is weird sometimes.

To be clear, I don't think there is any difference in generic mental abilities due to gender / sex, but it seems clear that brains would be affected by hormonal differences - for instance I have a thyroid deficiency, and I can really feel it when I'm low.

The way I see it is that, as often when it comes to differences due to sex, you have two wide Gaussian distributions that overlap a lot. Sure, there are behavioral differences (due to testosterone or other reasons), but the variation in behavior within one sex is probably larger than the distance between the means.

The problem is, that in casual speech, we can only easily express black-and-white: either men and women are different due to testosterone, or they are not. Neither statement is really correct.

With mental rotation, there is practically no overlap. See the graph from the original study.[1]

It's a similar story for physical strength. Nobody denies that men tend to be stronger than women, but most people vastly underestimate the disparity. In a study that measured grip strength in 2,000 people[2], the weakest 5% of men were comparable to the top decile of women. Even elite female athletes were only as strong as the median untrained male.

There are more examples (propensity for violence is another big one), but it takes time to find citations. Suffice it to say that most people think the sexes are more similar than they actually are.

1. https://brothersdiamond.files.wordpress.com/2015/02/menwoman... (For more on mental rotation and testosterone's effects, see my comment downthread: https://news.ycombinator.com/item?id=10443021)

2. http://egitim.judo.gov.tr/Dosyalar/makaleler/-ENG-Hand-grip-...

There's plenty of studies that debunk the mental rotation myth:

http://www.sciencedaily.com/releases/2010/09/100915080431.ht...

http://www.researchgate.net/profile/Angelica_Moe/publication...

There's also a study showing the field of neuroscience having a tendency to make unsupported and untested claims to confirm stereotypes http://link.springer.com/article/10.1007%2Fs12152-012-9169-1

http://www.northwestern.edu/newscenter/stories/2015/08/scien... Is this also stereotypical? Read what the researcher(a woman by the way)had to say. For 20 years, she actively avoided studying sex differences in the brain until her own data showed her that differences between females and males were real. Let science be about cold-hard facts and let it not be muddied by "feelings".

there's a pretty big difference between "debunk[ing] the ... myth" and showing the effect is real and can be reduced via training. in particular, your second link says the differences are probably real in its conclusion!

The myth is that the differences (in mental rotation ability) are innate or "biological", not that there is differences (in mental rotation ability) in the first place.

If one gender displays innate ability and the other can be trained to match it, then the difference is not shown to be a myth. There is a very dishonest redefinition of a common word involved to make the meaning apply.

Political fictions are comfortable but don't really change facts, they just color interpretations. Mischaracterizing observation does not serve to make an argument appear stronger.

Note that none of this means women are inferior, and if you are construing my point to mean I am arguing for that position, you have imposed that on me.

>> myth is that the differences are innate or "biological"

erm...please read

1. Genomic differences between developing male and female brains in the womb-- http://www.sciencedaily.com/releases/2015/02/150203190223.ht...

and if you still feel that somehow humans try to gender stereotype whilst the fetus are still in the wombs, then read this also-

2.Sex differences in rhesus monkey toy preferences parallel those of children-- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2583786/

I was referring to mental rotation ability, I clarified it in an edit.

I also don't have time to go into the studies you linked about general differences but similar studies have been debunked before. For example with 1.5 day old infants where the experimenters knew about the sex and their bias subtly corrupted the experiment and it did not reproduce when the bias was truly accounted for.

Often people want things to be 'equal', and often they don't really think about where that equality applies and what it really represents. I suspect many of them only want fairness but the inability to articulate that means they contort many statements into metaphysical absurdities to avoid having to be empathetic.

There are definitely differences in both generic mental abilities and what fields interest people between the sexes. From an evolutionary biology perspective, it would be really weird if there weren't.

To be clear, men and women are equally mentally gifted as a whole, but focused on different skills, and with bigger variance in men.

Pinker's "Blank Slate" lays out the case well: http://www.amazon.com/The-Blank-Slate-Modern-Denial/dp/15012...

You mean evolutionary psychology, not biology. The former is basically a pseudoscience and the latter makes no such claims.

I'm not even saying this is an established scientific claim, only that it would be really weird if the statistical differences between men and women were 100% outside of the brain, given how different the evolutionary pressures are.

Evolutionary psychology does have some problems :) It's easy to tell dazzling and believable stories in that frame, but much harder to prove them empirically.

I think some real science is being done in the field, but I agree that when people make EP arguments on the internet, you need to apply a lot of skepticism.

I've understood that while men are better at spatial reasoning, they are barely statistically better. And while women are better at language tasks, they are way better. So the conversation has always been slanted in that way.

Did your colleague know about mental rotation tests?[1] Men perform significantly better than women at these. And among men, mental rotation ability is correlated with testosterone levels.[2] I could see your buddy arguing that culture was responsible for behavioral differences such as violent tendencies, but the same dismissal can't be made of this test.

1. https://en.wikipedia.org/wiki/Mental_rotation

2. http://www.academia.edu/3118000/The_relationship_of_male_tes...

As esailija posted elsewhere in this thread, at least one study has shown that gender differences in mental rotation tasks can be eliminated through training.

In the "soft" sciences, about 1/3 of all studies get the wrong result.

This means you can always find a study supporting what you want to believe.

>Men perform significantly better

Actually, the reference you cited says "slightly better". It may or may not be significant but let's stay on track here.

In the original mental rotation test, there was no overlap between men and women: https://brothersdiamond.files.wordpress.com/2015/02/menwoman...

The Vandenberg and Kuse paper[1] followed up on this using a test that was easier to administer to large groups. In that study, the average male score was the same as the 85th percentile of female scores.

"Significant" describes this difference much more accurately than "slight."

1. http://wexler.free.fr/library/files/peters%20(1995)%20a%20re...

The male versus female is amazing, but what about that drop in ability from age 29 to 33. I know one of the video game FPS coaches said that after you turn 30, one is out of the game, but look at that drop. There should be studies to figure out what causes that; it is impacting male and female.

The drop is probably multiple factors, including aging. The study was done in 1975. Someone 28 years old would have been born in 1947. A 33 year-old would have been born in 1942 –the darkest days of WWII. Prenatal nutrition was likely an issue then. Ditto for those born earlier, as they had to deal with the great depression.

Also, the sample size in the first study was rather small, as they were just trying to answer the question, "Does the time it takes to mentally rotate an object depend on the angle of rotation?" (Answer: yes.)

> The desire to believe in equality is weird sometimes.

It's not that weird. If you look back in the HN archives, you can find one or two submissions from transsexual authors who argue, essentially, that after changing genders, they were discriminated against more, and that this proves that society/Silicon Valley/etc must be extremely sexist & discriminatory because nothing else about them changed; many of the HN commenters agreed with the claims.

>I had a (male) colleague once argue with me that men and women had no differences in mentality due to testosterone. The desire to believe in equality is weird sometimes.

Not to mention that there are lots of other differences that can have an impact, from the generally reduced physical strength, to birth related effects all the way down to increased life span...

It's unfortunate that changes in the brain is all they studied. If you have 18 people who are undergoing this transition, it would be useful to document any other changes and note them as candidates for further study.

For example, many people will remark on an increased sex drive (not a surprise considering the testosterone), but the way people actually think about and treat the opposite gender seems to change as well. It would suggest that testosterone has a part to play in the development of gendered social structures. But who knows?

> It's unfortunate that changes in the brain is all they studied. If you have 18 people who are undergoing this transition, it would be useful to document any other changes and note them as candidates for further study.

As a transman with a background in the sciences (social), I was actually really disappointed that there weren't any attempts to systematically gather this data when I was transitioning. I agree, it could bring a lot of data to the table that otherwise can't be ethically collected. Of course, in reporting any correlations there would need to be clear indications that the data came from the transexual community.

> many people will remark on an increased sex drive (not a surprise considering the testosterone)

Holy smokes! I was prepared for an increase, but I was totally not prepared for the amount of increase! I transitioned several years ago, and this change was definitely the one I was least prepared for.

> but the way people actually think about and treat the opposite gender seems to change as well.

Caveats galore: I don't think I treat the "opposite gender" any differently (to be clear, I was born in a female body, but identify as a guy, so "opposite gender" for me has always been women). But, I am very definitely treated differently BY many people, including women, now that I pass, i.e. I am seen as guy. As a result, I definitely treat individuals of the opposite gender differently because of how they treat me. For example, I can't stand women who complain about being discriminated against, but then clearly and unambiguously discriminate against me because I appear to be a privileged white guy. I simply couldn't judge this when I passed as a woman (I was aware that it happened, but without being a participant it's hard to determine whether that is in fact what's happening.) I now pass enough that I've experienced this with quite a few women. I've also dealt with more than a few women who are so hell bent on how they've been wronged, that they won't work with me because I'm a guy. The irony is that because I pass, when I'm in predominantly or exclusively male groups, I'm better able to argue for things which will reduce actual discrimination and bias against women.

You should see what it does to structure in utero!

Beautiful example of politics driving research. They only studied something they knew was a disadvantage for males, while the first thing everybody is curious about is how the IQ changed, if it changed: http://www.independent.co.uk/news/education/higher/dr-paul-i...

IIRC the higher variance in male IQ is hypothesised to be the result of men having only one X chromosome. I'd expect the null to hold in this case.

As @chroma pointed out, it would have been interesting to see if the mental rotation ability was improved, or if it is dependent on testosterone exposition during development.

It's a little weird to say males have higher IQ on average.

As I understand it (I'm not an IQ expert, just some internet know-it-all), women score better on some categories of questions, as do men, so when you put together a test, you try to make sure it balances out so both get the same average.

AFAIK the average is the same, but males have a higher variance, meaning that they are more likely to be found at the dumber and smarter ends of the population, while there are more women of average intelligence.

http://emilkirkegaard.dk/en/wp-content/uploads/Males-have-gr...

Wow, this is new to me... Please note, however, that this is an indirect measurement.

So reality is weird, but manipulating tests to ensure certain results is perfectly fine?

You seem argumentative.

In what brave new world is this a bad thing?

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