6 ms·

Sex Differences in the Adult Human Brain

58 points by vixen99 8y ago

saagarjha 8y ago
Not really a fan of the title here…something about it just seems too editorialized. Maybe "significant mean differences found between mens' and womens' brains?"
a_bonobo 8y ago
Title using 'very large' does not come from the article, which gives a more subtle image: >Sex Differences in the Adult Human Brain: Evidence from 5216 UK Biobank Participants >Males had higher raw volumes, raw surface areas, and white matter fractional anisotropy; females had higher raw cortical thickness and higher white matter tract complexity. There was considerable distributional overlap between the sexes. Personally I wouldn't call the difference between a mean of 1115.76 with an standard deviation of 89.68 and a mean of 1233.58 with an SD of 98.31 very large (all in cm^3)
- lokopodium 8y ago
  This resolves to something like 70% males have larger brains than 70% females.
  - depressedpanda 8y ago
    Actually, the paper states: > The differences were substantial: in some cases, such as total brain volume, more than a standard deviation. The effect size of d = −1.41 for total brain volume (Table 1) translates to 92.1% of males being above the female mean, and an 84.1% chance that a randomly-chosen male will have a larger total brain volume than a randomly-chosen female.
    - zhdc1 8y ago
      The height of the average male (178cm) is more than one standard deviation (8.9cm) above the height of the average female (165.1cm). I don't really know if we should be surprised that the differences between male and female brain volumes are also statistically significant and larger than one standard deviation.
- Pilfer 8y ago
  The effect size is quite large. From the paper, The differences were substantial: in some cases, such as total brain volume, more than a standard deviation. The effect size of d = −1.41 for total brain volume (Table 1) translates to 92.1% of males being above the female mean, and an 84.1% chance that a randomly-chosen male will have a larger total brain volume than a randomly-chosen female.
- depressedpanda 8y ago
  TFA measures a lot more than mere total brain volume.
  - candiodari 8y ago
    Yeah, and let's just pretend that your implied argument, that looking at the other values measured finds that they, in toto, mean the brains are equal. Of course that's very far from the truth. It's funny: your statement is perfectly true, and yet gives completely wrong information ... you ever thought about taking up politics ? But no worries: the study did mention the forbidden metric of death : cognitive tests. First, an important note: the cognitive tests were specifically chosen to be tests where the mean between men and women would be the same, this is not a coincidence. It is known that there are tests where the mean is not the same between males and females. For example, males have a slight advantage in 3d reasoning skills and females have somewhat better temporal analysis skills ("males aim, females plan"). It shows the same as all others, by the way. Male brains are more experimental : more variable in nearly every way. The dumbest human alive is very likely male, and so is the smartest. Let's face facts here: the very basis for tolerance is, flat out, totally, and completely wrong. There are in fact sex differences, including in the brain and resulting ability. (worse: there are race differences too. aiaiai) Whether that means we should or should not practice tolerance is, of course, an unrelated question. But we should be able to answer it without falsifying and denying scientific results. There, I think every sacred egg, left and right, racist and tolerant, has been thoroughly stomped on. Can we now have an adult discussion ?
    - depressedpanda 8y ago
      It's funny: your post comes across like you're arguing against me, yet I actually agree with most of what you wrote. I think we should be able to acknowledge and accept our differences but also be tolerant of them.
    - dang 8y ago
      Arguing like this, crossing into personal nastiness while slinging rhetoric like weapons, will get you banned on HN, regardless of how right or wrong your or anyone else's views are. Please don't post like this again. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- mirimir 8y ago
  Yes, it's a superficially inflammatory title. This paragraph from the discussion is interesting: > An additional hypothesis—one that is not incompatible with the hypothesis that some of the sex differences seen here are a proximate cause of behavioral differences—is that brain structural differences might sometimes be the result of compensatory mechanisms for differences in sex-specific hormones, and might thus act to reduce behavioral sex differences that would otherwise have been present (De Vries 2004; McCarthy and Arnold 2011). This perspective may in part explain an apparent paradox in human sex difference research: that the (raw) effect sizes found for brain measures such as volume and surface area are so large, whereas most behavioral sex differences are so small (Hyde 2014). Our descriptive results do not directly speak to any causal mechanisms, but it should be borne in mind that they are compatible with these multiple interpretations.
- vixen99 8y ago
  Please note that 'very large' was indeed quoted directly from the paper. "The average difference for the 14 subcortical volumes was d = −0.70. A set of Bayesian t-tests (see Supplemental Materials and Table 1) confirmed that the mean sex differences were very large, with extremely strong evidence in favor of the hypothesis that males differed from females "on every overall and subcortical volume." You add that in your personal opinion the difference is 'not very large'. What should be the magnitude of the numbers below to fall into the 'large' category in your assessment? Quote: "...total brain volume translates to 92.1% of males being above the female mean and an 84% chance that a randomly-chosen male will have a large brain volume than a randomly chosen female" That's pretty significant in terms of means.
  - dang 8y ago
    Cherry-picking a phrase and making it the title is a form of editorializing, which breaks the HN guidelines. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html When the topic is divisive, doing this is particularly bad. It can easily ruin the thread for discussion. If you want to say what you think is important about an article, please do so in a comment. Then your view is on a level playing field with everyone else's.
- teilo 8y ago
  Not only that, there was significant overlap in the distributions.
Kenji 8y ago
Is saying such a thing allowed in the age of political correctness and equality?
venning 8y ago
Mods, perhaps "Sex Differences in the Adult Human Brain: Evidence from 5216 Participants" would be less editorialized while not overly long.
sanxiyn 8y ago
Of interest: There was generally greater male variance across the raw structural measures. They also cite Global Sex Differences in Test Score Variability (Science, 2008).
- venning 8y ago
  Towards the end of the Introduction, they have a paragraph where they discuss how the study intends to test the "greater male variability hypothesis", something I had not heard of before. They reference other studies which have show greater variability among males in: cognitive ability, academic achievement test results, personality, athletic performance, birth weight, and adult weight.
mg794613 8y ago
Uh-oh this is going to hurt a lot of people. Even if the article did not state anything about the actual effects of these differences. Just mentioning or hinting at this nowadays will result in a lot of automatic flack and backlash. Notice how the incoming comments will be about the title and not the contents and the subsequent derived meaning of this. They will probably have to change the title to not offend anyone. Sadly this is our current state of approach on science.
- pgsandstrom 8y ago
  So far two comments like yours, getting meta-offended by theoretical complaints. People getting upset from the actual result: Zero. Sadly this is our current state of approach on science.
  - larrykwg 8y ago
    the first reaction people had was to literally complain about the title, questioning the whole conclusion. I don't think he was too far off the mark
  - bryanrasmussen 8y ago
    The first comment I saw when I came in to the post start off: "Title using 'very large' does not come from the article, which gives a more subtle image:" which sounds to me like someone taking offense to the title?
    - jjk166 8y ago
      They're taking offense to the title being a mischaracterization of the paper, not to the result in the paper
      - bryanrasmussen 8y ago
        ok thanks.
      - sanxiyn 8y ago
dvfjsdhgfv 8y ago
The article itself is not so much interesting to me that the reactions to it on HN. The articles says nothing on how these differences translate into psychological traits/abilities etc. Nevertheless, even a hint that there might be differences, and that they're might be quite pronounced, somehow cannot be a subject of civilized discussion on HN and people will flag it straight away. Why? What are you afraid of? Understanding these results might help us to understand ourselves better. Or do you prefer not to have such research in the name of political correctness?
vixen99 8y ago
Why is a submission with an accurately worded title linking to a paper from top-ranking institutions contributed by 18 authors flagged on HN?
- usmanshaikh06 8y ago
  "liberals"
- flukus 8y ago
  HN only likes science when it has PC conclusions.
  - dang 8y ago
    Please don't post unsubstantive comments here. HN is divided on divisive issues. Anthropomorphizing it into something that "likes" what you dislike and "dislikes" what you like is just an illusion, but has become a rhetorical trick, as cheap as it is common. Please don't do that here.
- Yetanfou 8y ago
  For the same reason that Galilei and Copernicus came into conflict with the Roman Catholic church authorities, why Socrates was forced to drink poison for 'corrupting the youth': some ideas are not tolerated within certain societies no matter their scientific underpinning. In other words, those ideas go against the dogmata [1] of such societies. [1] https://en.wikipedia.org/wiki/Dogma https://en.wikipedia.org/wiki/Dogma
- dang 8y ago
  Because (a) you violated the site guidelines by editorializing the title (see https://news.ycombinator.com/item?id=17147115 https://news.ycombinator.com/item?id=17147115), and (b) to do that when the subject matter is divisive is flamebait, violating the guidelines in a second and worse way. HN's rules are the way they are for good reason. Please (re-)read and follow them from now on: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html. Threads are acutely sensitive to initial conditions. What you did made a very large increase in the probability that this discussion would be ruined before it began.

58 points by vixen99 8y ago

Not really a fan of the title here…something about it just seems too editorialized. Maybe "significant mean differences found between mens' and womens' brains?"

a_bonobo 8y ago

Title using 'very large' does not come from the article, which gives a more subtle image: >Sex Differences in the Adult Human Brain: Evidence from 5216 UK Biobank Participants >Males had higher raw volumes, raw surface areas, and white matter fractional anisotropy; females had higher raw cortical thickness and higher white matter tract complexity. There was considerable distributional overlap between the sexes. Personally I wouldn't call the difference between a mean of 1115.76 with an standard deviation of 89.68 and a mean of 1233.58 with an SD of 98.31 very large (all in cm^3)

lokopodium 8y ago
This resolves to something like 70% males have larger brains than 70% females.
- depressedpanda 8y ago
  Actually, the paper states: > The differences were substantial: in some cases, such as total brain volume, more than a standard deviation. The effect size of d = −1.41 for total brain volume (Table 1) translates to 92.1% of males being above the female mean, and an 84.1% chance that a randomly-chosen male will have a larger total brain volume than a randomly-chosen female.
  - zhdc1 8y ago
    The height of the average male (178cm) is more than one standard deviation (8.9cm) above the height of the average female (165.1cm). I don't really know if we should be surprised that the differences between male and female brain volumes are also statistically significant and larger than one standard deviation.
Pilfer 8y ago
The effect size is quite large. From the paper, The differences were substantial: in some cases, such as total brain volume, more than a standard deviation. The effect size of d = −1.41 for total brain volume (Table 1) translates to 92.1% of males being above the female mean, and an 84.1% chance that a randomly-chosen male will have a larger total brain volume than a randomly-chosen female.
depressedpanda 8y ago
TFA measures a lot more than mere total brain volume.
- candiodari 8y ago
  Yeah, and let's just pretend that your implied argument, that looking at the other values measured finds that they, in toto, mean the brains are equal. Of course that's very far from the truth. It's funny: your statement is perfectly true, and yet gives completely wrong information ... you ever thought about taking up politics ? But no worries: the study did mention the forbidden metric of death : cognitive tests. First, an important note: the cognitive tests were specifically chosen to be tests where the mean between men and women would be the same, this is not a coincidence. It is known that there are tests where the mean is not the same between males and females. For example, males have a slight advantage in 3d reasoning skills and females have somewhat better temporal analysis skills ("males aim, females plan"). It shows the same as all others, by the way. Male brains are more experimental : more variable in nearly every way. The dumbest human alive is very likely male, and so is the smartest. Let's face facts here: the very basis for tolerance is, flat out, totally, and completely wrong. There are in fact sex differences, including in the brain and resulting ability. (worse: there are race differences too. aiaiai) Whether that means we should or should not practice tolerance is, of course, an unrelated question. But we should be able to answer it without falsifying and denying scientific results. There, I think every sacred egg, left and right, racist and tolerant, has been thoroughly stomped on. Can we now have an adult discussion ?
  - depressedpanda 8y ago
    It's funny: your post comes across like you're arguing against me, yet I actually agree with most of what you wrote. I think we should be able to acknowledge and accept our differences but also be tolerant of them.
  - dang 8y ago
    Arguing like this, crossing into personal nastiness while slinging rhetoric like weapons, will get you banned on HN, regardless of how right or wrong your or anyone else's views are. Please don't post like this again. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
mirimir 8y ago
Yes, it's a superficially inflammatory title. This paragraph from the discussion is interesting: > An additional hypothesis—one that is not incompatible with the hypothesis that some of the sex differences seen here are a proximate cause of behavioral differences—is that brain structural differences might sometimes be the result of compensatory mechanisms for differences in sex-specific hormones, and might thus act to reduce behavioral sex differences that would otherwise have been present (De Vries 2004; McCarthy and Arnold 2011). This perspective may in part explain an apparent paradox in human sex difference research: that the (raw) effect sizes found for brain measures such as volume and surface area are so large, whereas most behavioral sex differences are so small (Hyde 2014). Our descriptive results do not directly speak to any causal mechanisms, but it should be borne in mind that they are compatible with these multiple interpretations.
vixen99 8y ago
Please note that 'very large' was indeed quoted directly from the paper. "The average difference for the 14 subcortical volumes was d = −0.70. A set of Bayesian t-tests (see Supplemental Materials and Table 1) confirmed that the mean sex differences were very large, with extremely strong evidence in favor of the hypothesis that males differed from females "on every overall and subcortical volume." You add that in your personal opinion the difference is 'not very large'. What should be the magnitude of the numbers below to fall into the 'large' category in your assessment? Quote: "...total brain volume translates to 92.1% of males being above the female mean and an 84% chance that a randomly-chosen male will have a large brain volume than a randomly chosen female" That's pretty significant in terms of means.
- dang 8y ago
  Cherry-picking a phrase and making it the title is a form of editorializing, which breaks the HN guidelines. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html When the topic is divisive, doing this is particularly bad. It can easily ruin the thread for discussion. If you want to say what you think is important about an article, please do so in a comment. Then your view is on a level playing field with everyone else's.
teilo 8y ago
Not only that, there was significant overlap in the distributions.

Kenji 8y ago

Is saying such a thing allowed in the age of political correctness and equality?

venning 8y ago

Mods, perhaps "Sex Differences in the Adult Human Brain: Evidence from 5216 Participants" would be less editorialized while not overly long.

sanxiyn 8y ago

Of interest: There was generally greater male variance across the raw structural measures. They also cite Global Sex Differences in Test Score Variability (Science, 2008).

venning 8y ago
Towards the end of the Introduction, they have a paragraph where they discuss how the study intends to test the "greater male variability hypothesis", something I had not heard of before. They reference other studies which have show greater variability among males in: cognitive ability, academic achievement test results, personality, athletic performance, birth weight, and adult weight.

mg794613 8y ago

Uh-oh this is going to hurt a lot of people. Even if the article did not state anything about the actual effects of these differences. Just mentioning or hinting at this nowadays will result in a lot of automatic flack and backlash. Notice how the incoming comments will be about the title and not the contents and the subsequent derived meaning of this. They will probably have to change the title to not offend anyone. Sadly this is our current state of approach on science.

pgsandstrom 8y ago
So far two comments like yours, getting meta-offended by theoretical complaints. People getting upset from the actual result: Zero. Sadly this is our current state of approach on science.
- larrykwg 8y ago
  the first reaction people had was to literally complain about the title, questioning the whole conclusion. I don't think he was too far off the mark
- bryanrasmussen 8y ago
  The first comment I saw when I came in to the post start off: "Title using 'very large' does not come from the article, which gives a more subtle image:" which sounds to me like someone taking offense to the title?
  - jjk166 8y ago
    They're taking offense to the title being a mischaracterization of the paper, not to the result in the paper
    - bryanrasmussen 8y ago
      ok thanks.
    - sanxiyn 8y ago

dvfjsdhgfv 8y ago

The article itself is not so much interesting to me that the reactions to it on HN. The articles says nothing on how these differences translate into psychological traits/abilities etc. Nevertheless, even a hint that there might be differences, and that they're might be quite pronounced, somehow cannot be a subject of civilized discussion on HN and people will flag it straight away. Why? What are you afraid of? Understanding these results might help us to understand ourselves better. Or do you prefer not to have such research in the name of political correctness?

vixen99 8y ago

Why is a submission with an accurately worded title linking to a paper from top-ranking institutions contributed by 18 authors flagged on HN?

usmanshaikh06 8y ago
"liberals"
flukus 8y ago
HN only likes science when it has PC conclusions.
- dang 8y ago
  Please don't post unsubstantive comments here. HN is divided on divisive issues. Anthropomorphizing it into something that "likes" what you dislike and "dislikes" what you like is just an illusion, but has become a rhetorical trick, as cheap as it is common. Please don't do that here.
Yetanfou 8y ago
For the same reason that Galilei and Copernicus came into conflict with the Roman Catholic church authorities, why Socrates was forced to drink poison for 'corrupting the youth': some ideas are not tolerated within certain societies no matter their scientific underpinning. In other words, those ideas go against the dogmata [1] of such societies. [1] https://en.wikipedia.org/wiki/Dogma https://en.wikipedia.org/wiki/Dogma
dang 8y ago
Because (a) you violated the site guidelines by editorializing the title (see https://news.ycombinator.com/item?id=17147115 https://news.ycombinator.com/item?id=17147115), and (b) to do that when the subject matter is divisive is flamebait, violating the guidelines in a second and worse way. HN's rules are the way they are for good reason. Please (re-)read and follow them from now on: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html. Threads are acutely sensitive to initial conditions. What you did made a very large increase in the probability that this discussion would be ruined before it began.