Men are stronger than women (on average)

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Citation: Leyk, D., et al. “Hand-grip strength of young men, women and highly trained female athletes.” European journal of applied physiology 99.4 (2007): 415-421.

51bCI-7YlbL._SY344_BO1,204,203,200_Every now and then there is a debate on who is more “anti-science”, the Left or the Right. I’m not too interested in the details of that, but, a few years ago I expressed my skepticism to Chris Mooney, author of The Republican War on Science, that liberals were somehow reflexively more “pro-science.” I suggested to him, for example, that when it comes to aspects of the biological basis of human behavior, with the exception of homosexual orientation, liberals are highly resistant to accepting any differences across groups because of their adherence to social constructionism. Chris brushed this off, suggesting that the “science wars” were over, and even when it came to evolutionary psychology (broadly construed) the liberal Left had conceded to the best evidence on hand. I was not moved, because I’ve had years of exchange with many liberal Left folk who defy Chris’ assurance to me. This is most notable when it comes to sex differences, which are usually seen as less controversial, and evolutionarily should have some prior expectation due to dimorphism.

To give a concrete example of how far this goes, there are many liberal Left people who won’t even accede to the proposition that men are, on average, stronger in terms of upper body strength than women. A few years ago this came up on social media, where a friend who has a biology background from an elite university, even expressed skepticism at this, when I was trying to get her to be open to behavioral differences between the sexes by starting with something I thought she would at least agree with as reasonable. When I saw the lack of unequivocal acceptance of this point I decided to opt out of the conversation. This was basically face to face with Left Creationism.as-nature-made-him-john-colapinto-21239181

This is not to say that people are totally in denial. Rather, the standard educated tack by those with progressive tendencies kicks in. There are “problematic” terms which need to be “contextualized,” and “difference” needs to be considered as an expression of socially preferred categories and measurement. After the critical theory verbiage is hurled usually sane people want to run out of the room.

But on Twitter recently I saw an article which quantifies the difference in concrete ways. To be honest the difference shocked me. The paper is Hand-grip strength of young men, women and highly trained female athletes. As you can see in the figure above the sample sizes are large. The N = 60 of top female athletes consisted of those who competed in judo and handball, to select for individuals who were already geared toward upper body activities. The very weakest male in the data set of nearly 1,700 males looks to be about at the 20th percentile for average women.

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The upshot is that the very strongest female athletes are barely above the median of grip strength for men. The top 75th percentile of female athletes are below the bottom 25th percentile of men. Another way to look at it is cumulative distributions. You can tell looking at this that there is overlap between the two sample distributions. How much? Ten percent of women have stronger grips than the bottom five percent of men. The difference in distributions is big enough that the very strongest non-elite athlete female in the whole data set has a weaker grip than most of the men.

fig4At this point the intelligent obscurantist will probably make an appeal to something about a confound. But the researchers had a data set of men and women in their early 20s, of a wide range of body types. To the right you see a plot of average grip strength as a function of lean body mass. The further to the right, the more muscular the individuals are. As you can see the more muscular men and women are, the stronger they are. But you can also observe that even the most muscular women can barely beat the least muscular men.

To a great extent I feel like an idiot even writing this post. Who doesn’t know the extent of this biological difference? Well, lots of people at a minimum pretend not to. I’ve interacted with people about genetics for 13 years now. I’m someone who leans to the Right, but I want to think the best of everyone, and really empirical data is my summum bonum. It doesn’t make me happy to know that the flight from reality has gone so far in some sectors. I am aware that most reasonable people on the Left half of the political distribution would have no problem assenting to the facts here. The problem is that a vocal minority who will “problematize” what should be rock solid facts are not marginalized. This group is so loud and fixated on these topics that they begin to shape perceptions. After all, it isn’t every day that a man is going to challenge a woman to an arm wrestling match. And if you watch superhero movies you know that there are plenty of “butt kicking babes” who more than hold their own. But here’s the thing: superheroes don’t exist, movies are made up!

Perhaps these ideas are stronger than I think, because I’ll be honest that I was a bit surprised by the magnitude of the difference. It is fashionable, and defensible, to talk about averages, but these results point to the possibility that on some biophysical metrics men and women exhibit disjoint distributions. In other words, it is reasonable to treat them as distinct and separate categories in near totality.

Mind you, in a population of millions there will be many strong women who can beat many men. But the results from top level athletes should make us aware just how rare these individuals will be. As individuals they are somewhat sui generis. On the whole I am willing to grant the value of individualism on the legal level. Men and women should be allowed to become fire fighters with sex or gender no bar, and honestly I feel the same for volunteer combat troops. There are women who are physically and mentally in the population capable of competing with and besting most men at tasks which they would have traditionally been barred from on account for their sex. But for some traits they are very rare, because sex matters a lot in development. That is a biological fact.

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