Sex, Gender, and Evolution

I love this quote from the XKCD blog:

The role of gender in society is the most complicated thing I've ever spent a lot of time learning about, and I've spent a lot of time learning about quantum mechanics.

Many scientists try very hard to de-emphasize this complexity, trying to reduce "human nature" down to parts and genes and behaviors that can be explained by evolutionary mechanisms, by hormones, by genetics. It's not nature vs. nurture and it's not just male and female, it's nature and nurture and infinite variations along a culturally and biologically mediated gender continuum. By trying to explain differences between male and female in terms of natural selection, we more often end up showing how our society has nurtured us to think about different gender roles than anything about evolution.

This is particularly true in the case of sexual selection, originally introduced by Darwin in The Descent of Man in 1871. In the book, Darwin writes about many animal species that have particularly noticeable differences between males and females and theorizes how competition for mates could lead to such differences. He also drops in the casual sexism of the time, unable to separate the rigid structures controlling men and women in Victorian England from his research on animal mating:

It accords in a striking manner with this view of the modificition and re-inforcement of many of our mental faculties by sexual selection, that, firstly, they notoriously undergo a considerable change at puberty, and secondly, that eunuchs remain throughout life inferior in these same qualities. Thus, man has ultimately become superior to woman. It is, indeed, fortunate that the law of the equal transmission of characters to both sexes prevails with mammals; otherwise, it is probably that man would have become as superior in mental endow man to woman, as the peacock is in ornamental plumage to the peahen.

-Descent of Man, page 565

The "scientific" question of whether or not women are actually stupider than men, while increasingly socially and politically unacceptable, is by no means closed. Articles are still being written about how women are "naturally" inferior to men intellectually, and how this relates to our ancestral conditions hunting and gathering. Even when not discussing human evolution and inborn intelligence, studies of animal sexuality continually are framed in terms of traditional gender roles (the coy, choosy female; the aggressive, studly male) while species or individuals that don't fit this narrative are ignored. Science news stories about duck rape become hugely popular because we apologize for rape as a "natural" event caused by the male evolutionary need to spread their seed widely. Biases and prejudices become natural, women's bodies are explained as in terms of men's desires, in our culture, in our media, and too often in our science.

More recently, the work of evolutionary biologists like Joan Roughgarden, who see the tremendous diversity in human and animal genders and sexualities not as something that has to be explained away to fit the dogma of the gender binary and sexual selection, but as the "natural" order of things (there's that word again), have started to gain acceptance in the academic and popular press. I recently read her most recent book, The Genial Gene (on recommendation from BoingBoing), and found it to be a fascinating alternate vision of the evolution of sex. Competition between the sexes is no longer at the center of natural selection, replaced by social forces in families and communities of animals. Her theory of social selection fills many of the gaps in theories of sexual selection, from the existence of homosexuality, transexuality and other intermediate genders and sexualities to the mathematical impossibility of females being able to calculate genetic superiority in nearly identical males and the lack of a correlation between secondary sex characteristics and fitness.

The book is a fascinating look at the technical aspects of evolutionary theory but in my opinion, her focus on "fact" and "truth" ends up hurting her extremely important and valid argument. Throughout the book she emphasizes that it does not matter whether we think a theory is morally or socially wrong, only what is true scientifically:

This book [does not] historically deconstruct Darwin or Spencer by situating them in their Victorian culture, nor does it provide a feminist-theoretic critique of the wealth and prestige attending those privileged to define the criteria for normalcy. And this book does not declaim social-Darwinist political theories or agendas. This book is different...One may find metaphors like "the selfish gene" and "the battle of the sexes" appealing or repugnant. Regardless of what we would like the truth to be, the issue before us is whether such metaphors correctly characterize biological nature.

As someone who loves feminist-theoritic critique I was a little disappointed that she didn't get into that argument, and as someone who also loves marxist-theoretic critique I was disappointed that her social selection theory was grounded to a significant extent in capitalist economic structures of game theory and "rational" decision making for maximum individual utility. Social factors, cooperation, and altruism are being increasingly seen as important drivers of evolution, even at a molecular level. It is easy for us to map molecular or animal behaviors onto human social structures as explanations, but the real "truth" is probably something very far from it and much more complicated.

There is still so much we don't know about how evolution has shaped our genes, our cells, our bodies, and our societies. It is hugely important that we recognize where our social mores can seep into our scientific thinking and perpetuate cycles of repression of those who don't fit the "natural" norm or making it difficult for women to speak their mind about social and scientific issues that affect us all for fear of being labelled ignorant of reality, intellectually weak, or--god-forbid--"cute."


More like this

Another great and, sadly, necessary post.
Stephen Jay Gould also wrote a great essay on these issues that 'evolutionary psychology' tries to address (such as 'explanations' of gender roles), a copy of which you can find here.

The quote that sums it all up for me is:
"We can only speak of of capacities, not of requirements or even determining properties ... if both darkness and light lie within our capacities, then we gain nothing by speculating that either (or probably both) lie within our evolutionary, adaptive, Darwinian heritage."

For every raper, there are hundreds of loving fathers in this world. That's not quite as newsworthy though..

studies of animal sexuality continually are framed in terms of traditional gender roles (the coy, choosy female; the aggressive, studly male) while species or individuals that don't fit this narrative are ignored

Manifestly untrue.
People who read Roughgarden's iconoclastic polemics should be forced to read this one, too.

As someone who loves feminist-theoritic critique..., and as someone who also loves marxist-theoretic critique

What a surprise. Have fun misapplying your favorite critiques to matters of non-human biology.

By Sven DiMilo (not verified) on 31 May 2010 #permalink

If you haven't read Roughgarden's "Evolution's Rainbow" yet, you should. The first 2/3 of the book is dedicated to examples of animals that go against the monogamous gender binary assumption (and there's quite a few), and the last 1/3 of the book, while it meanders a bit, focuses on the political ramifications of this assumption in our modern culture, particularly concerning intersexed individuals, as Roughgarden is an MtF herself. It is a really fascinating book.

her focus on "fact" and "truth" ends up hurting her extremely important and valid argument


Isn't that what one naturally does when trying to get one's arguments taken seriously by science types, rather than by consumers of woo?

It's because I don't think her theories are true yet, and I think she falls into many of the same traps as other evolutionary explanations that make analogies to human social structures. I don't think that only truth matters in this case, especially because science can never really prove that something is absolutely true, only disprove many many alternative hypotheses and have lots of evidence to support theories. Evolution is absolutely most likely true and many theories within evolution have lots of wonderful evidence, but the details of how evolution happens when we're talking about human social behaviors or sexuality is still in large part a social issue and in social issues it often doesn't matter who is right or wrong but which is best for the most people.

It is important to to distinguish a) attempts to figure out what happened in the evolutionary past, from b) drawing metaphors for ethical or political purpose. For the first, what "is best for the most people" doesn't matter one whit. And pretending it should matter seems to me the first step into woo.

I agree that social issues utilized to fill the gaps of scientific evidence could be detrimental.
As a researcher on gender dimorphism, I don't see how - biologically speaking - females could be considered 'weak'. It is a fact that women live longer than men. Physiologically, they have a liver more resistant to inflammation and cancer. Endocrinologically, they benefits from protective actions of estrogens on cardiovascular and skeletal systems. Genomically, having two X chromosomes, they are more protected to X-linked diseases.

It would save lot of back-and-forth if you would explain in a future post whether the "feminist-theoretic critique" you love is a kind of Harding-esque privileged epistemology (if so, some evidence of predictive power or of any contribution to the advancement of science would be helpful) or more like the "third way" Science Studies approach of someone like Kitcher, that recognizes the reciprocal influences of science and culture.

I love this post (and will read your latest one when I'm less tired!) and it seems unfair that people are picking on it a little. Just because Roughgarden wrote a book which explains how the social 'norms' of dominant males and weaker coy females is untrue doesn't stop every media outlet in existence from using it.

Any kind of scientific study on animal behaviour, especially sexual behaviour, gets forcing into social norms when explained by the media, presumably to make it more approachable.

Interesting story along the same lines; when the Burgess shale was being uncovered they found what they first thought was sexual dimorphism of an invertebrate, one form with a large protrusion, one with little tentacles. Based on no other evidence than a few squashed rocks, the researcher decided that the form with a large protrusion was the male, which used said protrusion to grab at females while mating. The one with little tentacles he decided was female. He never addressed what the little tentacles were for, presumably for waving around in a helpless feminine manner...

Yes, thanks dcotler! You make a very good point--my interest is always in how science and culture influence each other in ways that can be both positive and negative. I need to read a lot more and I need to be a little clearer on where I stand in future posts, I hope you stick with me through it :)

you are awesome! i just came across your article tonight when I was searching ecology and gender and then evolution of gender. I'm very glad I did!!