December 14, 2009

Joan Roughgarden on social evolution

Second part in a series about sex, gender and nature. In this post I look at the social selection theory of Joan Roughgarden.

Joan Roughgarden is a professor in evolutionary biology over at Stanford. I found her via a review of her new book The Genial Gene in the New Scientist.

The Genial Gene is one of the most radical attacks on Darwin I have seen in a long time. Not that she is a creationist arguing against natural selection, mind you. She does not, but she finds that the biologist's obsession with sexual selection to be questionable, and she and her research team puts up a fascinating alternative, called social selection.

Sexual selection

Sexual selection is based on the idea that individuals battle for their gene's survival in a fierce completion to get laid and get as many descendants as possible.

If you watch nature programs on Discovery or National Geographic you hear the same story over and over again: The tail of the peacock is large and colorful so that the male can attract females and have sex with them.

This narrative also confirms the stereotypes of human gender roles. According to Darwin males are passionate and females are coy. Still, the females have one important sphere of power: They select which male to have sex with, which is why males compete so hard between them. The fast and furious gets the girl.

This is relevant for transpeople, because these theories strengthen the social stereotypes of what it is to male or female. Any deviation from these stereotypes are therefore easily defined as something unnatural (in the true meaning of the word) and therefore something negative.

Sex and roles

Roughgarden does not deny that there males and females have different roles in the animal kingdom. But she does two things that are important for our understanding of the natural basis for sex differences:
  1. She reinterprets the behavior of males and females according to a new overarching understanding of evolution. By doing that she kills some of the stereotypes.
  2. She adds variety to the behavior of both males and females. There is no ideal macho male or sexy chick out there. In some species there are even different types of males and females, types that look and behave differently from others of the same sex.
Choosing a mate

The social selection theory of Roughgarden and her friends downplay the role of aggression and completion and focus instead on collaboration. She argues convincingly that there is no way the peacock hen can determine which male has the best genes based on the look of his tail. Indeed, research shows that the female disregard male plumage (Roughgarden 2009, p. 37).

Instead Roughgarden believes the female chooses to mate with the one she reckons will be the best to help her raise her offspring. Actually how the hen determines the parental capabilities of the male is a bit unclear to me, but in this respect her theory is at least as plausible as the old one.

Moreover, her theory (as opposed to the sexual selection theory) does not rest on the female's capability of finding the best man. You see, there is no hierarchy of genetic quality:

"All males are equivalent in genetic quality, except a rare fraction that obviously contain deleterious mutations and are present in a mutation-selection balance" (2009, p. 240).

I can remember how I as a young man reading about evolution, found it so hard to make sexual selection fit with what I saw around me. Clearly, it was not just the Queen of the Prom or the sexy soccer player that got kids? Most of my class mates got offspring, regardless of their looks or the brand of their car.

And if only the "fittest" of animals get offspring, why don't they all look the same? Why is there so much variation between individuals?

Reading Roughgarden makes it all make more sense, even if I think she downplays the role of aggression and violence a bit too much.

Compassionate Darwinism

Roughgarden says:

"According to social selection, what each sex does is subject to negotiation in local circumstances and statistical regularities in sex roles reflect commonness of circumstance.... Natural selection arises from differences in the number of offspring successfully reared, and particular behaviors are viewed as contributing to producing offspring and to building and maintaining a social infrastructure within which offspring are reared (Roughgarden 2009, p. 239)."

It is not the one who gets laid most often that win the race, but the one that manages to help his or her offspring survive through childhood. The best way of ensuring that is through collaboration and the division of labor, and that requires other skills than aggression and deceit.


Roughgarden again and again points to the enormous amount of variety found in nature. Collaboration can take many forms, and the behavior also changes over time. This is why closely related species like the chimpanzee, the bonobo and homo sapiens behave so differently.

There are, however, logical -- yes, even mathematical -- models that explain why such models of collaboration helps the survival of the species. I am not going into the details here, but if you have a mathematically inclined mind, take a look at The Genial Gene. In that book she demonstrates through game theory that collaboration is more effective than cheating for the survival of your own genetic lineage.

Sex and collaboration

According to the sexual selection narrative, male and females are in conflict and cooperation is at best a secondary development.

In Roughgarden's world things are different:

"According to social selection, male and female mates begin with a cooperative relationship because they have committed themselves to a common 'bank account' of evolutionary success. Their offspring represent indivisible earnings from a common investment. As such, conflict develops only secondarily if a division of labor cannot be successfully negotiated."

Roughgarden takes this propensity towards collaboration so far that she argues that males are not promiscuous by default. Male promiscuity is a strategy of last resort that occurs when males are excluded from control of offspring rearing. (I am not so sure about this one, especially when it comes to the males of homo sapiens, but I am willing to go give her -- and men -- the benefit of doubt.)

Sexual selection theory on the other hand describes monogamy as an entrapment of males by females. Males do not want all the hassle of rearing kids, but they accept it anyway in order to get laid.

Roughgarden takes the logic of collaboration down to the level of sperm and eggs.

In biology the difference between male and female is determined on the basis of the size of the gametes (sex cells). Following the logic of sexual selection the sperm seem to be cheating on the egg by forcing "her" to do all the hard work. In social selection the difference in sizes is a practical way of ensuring a successful conception. The big egg is easier to find for the sperm. Moreover, it contains the provisions needed for the first period of growth.

Power cliques

So what about the peacock's tail?

Well, Roughgarden does not think male ornaments (feathers, antlers etc.) are there for the female to judge the genetic quality of the male. She believes male and female ornaments serve as "admission tickets" to "power-holding cliques" that control the opportunity for successful rearing of offspring.

Again, this makes sense to me. A man doesn't buy an expensive car just to impress the girls. He buys it to impress his mates. He signals that he is successful and that he is one to be invited to the parties of the in-crowd.

Again and again I have been told that women dress up etc. to attract males, but the fact is that most men (apart from cross-dressers, that is :-) are unable to distinguish one brand of make-up, clothing or perfume from another. They will find a decently dressed woman attractive without knowing the secret language of women. The reason women put so much effort into shopping and brands, is first of all that they want to fit in with their fellow sisters, i.e. "the power cliques" of Roughgarden.

All right, but if this is the case, why doesn't the peacock hen have colorful plumage? The hens should, like human women, also strive to join cliques, right?

This is where Roughgarden gets a little vague. She has no general explanation of why male animals, as Darwin argued, seems to have more ornaments in general. In the case of the peacock, however, the explanation is simple: The female protects the eggs, so she has developed camouflage colors. I guess all the blue hens were killed off before their eggs hatched.

Another obvious argument would be that our tendency of interpreting blue feathers as more sexy than brown feathers, or big antlers as more impressive than no antlers, is biased. The male peacock clearly find the brown hen amazingly attractive.

Why is woman more ornamental?

As you probably have understood by now, I find this immensely fascinating, and again I am reminded of discussions I had when I was younger.

I guess it was the autogynephiliac in me that had to ask the obvious question: If the male is the one with the colorful feathers, why is it that it is the human males who are grey and bland and the human females who are beautiful, colorful and have the more prominent curvy "ornaments"?

I admit I am a bit gynephiliacly biased here, but my impression is strengthened by the fact that in most cultures women also wear more ornamental and colorful clothes.
Believe it or not, but evolutionary biologists have taken the lack of male plumage seriously. Some of them argue that the human male ornament (the one used to impress the girls) is not their body but their brain. Men have developed huge brains to outsmart other men and thereby win their way into a girls heart. (No, I am not making this up!)

This immediately leads to the question: Why have females developed equally smart brains? Well, to appreciate the genetic quality of the male brain, of course!

Evolutionary psychologist Geoffrey Miller puts it this way:

"If hominid females happened to develop a sexual preference for creative intelligence, then males with more creative intelligence would attract more sexual partners and would produce more offspring. Those offspring would inherit both the taste for clever courtship and the capacity for producing it. Over many generations, average creative intelligence in the lineage would increase rapidly, perhaps explaining why brain size tripled in just two million years."

Note that Miller doesn't make the obvious conclusion: that the females' have gotten bigger brains in order to attract males. Males are clearly not able to appreciate female intelligence! We go for tits and asses, and not for the woman's ability to help us raise our kids. So much for the big brain!

Seriously, I don't know where to begin...

Why am I telling you all this? Because we have to read all of this "authoritative" science for what it is: stories told by men and women like you an me: people who have their own hang-ups and prejudices.

Sexual differences

Let's get back on track:

Sexual selection theory find it hard to explain why some species have no or only small visible differences between the sexes (cp. penguins, sparrows or wolves). They normally explain this by saying that this happens when females lack a sense of aesthetics (!). This very argument does, of course, weaken the whole sexual selection theory.

For Roughgarden "sexual monomorphism" signals the absence of same-sex power cliques: "This should occur in ecological situations where the economically efficient coalition is the coalition of the whole," she says (p. 243).

Sex-role reversal

In some species we see sex-role reversal: The male provide more parental investment than the female.

This should not happen according to the sexual selection narrative. This narrative says that males should do less parenting, because the sperm is smaller than the egg (long story!). According to Roughgarden, this kind of natural feminism makes perfect sense. It is just another type of useful contract based on negotiations in that particular ecological niche.

Transgender animals

It is when Joan Roughgarden goes on to describe "gender multiplicity" it gets really interesting for a transgendered person. That's the topic of my next post.

Postscript on Joan Roughgarden

As I noted earlier, most scientist do not rock the boat. They do not challenge the ruling paradigm for a lot of reasons, the main one being probably that it was the dominant mentality or belief system of a discipline that attracted them to it in the first place.

That leads to the question of why Roughgarden has made such a radical stance.

I didn't read her own history until after having read The Genial Gene. Then it all became clear. Roughgarden is an M2F transsexual.

So far I haven't seen any serious attempts at debunking her theory on the basis of her personal history. It seems her position in the academic world is too strong for that to happen.

[Photo of Roughgarden: Nature]

She did not have to leave Stanford after her transition, partly because of strong support from Condoleezza Rice, the university provost. Yes, we are talking about the Condy Rice! Some times real life is much stranger than fiction.

Anyway, we must be as critical towards her science as we are towards the traditionalists. She openly admit that she has an agenda: to develop a theory with room for outsiders like gays and transsexuals. That might lead her to ignore findings that go against her theory of collaboration.

See also:
Roughgarden on transgender animals


Roughgarden, Joan: The Genial Gene, Berkely 2009. Click here for Google Books excerpt.
Nudging Darwin over the rainbow SFGate on Roughgarden

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