Jump to content

Joan Roughgarden's Social Selection Theory

Recommended Posts

So, what do you think of Joan Roughgarden's approach to the evolution of sex? She's "thrown down the gauntlet" as Seed magazine's Maggie Whittlin writes, challenging that the neo-Darwinist view of sexual selection as being largely competitive is wrong.


Has anyone read her book, Evolution's Rainbow? I read the first chapter while wasting time in Chapters but I don't feel I have a good grasp of that book. Is it worth reading in entirety?


I feel that she makes some really good points -- a lot of sexual behaviours are not well explained by Sexual Selection theory. Role-reversals or organisms that do not have differentially sized gametes are two examples that she used. But part of me is resistant because she has such a "the world is beautiful because it's diverse" mentality -- I feel like she's almost brought morality into this.






I suggest that we replace sexual-selection theory with a new approach that I call social selection theory. I argue that reproductive social behavior, including mate choice and family organization, can be completely explained by focusing solely on the direct ecological benefits each individual obtains from the interactions it has with others. Indirect genetic benefits can be ignored; they don't realistically factor into mating decisions at all.


Social selection theory proposes that every animal has a time budget for its social interactions. Each animal interacts with others in ways that improve the number of offspring he or she can successfully rear. Animals may pursue their most beneficial course by acting independently or by acting together in teams, but usually in teams. From a group's many instantaneous decisions as to whom to associate with and what actions to perform with one another, a unique social system emerges for each species in each ecological situation.


In social selection, cooperation is purchased when animals barter for control of reproductive opportunities. One morph of fish, say the large controller-gender of blue-gill sunfish, is programmed to breed after five years. The fish may die during this time, but if he survives, he will be big enough to control territory in which females lay eggs. This fish can offer fertilization of the eggs laid in his territory as a payment to smaller, shorter-lived cooperator morphs. Cooperators provide services such as helping to attract female visitors to a territory or keeping the territory clean, while the big controller rebuffs neighboring large males.


This kind of bartering and team play is the subject of cooperative game theory, a branch of mathematics with theorems tracing to John Nash (the Princeton economist made famous in the recent movie "A Beautiful Mind"). Cooperative game theory also predicts the emergence of cooperative coalitions. Family structures such as monogamy, polygyny, and polyandry can be considered the outcomes of a cooperative game. Players weigh the direct benefits they can obtain while making choices about whom to associate with. Achieving cooperative solutions requires coordinated actions and staying in close contact. Same-sex sexuality and intimacies such as grooming and tongue-touching evolved to help animals stay in touch with each other's condition and intentions. This knowledge helps them work together as a team.


In social selection, the expensive tail on a peacock does not seduce a peahen. Instead, that tail is primarily a badge that earns the peacock membership in male power-holding cliques. In social selection, secondary sex characteristics like the peacock's tail are more important for same-sex power dynamics than for between-sex romance. Such traits are used to secure admission to resource-controlling coalitions and must be expensive to ensure exclusivity. They are not signs of genetic quality advertised to females. Such traits may indeed connote physiological health and good condition, but this indicates a male's ability to offer direct benefits to a female rather than his genetic quality. She should choose a male displaying good condition not because he has high quality genes, but because she will be able to raise more, not "better," offspring by mating with him.


Instead of judging a male by his genes, females look for how much he can directly contribute to the survival and provisioning of young. For example, lion cubs are often killed when a new male takes over the pride. Their mothers may mate with the new ruler to give him a share of the paternity, and thereby reduce the likelihood that he will commit infanticide. Female peacock wrasses choose to lay eggs in the territory of a male whom they assess as likely to stay and guard the eggs rather than swim away for bigger egg masses somewhere else. Such immediate benefits of avoiding mortality to the young far outweigh any possible advantages from superior genes. Nor do females always consider male-male combat the best indicator of a superior mate. In sand gobies from Scandinavia, experiments show that females preferred males who protect eggs from predators, not males that jousted with other males and won. Animals are primarily concerned with the number of offspring successfully reared, not with the genetic characteristics of those offspring.


To a naturalist, the failure of sexual- selection to describe and explain animal behavior is reason enough to reject it at this time. But the stakes are even higher. Sexual selection is not innocent. It promotes a view of nature as violent and deceitful, emphasizing male-male combat and war between the sexes. It licenses male promiscuity. It views female choice of mates as a broom to clean the gene pool of males with bad genes. It persecutes diverse expressions of gender identity and sexuality. Social scientists and the popular media uncritically reproduce its myths.


To be clear, the scientific truth, or lack of it, of sexual selection is logically independent of its social implications. Yet, the ethical wrongs issuing from sexual selection's narrative require holding it to the highest standards of scientific rigor. It fails. After 130 years, sexual selection is still not confirmed and I suggest it never will be.


Once scientists start looking through the lens of social-selection, animal behaviors become much easier to understand, and many of the apparent contradictions fall away. Instead of trying to shore up Darwin's sinking theory of sexual selection, we should be improving our understanding of gender and sexuality, because friendship, love, and sex are important.

Link to comment
Share on other sites

I have read through Ms Roughgardens paper in Science 311(5763) p965 17/02/2006 because I wanted to see whether she really did not understand evolution. I am glad to say that that is not the case but, as all too often happens with evolutionary biology, she has decided to take a swipe at Darwin and get a bit of extra publicity.

In this case, Darwin's ideas about sexual selection were very primitive, the Law of Evolution was pretty new then - and there is a slightly Victorian attitude about it but the implication that the notions behind sexual selection haven't moved on since then is disingenuous. Her supporting references are from 1871, 1938, the times literary supplement and Elle magazine plus her own book and one contemporary source - if you want to say Charles Darwin is wrong you've got to do better than that.


Whats wrong with her 'new' theory is that it is implicit in sexual selection:

There are two points worthy of mention.

The first is in this quotation from the paper

"We think that the notion of females choosing the genetically best males is mistaken. Studies repeatedly show that females exert choice to increase number, not genetic quality, of offspring and not to express an arbitrary feminine aesthetic."


The authors have transmuted 'best male' into 'highest genetic quality male'. The best male is the one that will chaperone the largest number of copies of the females genes into future generations. Whether it is because he is the brawniest or the most likely to be a good father are equally relevant. The idea of 'choice' here is a metaphor. The authors were not trying to suggest that the parents were making an informed decision based on reasoning - i.e. and that there was no evolutionary basis to the selection. The choice represents the preprogrammed behaviour handed down by generations of users of that successful behaviour. Only the best choice will be made as the 'choosers' of any other behaviour will not have produced heirs (given a stable environment)

The last three words seem to be supported by a piece of purple prose abstracted from another book and they are out of place in a theory about evolutionary selection.


The second point is from the conclusion of the paper

"The key elements to social selection are: (i) Reproductive social behavior and sexual reproduction are cooperative. Sexual conflict derives from negotiation breakdown. In sexual selection, sexual conflict is primitive and cooperation derived, whereas in social selection sexual cooperation is primitive and conflict derived. Hence, sexual selection and social selection are mutually exclusive theories."


Conflict and cooperation are deemed to be mutually exclusive but that is only true in the case of a zero-sum game. The individuals, either male or female may or may not be in conflict but their objective never is achievable solely by beating the other. Whether objectives of the sexual partner of an individual (to get their genes into the next generation) is helped or harmed is irrelevant to the objective of getting your genes there, and it is those genes that carry the behaviour that got them there.

Some of the reasons for making the purely selfish choices that go to form a tremendous variety of sexual stratagems are nicely explained in the paper and the worst that can be said of sexual selection is that it can be, and very frequently is oversimplified into strong, promiscuous males and cautious, home-making females especially in the popular media.

Perhaps it is the continual drawing of this analogy with human nature that does not sit comfortably.

Link to comment
Share on other sites

  • 2 weeks later...
At the age of 51, Jonathan Roughgarden had himself transformed into Joan Roughgarden, and in 2004 published a popular book entitled Nature’s Rainbow (University of California Press). It was a work of self-justification, in which a personal agenda was overtly discussed. Had Roughgarden simply argued that there is more to reproductive strategies than just male combat and female choice, and presented some reinterpretations of the data, there would have been no reason to respond. But here we have an effort to discredit perfectly good science. To suggest, on the grounds that it may not explain everything, that sexual selection or any other scientific theory is wrong, is an offense against elementary logic and common sense. In claiming that sexual selection is false, Roughgarden has created her own mythology.



Ghiselin got a bit steamed on that one. That little bit at the end with the direct personal attack was a little bit painful.


After reading her article I was actually suprised that Science published it. Even I had no problem with debunking her theory's and I am no evolutionary biologist. It was overall a very week premise with a clear misunderstanding of evolutionary theory.


I imagine this will be hotly discussed for sometime and then quickly fade away.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.