Saturday, May 07, 2005

The Roughgarden Lectures

As I mentioned in a previous post, recently Professor Joan Roughgarden of Stanford came to OSU to talk about her new book Evolution's Rainbow and her views on how Darwin's "sexual selection" might need to be reformed.

Her second lecture included much of the content from the first lecture plus a few more technical details, so the two lectures basically can be blurred together in the one big summary here. Now, keep in mind that the first lecture was given to both science students and humanities students because the first was a joint lecture between the two schools. Thus, the beginning of this summary will seem a little "dumbed down" with respect to some of the biology.

At the beginning of the first lecture, Roughgarden was introduced by the Dean of the Biology school and then played a 20 minute BBC program on herself and her work. She wanted to do this so that we could decide if she was "biased" in some of her research because of her own personal history. You see, she's asking scientists to discard some of the fundamentals of evolutionary biology and reexamine all of their previous data. Some say this revolution is justified, but others say that her new research is completely driven by her own biases, and this behavior doesn't belong in science.

The details of all of this bias talk was outlined in that video, and is also discussed in the a Stanford alumni association article about Roughgarden that Spice mentioned as part of a comment on my previous post.

You see, Joan Roughgarden used to be a man. As a man, she served on the faculty of Stanford university during the time that Condoleeza Rice was provost. Before she made the transition, she went to Rice with a letter outlining all of the contributions that she had made up to that point and an explanation of her decision to become a transgender woman and asked that Rice let her stay on the faculty. She said that during the meeting she could watch Rice read over each sentence of each paragraph, very deliberately, until the end. Rice looked up from the letter and said that she would let her stay. At that point, Roughgarden showed Rice a picture of what she'd look like after the change. Rice said that she'd be a very beautiful woman and suggested some places to buy clothing. Roughgarden said that Rice's choices were a bit conservative for her taste, but she appreciated the gesture.

[ As a side note, Rice has described herself (while being a part of the Bush administration) as being "mildy pro-choice." I wonder if there's a bit of a liberal wrapped up in there somewhere that has been stifled by conservative force surrounding her... I'm not saying I like her. I'm not saying I think she's qualified. I'm not really making any judgement at all. I'm just wondering about her politics... That's all. ]

[ Another side note: Roughgarden mentions that it's impossible to talk about these topics without also talking about humans because questions about the impact on human behavior always come up. This is her justification for why she's started to move into the area of anthropology (she's been criticized for this because she is not an expert in anthropology but she invokes anthropological examples as if she was). ]

Now, why is any of that relevant? Well, you see, Darwin (and Alfred Russell Wallace, a friend of Darwin's who did this independently and co-authored the first paper on these with Darwin) really came up with three big theories:
  1. Evolution from common descent
    • The reason why all living things share so many commonalities is because every living thing evolved from the same one (or very few) things. I can look at a dog's "face" and point out his eyes, nose, and mouth and know what they all do because I'm familiar with the same structures on my own face and I know what I use them for. I share those with the dog because we're evolutionary cousins.
  2. Natural selection
    • Explains the variation in nature -- speciation itself. Just as breeders can "select" for a particular trait, the environment (both biotic and abiotic) can select for particular traits. A breeder can breed for chickens that have high egg yields by preventing those with low yields from doing further breeding. Nature, through survival pressure, can do the same thing. Because nature is diverse (again, keeping in mind both biotic and abiotic pressures), the selection will also be diverse. My eyes see color but require lots of light to do so. A dog's eyes see black and white but do not require as much light so can see in the dark better than mine. It's about tradeoffs. Nature trades off things that aren't as important for those things that are important. Eventually we get speciation.

      [ Intelligent designers have the major problem with this theory. They say that components are too complex to be selected for this way. They say that it's just not probable, so it's more probable that there's a designer that built these complex mechanisms instead. However, scientists can show that "irreducibly complex" mechanisms actually are reducible into simple components that can serve some function even without their sister constituents... ]
  3. Sexual Selection
    • There are certain aspects of species that simply cannot be explained through natural selection. Why would a male peacock have such elaborate feathers that clearly provide no survival ADVANTAGE? Darwin's explanation was that females are selecting these males for their "good genes" and those good genes would be reflected in the elaborate displays. Later work (Zahavi, etc.) elaborates on this with the idea that survival IN SPITE OF having such costly characteristics shows females that this must be a good male.
The first two have been wildly successful. Scientists believe that they are as close to what you could call "scientific fact" as anything could be. The third is the least understood and has had the least contribution. It is that third theory that is the focus of Roughgarden's lecture.

You see, Darwin said that universally all females would be coy and all males would be "passionate" and showy. Darwin believed that females had the greatest investment in the care of offspring, so females would be "choosy." These sentiments have been echoed through research up through today.

Roughgarden thinks this whole theory is wrong and that Darwin was being influenced by his own bias. That is, Darwin said that variation in characteristics made a species robust. Variation was a good thing. Variation brought with it speciation. We should cherish variation... EXCEPT when there's variation in sexuality. Sex roles were set in stone. Sex roles were universal. If there was a deviation from the standard sex roles, then that deviation would be costly. Her point here is that we have thrown out the idea of one "perfect bird" and all others being lower forms of that bird (the basis of taxonomy was based on this idea of a "perfect" specimen); however, we have the same archaic philosophy about sex and sex roles. There is a "perfect" sex trait and everything is is a degenerate form of it.

So Roughgarden is pushing for something she's calling "social selection." She wants to come up with new social models that take into account sex and show that sex may have more to do with the social nature of animals and less to do with reproduction ALONE. She's not saying that homosexuality is a way for men to "practice" sex (in fact, she says that insults the animals). She's saying that homosexuality (and sex in the off season) serves other purposes that help keep a society glued together.

She gives a few examples of how Darwin's sexual selection just doesn't hold in all of nature. Before I give them, I want to stress that the biologist's definition of "male" and "female" purely has to do with the size of gamete (sex cell) produced. If you produce a small gamete (e.g. sperm), then you are male. If you produce a large gamete (e.g. egg), then you are a female. The few examples that I remember:
  • Sea Horses
    • Sex horses (and the related piper fish?) have an interested "sex role reversal." Sex horse males have a skin flap that they use to collect female eggs (picture a stomach pouch -- a sea horse fanny pack). Once collected, the sea horses can fertilize these eggs and nurture them until they're ready to hatch. The males then "give birth" to these sea horse offspring. Because of this shift in "investment," then sea horse females tend to be the aggressive type and sea horse males tend to be more coy and choosy.
  • Certain Fish
    • There are certain types of fish that have three male "genders." All three produce sperm; however, they behave and look very differently. In these cases, the large male is territorial. He secures a territory and waits for a female to swim by. The female swims overhead, picks her territory, lays eggs in that territory, and swims off. The male then fertilizes those eggs. The second type of male, who is noticably smaller, hides near that territory and waits for the female to lay eggs. Wehn she does, he darts outs and fertilizes as many as he can before he is chased off by the larger male. This actually puts a check on the size of the large male territories; if the territories are too large, he will spend all of his time chasing off perimeter males. Now, the third type of male is not only smaller but has female features. On top of that, the large male will actually COURT this third type of male using similar behaviors as are done to court females into his territory. Once the third type of male has been courted, he accompanies the large male back to the territory. These territories that have two males in them tend to be favored by females. When the female lays eggs, both males fertilize the eggs and chase off foreign perimeter males.
  • Similar stories in birds
    • There are nearly identical stories with birds as the fish story above.
  • Gender in Marine Wildlife
    • There are lots of examples of marine animals changing genders throughout their lifetimes. Take Nemo, for example, who is a clownfish who will change gender late in life. There are lots of other animals that determine gender by temperature at a particular time in life. Gender is much more fluid in these cases, and with it behavior is also more fluid.
  • Homosexuality in Animals
    • There are over 300 known examples of homosexuality in animals (and this doesn't even count sex outside of the mating season, which is equally "odd"). Homosexuality simply isn't uncommon.
So she wants to start looking at reproductive social behavior as a part of a cooperative mechanism among groups of animals. This is what she means by "social selection" replacing "sexual selection." At this point in the first lecture she told us that it would be the focus of the second lecture, so she continued discussing homosexuality in particular and how science and religion have a backward view of homosexuality. I'll mention the homosexuality arguments briefly here and then move onto the day two lecture stuff.

She started pointing out that now that people are seeing that homosexual behavior may be something that is natural, then people are looking at it as some form of "genetic disease" that doctors might be able to find in the future and "fix" ahead of time. Now, whenever someone says "genetic disease" you should start thinking about population dynamics. If something is a genetic disease, there should be consequences on how frequently it is expressed in the population. For example, let's say a certain "genetic disease" is fatal. That is, let's say that anyone with that disease will not survive long enough to reproduce. This trait should only be seen in something like 1/10000000th of the population, because that is roughly the mutation rate. As the disease becomes less "fatal," it should be seen more often.

So if we use number of offspring as a proximate for fitness, there is a 100% reduction in fitness for a fatal genetic disease, and thus genetic traits that express themselves in only 1/10000000th of the population correspond to a 100% reproduction in fitness if they are a disease. You can keep doing this up the ladder. You can ask, "How frequently is that trait in the pouplation?", then take the answer and find out what the corresponding reduction in fitness is.

Depending on how you define homosexualiity, there are somewhere between 2/100 and 10/100 of the population who are homosexual. That corresponds to a 0.1% decrease in reproductive fitness. Take any room of people (for example, the room that the lecture was given in) and you have more than that amount of fitness differential among them. In other words, 0.1% gets lost in the noise. It makes no difference.

So this shows that homosexuality cannot be a genetic disease. It survives, and it probably had some function. (unfortunately, M.D.'s don't study population dynamics, so they wouldn't understand this)

She then goes on to talk about different societies and how they view homosexuals and transgenders (specifically transgenders). She pays particular attention to the references to eunuchs in the Bible and how the Bible (that otherwise says NOTHING about sexuality) actually embraces eunuchs as a normal part of life. In fact, modern day Biblical scholars consider eunuchs to include homosexuals. This implies that there were plenty of homosexuals during Biblical times.

So after all of this, Roughgarden says that science says homosexuality (and related) is unnatural, and she believes this is wrong. She also says that modern day religion says that it is SINFUL, but Biblical references do not back that claim up, so religion is also wrong. These two forces are doing great damage and both need to be fixed.

Now onto the second lecture. As I said, it started much like the first. However, she demonstrated the use of cooperative game theory to model some of these social interactions.

Now, cooperative game theory isn't publically understood much. You see, most economists use competitive game theory because acts of cooperation are usually made illegal by government. Most of biologists' use of game theory has been influenced by economics. However, theoretical biologists like Roughgarden have just recently (in the last two years) learned about "coooperative game theory" (guess who they learned it from) and have started to apply it to try to understand social behaviors in animals.

Let's say you have a two player two strategy (i.e., a 2-player bimatrix) game. It may have a pure strict Nash equilibrium at ([0,1]', [1,0]'). However, due to bargaining on the side, there may be a mixed equilibrium at ([0.25,0.75]', [0.75,0.25]'). In other words, compromises can be made where one party gets what they want SOME of the time just as long as they give the other party what they want SOME of the time. Cooperative dynamics change things.

Now, there are ODEs that model these dynamics, and the models that Roughgarden and her collaborators (guess who they are) have used have successfully described the behavior of the three-male fish mentioned above as well as a number of other examples. She believes that these cooperative models can go beyond needing "sexual selection" to describe strange behaviors and traits. These cooperative models can show sexuality to be just another social lever that groups of animals use together. This could help explain why wolves, for example, sleep in packs together. This could help explain why bonobos have SO MUCH SEX (for example, females will go from female to female engaging in 15-minute missionary-style vulva-vulva sex that brings them both to orgasm and then separation as they look for their next partner -- these are some of the many reasons why they don't let you see groups of bonobos in a lot of zoos).

And so this leads us to her collaborators. I sat next to my adviser. He recognized her main collaborator's name immediately. She is an Aero. Engineer at Stanford doing work in Controls Engineering with UAV's.

[ I'd like to highlight CONTROLS there. You see, John Maynard Smith ORIGINALLY was a CONTROLS engineer, even though everyone calls him an Aero. Engineer. When you say "Aero Engineer" you picture PDE's describing fluid dynamics. However, these engineers are more interested in the ODE's describing system dynamics. Yes, these engineers may have spent a lot of their work in the aero realm, but they do controls work. I'm an Electrical Engineer, so I probably know a little bit more about E&M, OpAmps, and the quantum mechanics behind silicon IC's, but I'm a CONTROLS engineer. Most of my experiments may be electrical, but many of them are not, and at the conferences I go to there are just as many AE's as there are ECE's, and we're all interested in each other's work. ]

You see, my adviser and I do work in controls engineering with UAV's. We specifically work with robotic behavior modeled after solitary and social foragers. We use game theory to find optimum strategies among groups of UAV's and robots and even very general engineering manufacturers participating in a market environment together.

So it was fun hearing Roughgarden talk about not being very familiar with COOPERATIVE game theory. It was sorta fun when my adviser asked her a question about "playing the field" (a term originating with Maynard Smith's work) and her not really understanding the very common expression. Engineers have been using game theory for a long time -- many of the things we build play a "game" with the environment around them, and so game theory has been very helpful in engineering applications. However, engineering applications aren't bound by laws like the economic applications are, so we've done a lot of work with both competitive and cooperative game theory.

So just as Professor Waite has worked with us to try to explain dynamic behavior in animals, apparently Stanford controls engineers are working with Roughgarden to do some of the same things!

So it was neat to know that what we're doing (which is very novel and strange and a new direction in engineering) is also going on at Stanford, and we engineers have a lot to contribute. (note that we also get a lot out of the exposure to the existing work in bio -- it's a two-way street)

So that's basically what I got out of it. Neither presentation had a lot of meat. I saw a payoff matrix and a slide of four ODE's. Otherwise it was all animal examples.

My reflection? I think she has a lot of good points. I do think she's biased, but I don't think that's necessarily so wrong. Yes, her critics say that it's the scientist who is supposed to keep from being biased. It is science specifically that resists all bias. However, that's not practical, and if she's right then there's a lot of merit to what she's doing. On top of that, as she points out, there's not a whole lot of productivity that you can get out of sexual selection research. However, the ground is really fertile for further work to be done with her approach. Her approach gives a lot of direction and promise. It's worth a shot.

Now, during this lecture, I realized that the evolutionary geneticist that I mentioned a LONG time ago in a post about my last day in EEOB740 (the lecture with the snotty anthropologists in it) was sitting two rows in front of me. Apparently she saw me walk in and smiled and all that jazz, but I didn't notice until she turned her head back toward the front of the room. I should have said something to her after the lecture, especially because her (kinda cute) friend left in the middle of the lecture so she'd probably be walking off alone anyway. However, I still don't know her name, and I figured she'd be hanging around to talk to Roughgarden anyway...

So that's that. :) It was fun. Yay. And this was a long post.

1 comment:

Anonymous said...

For an English class, we were asked to read an article of our choosing and write a paper about our opinion of the article; mine was Joan and her theory. I like what you said about her possible bias, if it weren't for her experiences, she wouldn't have had the interest to do the research in the first place. Her ideas I believe are extremely credible. She has quite a bit of evidence to back up her theory of social selection. Darwin's theory came out in 1871. How much research did he do? We have evolved tremendously has humans in the last 150 years and it's time we bring this into the 21st century as well.