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- The music of H1N1
- Justice Souter retiring?
- Hobbits.
- DOJ investigating Google Books settlement.
Female orgasm eludes evolutionary explanation. Most candidate explanations have a hard time reconciling the observation that a large fraction of women do not have orgasm during intercourse and among those that do it is not a consistent occurrence. Here is a fun paper surveying a variety of just-so stories that “explain” female orgasm. The authors dispense with
- Its a non-adaptive vestige of male orgasm.
- It encourages females to have more sex. (then why not always?)
- It encourages females to have sex with multiple partners (thus the asymmetry in “arrival times” between males and females.)
- It improves chances of fertilization. (empirically false)
and they leave us with an intriguing, relatively new one, the Evaluation Hypothesis.
When Barash was a graduate student more than ten years earlier, he observed that when subordinate male grizzly bears copulate, their heads are constantly swiveling about on the lookout for a dominant male, who, should he encounter a couple in flagrante, will likely dislodge his lesser rival and take its place. Not surprisingly, subordinate males ejaculate very quickly, whereas dominants take their time. If female grizzly bears were to experience orgasm, with which partner would you expect it to be more likely? And is it surprising that premature ejaculation is a common problem of young, inexperienced men lacking in status and self-confidence? Moreover, is it surprising that women paired with such men are unlikely to be orgasmic?
So it doesn’t encourage more sex uniformly, it encourages more sex with the right mate. And it is inconsistent and slow to arrive, not by accident, as in the vestigal hypothesis, but by design. And the sorting of men according to, let’s call it patience, seems to be a stable equilibrium as it requires either an exogenous characteristic correlated with “good genes” as in the case of dominant grizzlies, or perhaps in its social incarnation where it requires
sufficient access to resources to orchestrate interactions that are private, safe, and gratifying—in a word, romantic—and thus appealing to women’s evolved evaluation mechanisms.
From the book How Women Got Their Curves and Other Just-So Stories: Evolutionary Enigmas by David Barash and Judith Lipton. (Cloche Click: Bookslut.)
I collect examples of Kludges. Luis Rayo has sent me a very nice one.
In mammals, for instance, the recurrent laryngeal nerve does not go directly from the cranium to the larynx, the way any competent engineer would have arranged it. Instead, it extends down the neck to the chest, loops around a lung ligament and then runs back up the neck to the larynx. In a giraffe, that means a 20-foot length of nerve where 1 foot would have done. If this is evidence of design, it would seem to be of the unintelligent variety.
Apparently, some evolutionary biologists take this to be evidence of our fish ancestry.
“The circuitous path of the left recurrent laryngeal nerve in humans is evidence for their evolution from a fishlike ancestor… because the nerve remained behind this arch but still connected to a structure on the neck, it was forced to evolve a pathway that travels down to the chest, loops around the aorta and the remnants of the sixth aortic arch, and then travels back up to the larynx. The indirect path does not reflect intelligent design but can be understood only as the product of our evolution from ancestors having very different bodies.”
The latter quote is from “Why Evolution is True” by Jerry A. Coyne.
For the game theorists in the room, the difference must boil down to whether we have random matching across populations (case 1) or within a single population (case 2.)
Genetic evolution is a clumsy way to adapt to a changing environment. Our genes were presumably shaped by very different conditions than we face now. Why wouldn’t natural selection favor organisms who can adapt to current conditions and pass on these adaptations to their children? Wouldn’t we be more fit if Lamarck was right and if so, why was he so wrong?
Turns out he wasn’t so wrong after all.
This was the first evidence, now confirmed multiple times, that an experience of the mother (what she eats) can reach into the DNA in her eggs and alter the genes her pups inherit. “There can be a molecular memory of the parent’s experience, in this case diet,” says Emma Whitelaw of Queensland Institute of Medical Research, who did the first of these mouse studies. “It fits with Lamarck because it’s the inheritance of a trait the parent acquired. There is even some evidence that the diet of a pregnant mouse can affect not only her offspring’s coat color, but that of later generations.”
That is from an article in Newsweek on epigenetics. Here is more. And here is a blog about epigenetics.
This raises the theoretical question: if you were to design the system of inheritance, where would it be optimal to draw the line between those characteristics that should be hard-wired in genes and those that can adapt at higher frequencies? And wouldn’t that depend on the environment? So would the line be hard-wired or epigenetic? And which side of the line is that trait on?
And the same for food critics/wine tasters. Also, wine tasters generally drink in moderation whereas chefs and food critics have been known to carry a little extra weight.
In both cases, the choice of profession has revealed a taste for the respective delicacy. Winemakers love the taste of wine, chefs love the taste of food. And, as demonstrated by wine tasters, you can taste without consuming, and you can partake without consuming to excess. The wine tasters manage to achieve this but the chefs do not.
Evolution has given us taste as an incentive to acquire necessary nutrients. Pleasant taste is our reward for consuming. Presumably, sometimes we might prefer to consume less (maybe more) than what Mother Nature would prefer, so she gives us the sense of taste so that we internalize her preference. But we try to find ways to manipulate her incentive scheme and get this taste without consuming a lot, or even at all, viz. the wine taster.
Mother Nature is perfectly content to allow us to taste but not consume wine if we see fit. But when it comes to food, she insists that she knows better than us and she will not let us get away with just a nibble. As with the taste of wine, the taste of food draws us in, and we expect to have just a taste. But once the food is in front of us, the trap is set and she deploys her most powerful weapon: temptation that cannot be overcome.
An evolutionary explanation of time-inconsistency and a preference for commitment, a’la Samuelson and Swinkels.
I remember once thinking what an amazing stroke of luck it was that on the Earth there happen to be so many wonderful gifts for people to enjoy. For example, it seemed close to definitive proof of a benevolent God that tangerines were just hanging there from trees for us to pick and eat. Somebody had to understand us very well and care about us a lot to give us this delicacy for free.
Of course this is a fallacy. It was not the fruit that was designed for our taste buds but the other way around.
We need to be incentivized to consume whatever we need to survive. And there is no need to bring any Designer into the story because this can be taken care of by natural selection.
These points are nicely recounted in this TED lecture by Dan Dennett. However, he stops short of considering the plot twist in which we develop conscious thought and learn how to manipulate nature’s incentive scheme. It starts with nutra-sweet, vasectomies and pornography. That’s when the real game begins.
Most of us are “irrationally” afraid of snakes…but few of us are afraid of mushrooms. Since both can be potentially fatal and both can be good eating, this is puzzling.
Most of us are “irrationally” afraid of snakes…but few of us are afraid of mushrooms. Since both can be potentially fatal and both can be good eating, this is puzzling.That’s from “Information, Evolution and Utility,” a paper by Jeroen Swinkels and Larry Samuelson about why natural selection shaped our preferences the way it did. In their story, Nature accepts that there are things that we can learn that she hasn’t had time to program into us (like which mushrooms are safe to eat.) So instead of giving us a complete set of instructions for how to behave in every situation, she gave us beliefs and the instinct to experiment and learn. Then she lets us choose.
But there are somethings she knows better than us . For example that snakes will likely kill us. So, forseeing that these beliefs she has given us can, and often do, go astray, she builds in backup measures to stop us from acting on them in contexts where she is confident that she knows best. Hence irrational fears.
I think there is wide open arbitrage opportunity in behavioral economics to import ideas from principal-agent theory to explain why Nature (the principal) has given us (the agent) certain preferences (incentives.)
Cheap Talk 
