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July 19, 2004

The wisdom of Seinfeld

Here is a synopsis of an episode of Seinfeld titled "The Bizarro Jerry":

Elaine sets Jerry up with a friend who is very beautiful, but she has "man hands." George uses a picture of her and passes her off as his dead finance Susan; that gets him into the "Forbidden City" where high priced models hang out.

Remember that episode? Here is the IMDB profile for the actress whose picture George was showing around. The fact that such a hot woman ostensibly married George triggers something on other hot women, who now give him the time of day. In my own life, there was a girl at my high school who I will call "Tara." She dated the most popular guy in school in 8th grade. I would have rated the girl a "5.5," but inexplicably she had the status of a "hottie." In fact, guys would say she was hot, though further querying on my part tended to evince obfuscation on the issue from my peers.

It is with these obvious truths in mind that I came to reading The Imitation Factor: Evolution Beyond The Gene by ethologist Lee Alan Dugatkin. The author edited (and was a contributer to) the text Game Theory and Animal Behavior, which I also just read. The Imitation Factor had positve blurbs from Susan Blackmore (The Meme Machine) and Nancy Etcoff (Survival of the Prettiest), so that also got my attention. So what was the book about? If I had to sum it up: guppy see, guppy do!

Dugatkin's general thesis is that imitation is a behavior that can be expressed by extremely simple animals, in this case, guppies. In particular, he emphasizes the importance of imitation in sexual selection. It has been known in many species the females tend to prefer males that other females prefer. But how do you gauge the importance of this factor in comparison to genetic constraints?

There are a lot of experiments sketched out in The Imitation Factor, which in many ways reads like an extended review article aimed toward the lay audience, but the "titration experiment" with guppies stands out.

  1. Guppies from the Paria River in Brazil showed a heritable preference for bright colored males.
  2. When females were offered two males of the same intensity orange coloring, they randomly chose mates.
  3. The males were grouped differentiated between those who were 12, 15 or 40 percent orange in color, the females always chose the more orange male when there was a difference. This is a clear case of sexual selection (see The Mating Mind).
  4. But, the author contrived an experiment where there was an observer female who seemed to see another female choose the more drab male out of the pair.
  5. In this case, females chose the more drab male if the difference in coloring was moderate or small, but still followed their instincts and chose the bright male if the difference in coloring was large (for example, 12 vs. 25 percent orange might be small, while 12 vs. 40 percent might be a large difference).
The above experiment illustrated that an animal as "dumb" as a guppy is capable of imitative behavior (broadly defined), though these cues are restrained by instinctive constraints. There is more nuance to their conditioning though, as older females tend to ignore mate choice of other females if they have observed and are positioned to select between variant males, while younger females almost always will pick a mate based on what the previous female chose.

But what about people? The episode of Seinfeld that I cited above is an illustration of a truism. But Dugatkin recounted a psychological experiment that confirmed what we already knew, that people are highly influenced by the decisions of others. Male and female undergraduates were told about a fictious experiment. An individual that was stated to be unattractive was interviewed by 5 potentional dates. The test subjects were told that 4 out of 5 interviewers stated that they would date the individual that was already stipulated to be unattractive. After this, they were asked a variety of questions that would probe their own attitude toward dating the individual above, and evaluations of their character and personality. Interestingly, both men and women seemed to think the above individual must have been exceptional, with many positive traits, and many seemed to be willing to date the person, even though they were told the individual was not physically attractive. The main difference was that women assumed the individual must have been wealthy! The general tendency probably don't surprise anyone, but where does it come from? Is the "connecting of dots" in this fashion a product of reflective thinking? That is, using induction and deduction to derive a conclusion, or is it an instinct triggered by a mental module? Dugatkin does mention the "modular mind" in passing on the context of maladptive traits, but in general he stays away from deep cognitive issues to focus on behavior. Though I think the question is open, I suspect that the tendency for men and women to behave in such a imitative manner, illustrated above, has basic roots in the EEA. We don't mimic the preferences of others just because it is the most "rational" thing to do, rather, it is a human universal triggered by a "release mechanism" which is rationalized after the fact.

The author's main contention seems to be that ethology, the study of animal behavior, is much richer than many would assume, and that its applicability to human behavior is rather clear. The utility of imitation is obvious: it may require time & energy to gather information that might allow one to ascertain the genetic & physical fitness of a potential mate, and if one is in the presence of others who have those skills more sharply honed and are willing to unwittingly give pointers, then there is a strong inective to "go with the flow." Of course, this often amplifies conventional sexual selection and results in even greater reproductive skew and a smaller effective population (that is, a few males monopolize sexual access to females). "Go with the flow" has an affect on displayers as well, as the example of an Amazonian fish species where males copulate with parthogenetic females of another species just to impress their own females. Other recent popular books, like The Tipping Point, might have benefited from a more explicit exploration of animal behavior. Animals might give us clues into human fads and fashions, or more likely, the constraints upon our capricious cultural creativity.

If you want to explore further, I suggest you check out Lee Alan Dugatkin's publications (all in PDF format).


Dugatkin spends a lot of time contrasting his theory of imitative mate choice with four more directly genetic mechanisms:

  • Direct benefit, that is, the male that gives the female the biggest bundle of resources that increases her fitness and that of their offspring (the "good provider" model).
  • Selection for "good genes," which often (though not always!) boils down to The Handicap Principle. If the first type of mate choice is for "dads," this might be for "cads." The well publicized preference for symmetry would generally fall under this category as well (though symmetry ~ good health, so one would assume there might be some direct benefit too).
  • Runaway sexual selection, where female preference for a male trait and the trait in question are coupled together so that they ascend up a feedback loop. Runaway ornament diversity caused by Fisherian sexual selection has a full elaboration, and you can find the original mathematical exposition in R.A. Fisher's The Genetical Theory of Natural Selection.
  • Sensory bias, basically, animals have a bias toward certain colors or shapes because of environmental adaptations, and so potentional mates mimic similar variants to attract more attention. Pretty straightfoward.

Posted by razib at 10:59 PM