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Sexual Selection and the Mind
A Talk With Geoffrey Miller

Jaron Lanier, Marc D. Hauser, and Joseph Traub on Sexual Selection and the Mind by Geoffrey Miller

From: Jaron Lanier
Date: 5-28-98

Let me first respond as a musician. Darwin did not invent the idea that attracting mates must have had something to do with the origins of music. Listen to the "locker room" talk of musicians and you'll frequently hear that theory articulated with hearty enthusiasm- and you can go back to a variety of ancient sources (Hindu, Chinese, and many others) and find approximations of the same.

Since it's very hard to define what is and is not music, I fear it's not an easily tested premise, but it is a welcome one. I am usually among the first to be offended by excessive reductionism in evolutionary theories of human nature, but this is the sort of idea that sits well. Of course music is in part a "spin off" of sex! I notice my own playing improve when women are listening. I suspect that effect is measurable and repeatable, and might provide one avenue for experimentation.

As I read Miller's interview, the difference I find with him is that he hopes to understand both music and sexual selection as more linear, contained, and measurable phenomena than I believe them to be.

Miller hopes to create dialogs where there have been divisions between disciplines. But there is a glaring chasm that he does not address. In a great many fields of inquiry, including biology, there has been a fascination for several decades with non-linear, chaotic systems, in which small changes cause effectively unpredictable results. And yet the human mind, which would seem to be the most apparent example of a such a system available to us, is still often stuffed into linear models by evolutionary psychologists.

Miller chooses the quality of intelligence to exemplify the practice of evolutionary psychology, so I will also use it to illustrate some room for difference in interpretation.

I fear there is an almost inevitable confusion of genetic traits (which are initial conditions for a brain) and capabilities (which are non-linear outcomes) in evolutionary psychology theories. I usually explain this with a metaphor to movie reviews.

It would be easy to come up with parameters to characterize and compare movies. One could speak of their budgets, the number of days in filming, the number of people involved in the production, and so forth. One could also find legitimate correspondences between these values. A movie production that makes use of a huge staff is likely to also require more days of shooting, for instance. It also possible to statistically link these parameters very approximately to the financial success of a movie. Analysts find that the most expensive and cheap movies are in general more likely to turn a profit, while mid-range budget movies are more likely to lose money.

So far so good. But these and other available measurements (such as focus groups) don't help much in predicting the success of an individual movie. "Titanic" was expected to be a flop, while "Godzilla" has turned out to be something of a disappointment. When it comes to judging the quality of a movie, as opposed to its market success, we can also find some general correlation between the various critics. If Siskel and Ebert both hate a movie, it's more likely the New Yorker reviewer will also hate it. But what is important is that in judging the overall quality of a movie, reviewers only suggest values with very low precision. Siskel and Ebert provide 2 bits of information (thumbs-up, thumbs-down), while other reviewers might offer a 4 or 5 star system, or, rarely, a ten star system. The measurements that can be made of a movie's production are much more precise than the evaluations of the "desirability" of the outcome, and can only be imprecisely correlated with precisely measurable outcomes, like profitability.

This all seems intuitive, yet when it comes to the human mind, an object of greater complexity, subtlety, and mystery than a movie, theorists are liable to confuse themselves by creating specious accuracy and correspondence.

There is a "G factor", and it is rather like the correspondence between a movies budget and its staff size and the number of screens on which it will open. This is a value that can be known to significant precision. There is also "intelligence" in the word's common usage and it is rather like a movie review rating. What I suspect, though, is that there is not a measure of overall quality of intellect or intelligence that is as accurate as G, and yet somehow psychologists uncritically assume that there is. Even worse, educators, employers, and parents are given no warning that there might be an illusion of specious accuracy in a testing system that directly effects the outcomes of individual lives.

Movie investors, and all of us, repeatedly fall prey to the illusion of linearity in non-linear systems. We still believe we can say someone with 110 IQ is ten points smarter than someone else with a 120 IQ, and studios still believe they can predict how much money a movie will make. Without this madness it is possible that movies would not be made, but science and parenting should try to rise above illusion.

(By the way, while I'm sure I have a G factor, I don't have an IQ - I have refused the tests since I was a child - filling them in randomly when forced to take them.)

While it is essential to explore the biological origins and constraints of human nature, it is ever more important to reaffirm that people cannot be entirely understood by those constraints.

The easiest way to demonstrate this is to point out that the advent of writing and civilization occurred during a period of practical genetic stasis. The human brain is clearly genetically capable of achievements which could not have been foreseen by the process of sexual selection, or any form of evolutionary pressure. Human traits have played out in unpredictable ways. This is almost too obvious a thing to state in so many words, and yet I feel a need to repeat it when I read the works of contemporary evolutionary psychology.

This is also the reason why it DOES make sense for Gould and others to treat humans as a special case, to some degree.

The joy of music is that it becomes more than we can account for, just like a brain or a movie. Yes, "Music is a system of basic elements, notes, that are combined according to certain principals of rhythm, tonality", but musical behavior is capable of extraordinary, non-linear flights of ecstasy and genius.

The illusion of linearity is demonstrated when Miller says, "It's going to be difficult for people to cope with ideas that there are just a few measures that can describe-not just their intelligence but their personalities." Indeed it should be difficult.

There is such a terrible danger of people confusing the squalid measurements of their parts with the demonstrated, non-linear grandeur of the potential of their whole.

I teach sometimes, and I will always consider it to be malpractice if I "relax" as Miller suggests, and ignore the possibility that genius might yet emerge from a "low G" student. I have seen it happen, and it is why I teach.

From: Marc Hauser
Date: 5-28-98

I would like to make just a few comments on the issues raised in your interview and discussion with Geoffrey Miller. First, I am completely sympathetic to the idea that there should be a marriage between behavioral genetics and evolutionary psychology. Steve Pinker is already doing this, using some of the intuitions derived from his account of language and its funcitonal design features, together with twin studies. Second, although there is an important historical distinction to be drawn between natural selection and sexual selection, and many behavioral ecologists continue to draw on this distinction, once you break the problem down into one focused on characters leading to fitness advantages (i.e., gene replication), the distinction really fades away. One looks at variation, heritability and fitnesses consequences. Third, although I am compelled by the arguments from evolutionary psychology, there are two areas of research that would, I believe, help in formulating hypotheses that are more atuned to mechanistic constraints. In particular, evolutionary psychologists need to know more about the brain, how it works, and the degree to which particular components of the brain allow for plasticity. Perhaps the most revolutionary findings within current neuroscience stem from work showing that even in adulthood, there is considerable plasticity (see, for example, the elegant work by Mike Merzenich on primates and rats, and the recent work by Ramachandran on brain damaged human patients or phantom limb victims). In addition, given the interest in a strong nativist stance, the recent explosion of work on hox genes seems extremely relevant. Given the fact that many genes for segmentation are highly conserved, we must be very cautious when we assess problems of homology and homoplasy, issues that would appear to lie at the heart of the evolutionary psychologist's claims for an EEA.


From: Joseph Traub
Date: 7-10-98

I've been traveling abroad so this reaction to Sexual Selection And The Mind by Geoffrey Miller has been delayed. I'll confine myself to a few comments.

1. Miller asserts that the two most desirable traits in a mate are kindness and intelligence. Is this just contemporary, or long-term? If contemporary, it doesn't provide an evolutionary explanation. If the claim (unsubstantiated) is that it's long-term, then why don't we see that kindness in human history?

As I was looking at the histories of the countries where I was recently (Greece, Turkey, Sweden, Denmark, Norway, Germany and France) I was struck by their savage histories: continuous wars, killings, sacking of cities and rapes, assasinations. If many generations have selected for kindness, why don't we see it?

2. Miller claims that 95% of our elaborate vocabularies are for courtship. My experience is that some grunts, moans, and monosyllabic words are sufficient in human courtship.

3. His next research project is to show that vocabulary size is a good indictor of intelligence. I don't doubt that's true, but how does it advance the primary thesis that we choose mates for intelligence?

4. Miller ssays that the biologists who shy away from his ideas suffer from a failure of nerve; they just want to keep getting their grants.

Now that's not very kind.

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