The Guardian has a review out of Cordelia Fine’s new book, Testosterone Rex: Myths of Sex, Science, and Society, which continues her critique of innate differences between male and female brains and behaviors. The Amazon summary includes this:
In Testosterone Rex, psychologist Cordelia Fine wittily explains why past and present sex roles are only serving suggestions for the future, revealing a much more dynamic situation through an entertaining and well-documented exploration of the latest research that draws on evolutionary science, psychology, neuroscience, endocrinology, and philosophy. She uses stories from daily life, scientific research, and common sense to break through the din of cultural assumptions. Testosterone, for instance, is not the potent hormonal essence of masculinity; the presumed, built-in preferences of each sex, from toys to financial risk taking, are turned on their heads.
Moving beyond the old “nature versus nurture” debates, Testosterone Rex disproves ingrained myths and calls for a more equal society based on both sexes’ full, human potential.
Now I can’t quibble with the last sentence, though I can say that we simply don’t know very much about evolutionarily-based differences in behavior between the sexes. I guess I’m an equity feminist, feeling strongly that members of both sexes (or of a spectrum of genders) must be offered equal opportunities and educations from the very outset: from birth. But if there are innate differences between genders or sexes, that won’t necessarily guarantee equality of outcomes. All we can do is ensure that nobody is discriminated against based on their genitalia, their chromosomes, or their own perception of gender.
I read Fine’s previous book, Delusions of Gender, and thought it was pretty good in taking apart some poorly designed experiments that themselves seemed to reflect the researchers’ ideologically driven agenda of hard-wired sex differences. But I also thought that Fine herself was at least partly motivated by ideology (the view that there are absolutely no behavioral differences between the sexes that don’t arise from social conditioning), and so my opinion of the book was mixed. In the end, I agreed with Diane Halpern’s take in Science on that book (Halpern also reviewed Brain Storm by Rebecca M. Jordan-Young, a book I did not read):
Cleverly written with engaging prose, Delusions of Gender and Brain Storm contain enough citations and end notes to signal that they are also serious academic books. Fine and Jordan-Young ferret out exaggerated, unreplicated claims and other silliness regarding research on sex differences. The books are strongest in exposing research conclusions that are closer to fiction than science. They are weakest in failing to also point out differences that are supported by a body of carefully conducted and well-replicated research.
I haven’t read Fine’s latest book, and so will address only the Guardian‘s take on it, which I find bizarre. One caveat is that it may be misrepresenting Fine’s views. But the quoted part below, which I’ve put in bold, suggests that the whole paradigm of sexual selection, and attendant behavioral differences between males and females, should be thrown out because of one flawed experiment:
Here’s one example Fine offers of Testosterone Rex mangling the way we think about sex. In the 1940s, biologist Angus Bateman conducted a series of experiments on fruit flies that appeared to show conclusively that competition between males for “fertile female vessels” was the driving force of evolution. The hypothesis goes something like this: laying eggs is a more substantial physical investment than producing sperm. Therefore, to maximise reproductive success, females should be selective and cautious while males should be promiscuous and competitive; therefore, women are domestic and monogamous, while men are thrusting away both in the public sphere and in as many beds as possible.
It’s elegant, it’s intuitive, and it’s wrong. Bateman’s experiments were biased by design and by his unexplained exclusion of data that, when included in a recent reanalysis, actually showed that males and females both produced more offspring when they had more mates. But there are limits to promiscuity as a strategy: taking into account female fertility, a man has more chance of being hit by a meteor than fathering 100 children with 100 different women in a year. The player who says it’s in his genes is missing a vital part of the story.
It’s true that Bateman’s experiment, purportedly showing that males had a much higher variance in mating success than did females—a crucial assumption of sexual selection theory—was flawed. This was pointed out in a PNAS paper by Patricia Gowaty et al., who noted that the use of certain mutations as genetic markers biased the outcome towards the sexual-selection hypothesis: that males are more promiscuous in mating, and females pickier, because females make a greater reproductive investment than males. But they didn’t say Bateman was flat wrong in seeing males more promiscuous than females; they said his results were “inconclusive.”
The Guardian‘s canard about the unlikelihood of a male fathering 100 children with 100 different women is simply misdirection: the question is whether some males get a lot of offspring compared to others (higher variance in reproductive success) while the variance among females is smaller. If that is the case, then there will be male-male competition—either direct or through display, ornaments, and so on—to woo discriminatory females.
In fact, Bateman’s experiment has been repeated properly in other species, with exactly the predicted finding of higher male variance and of males competing to fertilize scarce uninseminated females. To throw out the whole edifice of sexual selection (and I’m not using it to claim that “women are domestic and monogamous, while men are thrusting away both in the public sphere and in as many beds as possible”) because of one flawed experiment is to neglect the pervasive evidence from many areas that males are indeed evolutionarily adapted to try to mate as often as possible, while females are adapted to be more choosy. We don’t jettison an entire body of consilient evidence because one guy did a bad experiment.
Data supporting sexual selection, and a greater promiscuity of males rather than females, include the following:
- In human, primate, and many other animal species, males do indeed have a higher variance in reproductive success than do females (it’s been measured). It would be extraordinary if that was just a coincidence based on “social conditioning” in humans but evolution in all the other species that don’t have social conditioning.
- The theory of sexual selection is well worked out, and precisely explains this difference in sex-specific behavior.
- In species in which males make a greater reproductive investment than females, like seahorses and pipefishes (the males get “pregnant,” holding the eggs and young in pouches), we see the exact opposite of what we normally see. The males are choosy, while females, who produce eggs faster than males can accept them, are promiscuous. In fact, in those groups it is the females who are brightly colored and ornamented while males are drabber: the opposite of the normal situation, but exactly as sexual selection theory predicts.
- The difference in body size and strength between human males and females implies an evolutionary basis, almost certainly having something to do with male-male competition, as it does in many mammals, insects, and other groups (see my posts here and here). Holly Dunsworth, whose theories I’ve criticized, has never responded to my comments.
- Replicated experiments in both humans and other animals show a strong difference in promiscuity (in humans it’s done using experiments in which attractive strangers proposition people of the opposite sex). Again, it would be extraordinary if the parallel between human and animal behavior were purely coincidental.
- There is no convincing way to explain the pervasive existence of bright coloration, elaborate plumage (maladaptive for survival), calling and displays, and other “look-at-me” features of males versus females other than sexual selection. How that selection works may be enigmatic (do the male traits show good genes? good phenotypes? appeal to some innate preferences of females?)—but all of it supports the action of sexual selection.
- Bonobos (“pygmy chimps”), which may behaviorally more similar to humans than are “regular chimps”, have a fairly matriarchal society with more promiscuous mating of females than do other chimps, but still show a 25% greater body weight in males than females. Is that a holdover from an ancestor, or a byproduct of males competing for females? (After all, bonobo females are still saddled with pregnancy and child-rearing, and thus have far fewer potential offspring over their lives than do males.)
- Finally, insofar as the morphological traits are connected with differences in sexual behavior and proclivities of males versus females, it shows some genetic differences affecting behavior between the sexes—and differences that may rest largely in brain wiring. Now that needn’t reflect a difference in male versus female brain structure, as it could simply represent how brains that are identical produce different responses when affected by different hormones produced outside the brain. (Testosterone, for example, may trigger “promiscuous mating” genes that reside in both male and female brains but are activated only by male hormones.)
As I said, I haven’t read Fine’s latest book; what I’m reacting to here are the two bolded paragraphs in the Guardian summary—paragraphs implying (based on the flawed study of Bateman) that sexual selection simply doesn’t exist: it’s all social conditioning and the Patriarchy. But there are simply too many biological facts (first adduced by Darwin) to support that conclusion, not least the number of animals lacking a “patriarchy” who show strong evidence for sexual selection and sexual behavior resembling those of humans.
While some of those whom Fine has criticized may have distorted their science in the name of ideology, I worry that Fine is doing the same thing. I will find out when I read her book. But certainly the Guardian has engaged in scientific distortion in its article about Testosterone Rex.