Lloyd

When Harry met Sally, he discovered that, in fact, women can do a pretty convincing job of "faking it." Now, Elisabeth Lloyd, a professor in the IU Bloomington Department of History and Philosophy of Science, is accusing some evolutionary biologists of being fooled in much the same way that Harry was.

In her new book, The Case of the Female Orgasm: Bias in the Science of Evolution, Lloyd makes the claim that scientists have allowed themselves to believe what she labels as "incredibly bad science." Specifically, she says that the belief that the female orgasm is an adaptation is just not supported by the evidence to date.

(Editor's note: An excerpt from the book discussed below may be read online at this Harvard University Press Web site. The book was published in April.)

According to Lloyd, the facts just don't add up. In order to claim that a trait, such as orgasm, is an adaptation, the trait should be found widely in a species. But this is just not the case with the human female orgasm. In fact, best estimates reveal that orgasm occurs during intercourse in females at a rate of approximately 50 percent at best. In her new book, Lloyd lays out the case for a bias in evolutionary biology that has led to a misreading of these facts. While the book has been released by Harvard University Press, the story dates back to a conversation between colleagues more than 20 years ago.

Back in 1984, a friend asked Lloyd about the evolutionary function of the female orgasm.

Lloyd explained that she was certain that there would be a simple adaptationist explanation and promised to look into it and get back to the friend. Instead, what she discovered was what appeared to her to be a mass of contradictions. On the one hand, she uncovered more than 20 studies in the sexology literature, including evidence in the 1953 book by IU sex researcher Alfred Kinsey, which claimed that the female sexual orgasm was a less than a reliable event, yet, on the other hand, she discovered that people today believe a purely adaptationist explanation for the existence of the female orgasm.

The adaptationist explanation goes something like this. The contractions of the female reproductive tract that accompany orgasm increase the likelihood that sperm will be drawn up further into the uterus and fallopian tubes, thus increasing the probability that the sperm will, in fact, meet the egg. This theory has been rather crudely labeled the "sperm upsuck" theory. Since this explanation credits the female orgasm with increasing fertility, it logically follows that nature has selected for this trait. But in her book, Lloyd makes the claim that this explanation is fraught with problems.

"Here I was, just looking up something for a friend, and I ran into this truly bizarre case where the evolutionists actually gave an adaptive explanation for something while at the same time citing the literature that made their explanation false." —Elisabeth Lloyd

Says Lloyd: "Here I was, just looking up something for a friend, and I ran into this truly bizarre case where the evolutionists actually gave an adaptive explanation for something while at the same time citing the literature that made their explanation false." She goes on to say that "to a philosopher of science this is an intriguing thing because good scientists don't usually do this."

According to Lloyd, the unreliability of the female orgasm is the piece of the puzzle that just does not fit. In order for a trait to have been selected for, she says, it should occur most of the time.

However, all the data on the frequency of orgasm in the females of the human population tell us that female orgasm does not even occur half of the time during intercourse. In fact, according to data collected by Kinsey and others, some women, perhaps up to 10 percent, never experience orgasm at all, while another 20-25 percent of women almost always experience orgasm with intercourse. Still, that leaves the vast majority of women who may or may not experience orgasm during any given act of intercourse. As Lloyd explains, "you wouldn't call a car reliable if it only started 50 percent of the time."

The only explanation that Lloyd uncovered that did seem plausible to her was that of Donald Symons, an anthropologist, now retired, from the University of California, Santa Barbara. Symons suggests that the female orgasm is just an artifact of embryology. Symons' theory is that the female orgasm is not an adaptation, but is in fact a result of strong selection for male orgasm.

During the development of the human fetus, there is a point when the gender will be determined. Specific cells will either go on to form the penis, if the fetus is a male, or the clitoris, if the fetus is a female. Symons makes the claim that since the same tissues are involved in male orgasm and female orgasm, it would appear that those females who do experience sexual climax merely do so as a by-product of nature's choice to perpetuate the ability of males to do the same. In other words, the sensitive tissues of the male penis are necessary for the human species to perpetuate itself, for without the male orgasm, the sperm would never make its way to the egg. While these same tissues allow for female orgasm, Symons does not believe that female orgasm is necessary for reproduction.

In fact, Symons and Lloyd firmly reject the "sperm upsuck" theory which was originally based on one study of the orgasms of only one woman who was regularly orgasmic. A later, widely touted study claimed to confirm the earlier study's findings, but, as Lloyd discovered, not only was this study poorly designed, the statistical analysis was abysmal. Lloyd said that she took the study to an objective group of statisticians, and they remarked that the analysis "would not pass a test in Statistics 101."

Nonetheless, Lloyd emphatically states that she is not, in principle, opposed to or in favor of an adaptationist explanation and is perfectly willing to "wake up tomorrow and discover that the female orgasm is in fact an adaptation."

Why write a book?

Lloyd insists that her motivation to write this book was to explore why "such incredibly bad science became so widely believed despite the fact that it was so deeply unscientific." Overall, she believes that there were many biases at work, but she feels that the most influential bias was the one in favor of adaptationism or the belief that if a trait exists, it must have been selected for at some point in the history of the organism.

To a biologist and philosopher of science, this ability to fool a vast majority of the scientific community and get away with it was so intriguing that Lloyd felt compelled to expose what she characterizes as an almost fundamental zeal to further the adaptationist position on the birth of the female orgasm.

Lloyd explains that, while there are many excellent scientists who are adaptationists, those involved with the case of the female orgasm were incredibly irresponsible in gathering their evidence and somehow managed to convince a large segment of the community of evolutionary biologists that they were correct in their conclusions about the adaptive nature of the female orgasm. To a biologist and philosopher of science, this ability to fool a vast majority of the scientific community and get away with it was so intriguing that Lloyd felt compelled to expose what she characterizes as an almost fundamental zeal to further the adaptationist position on the birth of the female orgasm.

Lloyd refuses to characterize other cases of applied adaptationism as bad science and is focusing solely on the case of the science of the female orgasm. Nonetheless, she predicts that some scientists will accuse her of an anti-adaptationist stance. Indeed, she predicts she will be "skewered," not just by adaptationists, but by others. As she said in February before the book was released: "Everybody involved in the debate is going to hate this book—not only do I attack all the adaptationists, I criticize everyone who has ever written on the subject, and I criticize all feminists except one who has ever written on this subject—so the feminists and adaptationists alike are going to hate it."

Everybody involved in the debate is going to hate this book—not only do I attack all the adaptationists, I criticize everyone who has ever written on the subject, and I criticize all feminists except one who has ever written on this subject—so the feminists and adaptationists alike are going to hate it." —Elisabeth Lloyd

John Alcock, a professor of animal behavior at Arizona State University, may not hate it, but when asked to comment on the premise of Lloyd's upcoming book, he acknowledged that many people have raised the issue of the inadequacy of the adaptationist explanation based on the less than 100 percent occurrence of the female orgasm with intercourse. But, he said, "for the life of me, I do not understand the logic of the argument. When we eat a high-priced meal at a restaurant, we are not guaranteed to go into ecstasy over the foods consumed, but the ability to evaluate foods is surely adaptive because this ability enabled our ancestors to analyze the nutrient content of the foods available to them."

Along that same vein, Alcock argues that "women can use their resistance to orgasm to evaluate partners, finding really good ones emotionally and sexually more satisfying than indifferent ones." In other words, if females have evolved to be able to be selective about orgasm, then they will more likely be able to procreate only with men who are able to bring them to climax. This argument rests on the "sperm upsuck" theory because it assumes that orgasm leads to a higher likelihood of fertilization of the egg.

Alcock argues that it is completely logical to assume that male and female orgasms would be different. After all, a male who only rarely had an orgasm would limit his opportunities to procreate. On the other hand, it is assumed that a woman is likely to have adequate opportunities for sexual encounters; therefore, her ability to choose to have an orgasm or not have an orgasm would enable her to choose the more desirable mates to father her children.

Of course, the logical next step of this argument is that males who are better able to satisfy their mates would be more abundant in the population simply because their sexual encounters would be more likely to result in pregnancies. Eventually, these males who are more capable of provoking orgasm in their mates would become more and more prevalent because they would be reproducing more frequently and passing their "expert lover" genes to their male offspring.

So the question remains—if this theory is true, why are Sally and so many other women still faking it?

Editor's note: Allspaw is a former middle school science teacher and is currently working on her Ph.D. in science education at IU Bloomington. She is originally from Indianapolis, but recently lived in Massachusetts where she completed a master's degree from Tufts University concerning animals and public policy. She wrote the above feature for a science writing class this spring taught by Holly Stocking, a professor at the IU School of Journalism in Bloomington.