Mormonism LIVE: 066: David Bokovoy – Sex, Eden and The Family

Bill and RFM:

First, I want to congratulate on your impressive body of work and thank you for the many wonderful podcasts you have put out. I know how much effort goes into preparing, recording, and editing such high-quality content, and you guys consistently do a solid, professional job at it.

I think there is some important context and information to add to what was talked about in this podcast.

Much of the discussion about sexuality was based on the book Sex at Dawn>. Unfortunately, that book has serious flaws and is widely rejected by scholars.

For example, Oxford University Press (OUP) was initially set to publish Sex at Dawn, but OUP eventually rejected it because the book failed OUP’s peer review process (starting at minute 14 of this podcast, Sex at Dawn author Christopher Ryan talks about this). The book was eventually published by Harper, a non-academic press that does not require rigorous peer review.

Most scholarly reviews of the book have been negative. Noted evolutionary psychologist Steven Pinker called Sex at Dawn “pseudoscience.” And this review in Evolutionary Psychology (a peer-reviewed academic journal) by Ryan Ellsworth talks about Sex at Dawn‘s “many, many misunderstandings, errors, omissions, and perhaps intentional mistreatment of the ‘evidence’ of our ostensibly promiscuous sexual nature, but also an ideological agenda buried in the mire of shoddy science.” That entire review sets out a number of compelling critiques of Sex at Dawn, and the whole thing is worth reading, but one important and particularly relevant point it makes is this: “[p]air-bonding and marriage are cross-cultural universals, something that … Dawn does not even attempt to account for…. The fact that marriage has been recorded for even those foraging societies that had previously been unaffected by agricultural contemporaries at the time of first contact means that any explanation of marriage and pair-bonding that attributes these traits to the consequences of an agricultural mode of subsistence is simply untenable. The absence of any explanation for long-term monogamous or polygynous mating arrangements across non-agricultural human societies is a big hole in the Dawn story that Ryan and Jethá apparently felt no need to address.”

Psychology professor David Barush, who is an expert on human sexuality, described Sex at Dawn “as an intellectually myopic, ideologically driven, pseudo-scientific fraud…. [w]ritten by people who don’t know diddly-squat about evolutionary biology” that displays “a profound misreading of not only bonobo (‘pygmy chimp’) sexuality, but what, if anything, this implies for Homo sapiens.” He goes on to write that the authors “ignore and/or misrepresent reams of anthropology and biology in their eagerness to make a brief for some sort of Rousseau-ian sexual idyll that exists—and/or existed—only in their overheated libidinous imaginations.”

In the textbook Evolution & Human Sexual Behavior (by Peter B. Gray and Justin R. Garcia and published by Harvard University Press), the authors say that Sex at Dawn is “terribly misleading” and
that it “pursues a cause the evidence doesn’t support.” (p. xv).

The book Sex at Dusk is a refutation of Sex at Dawn, and has been endorsed by many of the above scholars (Pinker, Barush, and Ellsworth). I suggest reading it for a more scientifically sound
view.

Another point of discussion that came up several times in the podcast was explanations about human evolution based on group selection, which is the idea that traits can evolve because they help the survival of the group. The concept of group selection in humans is not accepted by most mainstream evolution and genetics scholars because no one has explained a satisfactory mechanism for how group selection could work in humans in most circumstances. This is because natural selection in humans works through individuals, not groups. If an individual carries a certain gene that increases the chances of his group’s survival, that gene will only get propagated to the next generation if that particular individual successfully reproduces and leaves behind offspring carrying that gene. Thus, a gene can only get passed on to the next generation if it confers a selective advantage on the specific individual carrying that gene. Whether or not it helps the group is thus largely irrelevant. What matters is the selective advantage (or disadvantage) that the gene confers on the individual–the gene has to directly make that individual more reproductively successful. If a gene is good for the group but does not lead to increased reproductive success for the individual, then it will not increase in frequency in the population. If it is good for the group but decreases the individual’s reproductive fitness, then that gene will eventually disappear, no matter how big of an advantage it confers on the group. There are some simple equations that scholars use to measure the selection for a trait over time, and the math for group selection just doesn’t work out. Only a very small minority of scholars support group selection, and they have been unable to back up their claims with evidence of it actually happening in humans, and have been unable to convincingly demonstrate mathematically how such group selection could occur.

In the podcast, one specific idea that was discussed was that homosexuality could have evolved because it was beneficial for the group. Evidence for this theory is lacking. The most common version of this type of theory is what is sometimes called the “gay uncle theory,” which is a claim that homosexuality could have evolved and been selected for because homosexuals would help care for their nieces and nephews, and thus help more of them survive to adulthood. On average, though, uncles only share about 25% of their DNA with their nephews and nieces, whereas parents share 50% with their children. Thus, a gay uncle would have to be more than twice as effective as the mother herself at raising extra nephews/nieces for this theory to work out mathematically. A trait that confers a reproductive advantage that more than doubles another person’s reproductive success would have huge effects and likely need to cause large and obvious differences in behavior that would be easily observed and measured. For example, if the “gay uncle theory” were true, we would likely expect to see gay uncles putting in more than twice as much parenting effort as the nephew’s/niece’s own parents. It should be easy to find evidence of this big of an effect, but there is none.

The math just doesn’t work out for the “gay uncle theory” and other types of group selection explanations for homosexuality in humans. In fact, there is not much evidence at all for genetics being a major explanation for homosexuality. Rather, the heritability for homosexuality is quite low (heritability means the variance in outcomes that can be explained by heredity; for example something that is completely determined by genetics would have a heritability of 1, or 100%). Among identical twins, when one twin is homosexual, only about 25% of the time is the other twin also homosexual. If homosexuality were completely heritable, we would expect this number to be much closer to 100%. Scholars who have crunched the numbers using large datasets have found that, overall, the heritability of homosexuality is a relatively low .22 (or 22%). And they have concluded that this .22 figure is likely an overestimate, and the real number is probably closer to .11 (see this paper from the Journal of Human Sexuality). If homosexuality were mostly caused by genetics, we would expect its heritability number to be much higher (for example, the heritability of intelligence is between .50-.80).

Finally, in future discussions of this type, I suggest you consider also discussing the is-ought problem and the naturalistic fallacy. Just because something is natural, it does not mean it is good. For example, there are many criminal behaviors that are universally condemned today (such as murder, theft, and rape). These behaviors are “natural” and observed among our close primate relatives. Even war and genocide are “natural”–chimpanzee troops will go to war against each other, and, if given the chance, will entirely eliminate rival troops. But just because these behaviors are natural, it does not mean that they are good or desirable or moral. Furthermore, just because some behavior is natural, it does not mean that it will bring the greatest meaning and peace to one’s life.