Science is our best way of getting to know the realities of the natural world—indeed, I am prepared to argue that it is our only reliable way. (If there are still any retro, postmodernist ideologues out there, claiming that the natural world lacks reality independent of our subjective “cultural narratives” and the particular world-view that we happen to “valorize,” I’m prepared to argue with you, too!)
Most of us look to science for answers, if only because to a remarkable degree, it provides them. And so, not surprisingly, nearly every book or course dealing with science talks about what we know … which is something of a shame, because the greatest delight of science, and what keeps me coming back to it, is what we don’t know.
As for identifying (and ultimately, solving) scientific mysteries, one of the richest arenas is evolutionary biology—that of human beings in particular. I have been thinking a lot recently about such mysteries; in the future, as the spirit moves me, I’ll nip about the ankles of some of these mysteries—at least until I get it/them out of my system.
One of the most intriguing scientific unknowns is homosexuality. Indeed, when Winston Churchill described the Soviet Union in 1939 as “a riddle wrapped in a mystery inside an enigma,” he could as well have been talking about homo-erotic preference.
Dean Hamer is an enterprising geneticist who raised quite a fuss some years ago when he announced the discovery of a “homosexuality gene,” and who subsequently claimed yet another one, this time for belief in God. (His next finding might well be that God is really homosexual, or perhaps the existence of a gene for discovering genes.) Although Hamer’s homosexuality gene hasn’t proven to be the slam-dunk that was originally hyped, there is growing conviction that the genetic underpinning for same-sex preference is real. Why? Among other things, not only does homoerotic preference run in families, but monozygotic (identical) twins have a higher “concordance rate” for homosexuality than do dizygotic (“fraternal”) twins, which in turn, are more likely to share homosexuality than are half-sibs, followed by unrelated individuals chosen at random.
Hence, the mystery. Insofar as there is some genetic basis for homosexuality, then—as with another favorite evolutionary conundrum, altruism—natural selection should operate against such a tendency. After all, there are strong data that homosexuals on balance produce fewer offspring than do heterosexuals.
And so, evolutionary biologists eagerly looked for evidence that homosexuality—like much animal and human altruism—is underwritten by kin selection: the process whereby genes prosper by benefiting identical copies of themselves in other bodies.
It didn’t pan out.
For starters, compared to heteros, homosexuals did not appear to spend an especially large amount of time helping, or even interacting with, their relatives. Also, it is noteworthy that—specifically in modern, Western societies—parents do not generally react with delight when they learn that a child is gay or lesbian, whereas if homosexual children were analogous to, say, the “helpers at the nest” phenomenon among birds (whereby non-reproducing older sibs help their parents rear a subsequent brood), we might expect tolerant acceptance if not outright enthusiasm on the part of those expecting help.
But it is now beginning to look like the death of kin selection as an evolutionary explanation for homosexuality—as Mark Twain famously responded to the announcement of his own demise—has been greatly exaggerated. Thus, the unremarkable levels of intra-family benevolence earlier reported for homosexuals were based on technologized, 20th-century populations, which might not reflect the long period of small-scale, nontechnological hunter-gatherer living during which such tendencies would presumably have evolved. And in fact, some interesting and suggestive research has recently emerged, focusing upon male homosexuals among a traditional population on the island of Samoa.
Known as fa’afafine, these individuals do not reproduce. They are, however, fully accepted into Samoan society in general, and into their kin-based families in particular. Of particular note is that fa’afafine are significantly more prone to behave in a positive avuncular manner than are heterosexual uncles. Thus, they are more likely to purchase toys for their nieces and nephews, to babysit, contribute money for the children’s education, and generally provide high levels of indulgence and emotional support, in addition to their material assistance. This supportive role of fa’afafine also exceeds the contributions of heterosexual women as supportive aunts.
One effect of modernization worldwide has been a reduction in infant mortality and a parallel decrease in average family size, the so-called “demographic transition.” A consequence of this, in turn, might well be that with fewer children per family, the industrialized world offers less opportunity for homosexual offspring to convey benefits to their heterosexual siblings, simply because there are fewer of the latter. Add to this the fact that with enhanced mobility, it is increasingly common for individuals to leave their nuclear family to attend school and eventually start their own, separate domestic lives.
Hence, it is possible that kin selection was involved in the initial evolution of human homosexuality, although little or no fitness payoff is currently detectable, except in traditional societies. It may also be significant, therefore, that unlike the experience of gays and lesbians in much of the industrialized world, fa’afafine are fully integrated into Samoan society and are definitely not discriminated against.
The implications are potentially large, and not only for a deeper scientific understanding of how and why homosexuality may have evolved. Thus, if—as could well be the case—homosexuals are only able to employ their kin-selected inclinations to benefit their straight relatives under conditions in which homosexuality is tolerated, even encouraged, then what is maladaptive these days is discrimination against homosexuals rather than homosexuality itself.
(Sorry this post is so long! I promise: Future ones will be more succinct.)
30 Responses to The Love That Dares Not Speak Its Evolutionary Basis
t_paine - November 25, 2010 at 3:11 pm
Small Point:
Nothing is maladaptive except from the point of view of someone invested in a certain status quo, real or imagined. If you like the way things are, any change can seem maladaptive. If you have an idea about how things are supposed to be, reality may not cooperate, and thus earn your ‘mal’ rating and expose your biases.
You write from the point of view of a single species, human, of a progressive who is very P.C., with a narrow social agenda, and you are damn well going to make the science confirm and conform.
I’m sure you have more to reveal about War, Oppression, Hegemonies, Animal Cruelty, Climate Change, Racism, etc.,all from the Activist Utopian Evolutionary Biologist’s vantage point.
You’ve given them homophobes the what for, biologically speaking. They’re being mal. Adaptive.
Next week it’s War (HUH!) What is it good for?
goxewu - November 25, 2010 at 4:42 pm
Re t_paine:
“Nothing is maladaptive except from the point of view of someone invested in a certain status quo, real or imagined. If you like the way things are, any change can seem maladaptive. If you have an idea about how things are supposed to be, reality may not cooperate, and thus earn your ‘mal’ rating and expose your biases.”
Hmm. Sounds an awful lot like an example of…
“Post-modernist ideologues out there, claiming that the natural world lacks reality independent of our subjective ‘cultural narratives’ and the particular world-view that we happen to ‘valorize’.”
t-paine sure surprised me.
(The turkey’s taking longer than expected to be fully cooked.)
t_paine - November 26, 2010 at 12:55 am
You seem a bit out of your depth with this one, Goxewu, but no matter. Have a nice holiday.
nordicexpat - November 26, 2010 at 1:30 am
This is a bit OT, but I’ve always found positions taken by evolutionary psychologists on contemporary social and political issues to be somewhat contradictory. Sometimes, they appear to say that claiming that something was adaptive back in the Pleistocene era is not the same as justifying that behavior. They stress we need to recognize the power and influence of these evolutionary mechanisms in order to better resist them, since those impulses may now be maladaptive, socially undesirable, morally repugnant, etc. (at times, I think this is the evolutionary psychology equivalent of original sin, but that is perhaps unfair characterization). At other times, evolutionary psychologists appear to claim that we need to accept these evolutionary mechanisms as “natural” and beneficial. While Barash doesn’t come out and make this argument directly, he seems to imply as much in his final paragraph. But maybe I misunderstood his point?
Personally, I am against all forms of discrimintion against gays and lesbians. Still, I wonder whether an understanding of how homosexuality may have evolved really does have any larger implications for social and legal policy today. (Outside, of course, of countering scientifically false claims about homosexuality).
goxewu - November 26, 2010 at 8:25 am
“You seem a bit out of your depth on this one.” That’s nicely boilerplate, and could be applied as a generalized insult, by most any commenter to any comment with which he or she disagreed. t_paine is usually better than this.
dpbarash - November 26, 2010 at 11:50 am
Thanks, nordicexpat, for pushing me to clarify: I feel strongly that there is no necessary connection between whether a trait is adaptive and whether it is socially desirable, worth defending, etc. Adaptive means “contributing to success in projecting genes into the future,” no more and no less. Maladaptive means working in the opposite direction. Although my last paragraph could certainly be taken as making a policy point, it simply says that examined strictly from the perspective of adaptive-versus-maladaptive, and independent of any social policy considerations, it is increasingly likely that homosexuality is adaptive and discrimination against gays and lesbians, mal-. Food for thought, I think, if only because it goes against conventional wisdom.
t_paine - November 26, 2010 at 4:12 pm
The ‘traditional’ societies you mention in which homosexuality was useful have or are fading away. Societies where there is conflict or intolerance over homosexuality dominate and out- reproduce them.
Parallel to the traditional societies you mention are many others, contemporary with them and equally ‘traditional’ which are still very much viable: the Arab-Islamic forms for example, in which homosexuality is not encouraged.
Please explain this, in relation to your …”contributing to success in projecting genes into the future,” no more and no less. Maladaptive means working in the opposite direction.” if you can.
blog21 - November 29, 2010 at 8:44 am
Not at all a useful article. I also find these kinds of thought patterns to be QUITE post modern. A few (very few) facts, laced together into a narrative that “works” for the author. What could be more post modern than that?
11182967 - November 29, 2010 at 9:50 am
Here’s a thought for further research. The article notes that the Samoan uncles do not reproduce. But in a society in which homosexuality is condemned or repressed it may be more likely that gay men marry and father children in the guise of straightness. Has any research been done on the relative frequency of homosexuality in societies as a function of the likelihood that gay men father children? The issue (so to speak) of gay women reproducing might be a little more complicated. In a repressive or simply male-dominated society gay women may by married off and reproduce at the same rate as other women. In a more permissive society, however, they may more commonly reproduce while remaining single or as part of a same-sex partnership. Some sort of analysis of these variables ought to tell us something about the “natural rate” of homosexuality–whether or not it is affected by social factors. On the other hand (again, so to speak), I’ve read that a number of “odd alternatives” in human populations, such as left-handedness and homosexuality seem to occur at similar rates (ca. 11%), so there may be some more overarching principle operating here.
jcisneros - November 29, 2010 at 10:39 am
I am simply not academically qualified to comment on the content of this article. I will say that I do not find myself terribly comforted by the line of reasoning used.
Modern sexual orientation studies seem to invariably have a built in bias, whether the study in question aims to prove that orientation is a genetic predisposition or a “choice.” Alternatively, there is a lot of junk science out there that asserts homosexuals may be “cured” by some sort of magic therapy (usually sccompanied by a strict regimen of prayer).
I am less comfortable with the attitudes of some of my colleagues and the snide remarks of supposedly educated commentators on same-sex orientation in general. The Ivory Tower is less liberal in regard to same-sex orientation than folks would think.
~JC
dank48 - November 29, 2010 at 10:47 am
It’s more complicated than it might seem at first. In fact, it’s more complicated than it might seem even after a lot of study. Reality is like that.
Homosexuality seems to me one of those subjects, like theology, in which most people seem to feel that one opinion is as good as another, never mind the science or the existing body of writing that they don’t bother to read. Like the evangelist in the Thurber fable who had done well by “dragging God down to man’s level,” so it is with those who prefer a simple answer to a complex question adequate, no matter how wrong it may in fact be.
Imo Gore Vidal got it right years ago when he wrote than in less than a century, homosexuality has gone from the love that dare not speak its name to “the love that won’t shut up.” As a subject, it’s interesting and important, but it’s not nearly so interesting or important as some people think. And it seems to me that this applies equally to the extremists at both ends of the spectrum, who generally produce far more heat than light.
cbres - November 29, 2010 at 11:02 am
First, JC is right with his last sentence.
Second, when I read a piece about this topic, my first question is about the vocabulary used. When the author writes about “same-sex preference,” I take careful note (and this piece is about whether there is an identifiable genetic link to same-sex orientation!). Those words are the choice of the right, which insists that we choose the gender to which we’ll be attracted. I have yet to meet a straight person who thinks s/he is straight by preference, but straight people frequently assert that gay people choose (or ‘prefer’) to be gay. So, consider this a teachable moment, kind author: please review your word choice and consider the multiple meanings behind them.
jcisneros - November 29, 2010 at 7:12 pm
Cbres, I am not certain “kin selection” is a viable argument, but since I am a social scientist, not an evolutionary biologist, I will bow to wiser heads than mine. But I do know that being told I (or other gay men) made some sort of a conscious, considered choice of male genital contact for intimacy (and thus eschewed the heterosexual “norm”) irritates me…and I am certain the blog author meant no harm by his word choice. Yet, I do believe he should have chosen his words more carefully. The whole “choice” argument seems to be rubbish.
For those interested in this question in depth should consider reading Joan Roughgarden’s “Evolution’s Rainbow” (U California Press, 2004).
~JC
BaiGanyo - March 24, 2011 at 6:45 am
I’m sure some Americans will find a way to spin this into a human rights issue somehow.
no66am - May 15, 2012 at 3:40 pm
”
Lehrer’s defense is that he is fully aware that, as he puts it, “our current science is very much a first draft,” but that you can’t weigh down every example with a page full of caveats and expect a normal person to read it on an airplane” ….. I think this is a weak argument: the late Stephen Jay Gould used caveats wherever they were necessary to indicate that a hypothesis or set of arguments were provisional or open to question; he was read with great intensity on airplanes and pretty much everywhere else. He would have had plenty to say about those blue walls: that’s a claim that truly demands to be weighed down with caveats.
schultzjc - May 15, 2012 at 8:53 pm
This is indeed a long-standing issue for communicating science to the public: how much detail is necessary to be “correct”? And does it matter if details are incorrect? To the first I answer “not much”. The level of detail a scientist demands for assurances is way more than necessary to get most points. You don’t need to know calculus to understand that things can’t go faster than light.
To the second I answer, it does matter, but not for understanding’s sake. Most people don’t understand variation, uncertainty, or even replication, but they do understand “being wrong”. Authors like Lehrer risk general disbelief – of everything – by being called out. If he’s wrong about blue walls, what else in the book, or even the science, is false? (As a scientist as well as normal person, I think the ‘blue wall’ conclusion is excessive generalization.) Scientists and science are likely to be painted with the same blue brush in many people’s minds.
Of course, if no one notices until someone like Chabris point out such errors, maybe it won’t matter much. Perhaps we should just prohibit scientists from reading and reviewing each other’s popular works.
schultzjc - May 15, 2012 at 8:53 pm
This is indeed a long-standing issue for communicating science to the public: how much detail is necessary to be “correct”? And does it matter if details are incorrect? To the first I answer “not much”. The level of detail a scientist demands for assurances is way more than necessary to get most points. You don’t need to know calculus to understand that things can’t go faster than light.
To the second I answer, it does matter, but not for understanding’s sake. Most people don’t understand variation, uncertainty, or even replication, but they do understand “being wrong”. Authors like Lehrer risk general disbelief – of everything – by being called out. If he’s wrong about blue walls, what else in the book, or even the science, is false? (As a scientist as well as normal person, I think the ‘blue wall’ conclusion is excessive generalization.) Scientists and science are likely to be painted with the same blue brush in many people’s minds.
Of course, if no one notices until someone like Chabris point out such errors, maybe it won’t matter much. Perhaps we should just prohibit scientists from reading and reviewing each other’s popular works.
11119482 - May 16, 2012 at 12:05 am
“knows more about science than a lot of scientists.” Depends on how we define scientists. If we define them by those who seek to ask questions and challenge hypotheses and conclusions through experimentation, maybe this is a problem. But if we include those who have degrees and positions suppposedly as “scientists.” he might well know more science than many who call themselves scientists. Too many ‘scientists’ are technicians primarily and not natural philosophers. In other words, very narrow in understanding and viewpoint. So depends on what meant by “scientists.”
nontraditional001 - May 16, 2012 at 9:07 am
accuracy and completeness keep science out of reach of the layperson, we need writers who can distill the information into broadly digestible fare. I can see a critic making sure facts are straight, but asking a writer to include every possible permutation should be saved for a dissertation.
chedie - May 16, 2012 at 10:13 am
This was not a dissertation. That does not excuse the author completely, but this arrogant witch hunt by a jealous critic is unwarranted and unhelpful. We need people relating complex science to the layperson, and Lehrer does this quite well. Report his major errors, allow a response, and let it go.
3rdtyrant - May 16, 2012 at 10:24 am
Right. On Star Trek the writers will throw in the occasional scientific term to explain some phenomenon, and I don’t see how imprecise scientific writing, as engaging as it might be, is any better than an episode where Captain Kirk fights an energy being named Melvar.
3rdtyrant - May 16, 2012 at 10:29 am
Exactly the point, I think. Our students do not benefit from this kind of thing. I had this debate about Seamus Heaney’s translation of Beowulf, which is vastly inferior to many other translations. However, it popularized Beowulf immensely. My colleague was convinced that this was the highest good for Beowulf. My argument was that the quality of the translation mattered more than its popularity. Similarly, scientific writing that reaches a popular audience might get the word out about something, but if that word is incomplete or inaccurate, we create more problems than we solve.
3rdtyrant - May 16, 2012 at 10:33 am
Agreed. Lehrer should be jealous of Chabris.
3rdtyrant - May 16, 2012 at 10:38 am
Might it be more valuable, rather than dumbing down science for lay people, for lay people to smarten themselves up to understand science and scientific writing? Understanding is as much a measure of the audience as it is the writer, and I don’t see a down side to a lay audience understanding complex and qualified arguments, even if badly written. The up side is that they recognize bad writing and good facts and then move forward improved, informed, and ready to engage the next idea, rather than have the next idea fed to them in a twinkie.
pflady - May 16, 2012 at 10:40 am
Can’t you have good writing and correct information?
nontraditional001 - May 16, 2012 at 11:50 am
I’d save the gritty details for the footnotes for the more intrepid readers
Steve Shoe - May 16, 2012 at 12:47 pm
No, it’s not arrogance. He just knows better than everyone else. Clearly.
vlghess - May 16, 2012 at 3:59 pm
Some of this discussion reminds me of Sheila Tobias’ “They’re Not Dumb, They’re Different” about retaining students in the natural sciences who leave for the social sciences or humanities more for “academic cultural” reasons than intellectual. Scientific writing, more than specialized writing in other disciplines, is often inaccessible to lay audiences because of unfamiliar technicalities that only fellow specialists can appreciate. It is possible to be accurate rather than sloppy–but there will always be a cultural gap between journalists (even those who write well about science) and scientists about the need to keep the reader’s interest vs. the need to avoid going beyond the facts…
MarjoryMunson - May 17, 2012 at 10:21 am
Of course you can – but it doesn’t happen nearly as often as it should.
prof_cj - May 18, 2012 at 9:45 am
Instead, it’s a blurb from Gladwell that says Lehrer “knows more about science than a lot of scientists.”
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This makes my brain hurt and that Gladwell seriously holds this up as a belief causes me to lose a lot of respect for Gladwell.