Friday, February 12, 2010

What is homosexuality good for?

Back to Jacques Balthazart’s interview about homosexuality and science (previous blog) with some comments on choice of words leading into some thoughts on evolutionary advantages of homosexuality.

An interesting point about the interview is how careful Balthazart is to avoid the word ‘abnormal’. Instead, he uses the term ‘atypical’ and he applies it generally to hormone levels in the womb, rather than to people or behaviour. On the one occasion when he does say ‘abnormal’, he immediately corrects himself back to ‘atypical’.

Choices of words matter to Balthazart. When the interviewer, even tentatively, talks of ‘abnormal’ or ‘anomalous’ people, Balthazart very quickly corrects him, pointing out that ‘abnormal’ may be fine as a statistician’s term but should be avoided here because of its pejorative (and normative) implications.

Despite this care, there are other choices of words that are not so apt: he characterises the hormone levels to which homosexuals are exposed as being ‘too high’ at certain points but ‘normal’ at others. (And le monde, reporting his work, chooses the equally partial term ‘disequilibrium’.) In our medicalised society, hormone levels that are too high, not normal, or in disequilibrium are targets for correction, and so this talk plays into the hands of people who want to regard homosexuality as a disorder to be treated (I’m sure that Britain’s former chief rabbi, Lord Jacobowitz, made precisely such a comment concerning medical intervention, but I haven’t been able to track it down). In the same way, psychiatric “treatments” for homosexual “disorder” have sprung from our psychiatrised society’s belief in the power of psychiatry to normalize any non-norm behaviour.

And right away we’re back to another “because” charade: “we cure because we care” say the bigots whose only concern is making sure everyone else is like them. The retort to which is obvious: “let’s seek medical and psychiatric interventions to cure the bigots of their bigotry”. Given that bigots far outnumber the targets of their bigotry, this would be a much more lucrative cure if ever we could find one.

But playing into the hands of bigots isn’t what really bothers me about this pussyfooting around the terms ‘normal’ and ‘abnormal’. It’s that if we’re concentrating on not giving the impression that homosexuality is abnormal (hence “bad”), there we’re never going to ask why it might be normal (hence “good”). In fact, I think it is not just legitimate but enlightening to ask what homosexuality—and, indeed, homophobia—is good for in the long path of human (and non-human) history.

The idea that homosexuality might be good for something first occurred to me while I was looking at a study of foxes (yes, I know I’m meant to be a linguist, but I have weirdly catholic reading habits). I can’t recall the exact details now, but at some point, for whatever reason, the fox cubs were abandoned. However, rather than being left to starve, their uncle turned up and fed them. This put the idea into my head that it may be disadvantageous for the parents (from an evolutionary/genetic point of view) if the children come into conflict over resources when trying to raise the grandchildren, meaning that the grandchildren each have less access to resources. Conversely, it might be advantageous for the parents if one of their children cooperates in the raising of the grandchildren, providing them with greater access to resources. Clearly, homosexuality is a simple way of ensuring this, especially if homosexuals form valued parts of extended family units (contrary to the “family values” propaganda).

Support for this idea comes studies examining where in age range of the family homosexual offspring are more likely to occur. One paper, reporting four separate studies, found that ‘the number of biological older brothers, including those not reared with the participant (but not the number of nonbiological older brothers), increases the probability of homosexuality in men’ (pnas)—the paper is particularly interesting because, as the middle part of the quotation shows, it controls for a number of nonbiological, environmental factors. A different paper, dealing with a smaller sample, found that male homosexuals have ‘have a greater number of older brothers, older sisters and younger brothers’ (royal society). In all the studies, there’s a correlation between family size and (male) homosexuality. If homosexuality is a means of providing more resources gatherers for, and fewer resource conflicts between, grandchildren, then these are precisely the types of results one would expect: once one has produced enough reproducer males, one’s interests are better served by producing resource sharers (as non-parental adults would be) rather than resource dominators (as parental adults would be forced to be).

I think that marital practices around the world support this way of looking at the benefits of homosexuality. Consider fraternal polyandry, where two brothers marry the same wife and therefore end up raising children who are either their children or their nephews/nieces. Apparently, this practice has developed in regions of Tibet where resources are very scarce. The fact that it’s connected with resource management is important. It prevents conflict over resources between siblings raising different sets of children and instead provides a greater number of resource gatherers for the same set of children. This is the same effect as would be achieved by having a homosexual uncle who plays a semi-parental role to his brother’s offspring. In other words, where biology isn’t enough to guarantee it, cultures can develop a form of marital behaviour that mimics the benefits of homosexuality.

I wonder whether consideration of resource management and marital patterns might also shed light on homophobia. Underlying the idea of the advantages of having some homosexual offspring is an assumed scarcity of resources requiring management. Of course, part of the evolutionary success of humans results from our having altered our environment, especially by making it much more resource-rich through agriculture and herding. In the face of an abundance of resources, biological interests might be best served by having all one’s offspring producing more sets of offspring, rather than collaborating on raising fewer. This would lead to pressure against homosexuality.

Again, cultural behaviour provides support for this view. Specifically, consider studies correlating the loss of matriarchal social structure with the introduction of cattle: matriarchies are good at preserving small landholdings intact, but once the economic mainstay of a group shifts to cattle herds, which, unlike landholdings, reproduce and so are divisible, the structure of the group shifts to a patriarchy (ecology and evolution). A strongly patriarchal culture is likely to stigmatise male homosexuality because it looks like a dereliction of duty or a form of subversion: abandoning the man’s dominant role and adopting, or desiring another man to adopt, one similar to the subordinate female one. If this is right, then it suggests a link between cultural homophobia and expansionist reactions to resource abundance.

So, bearing in mind that our cultural aversion to homosexuality stems from the patriarchal customs of a nomadic people, descended from herders, concerned with the conquest of new resources and a speedy increase in population, is it then any surprise that they should have stigmatised homosexuality?

I argued in my earlier posting (link) on this topic that facts about what natural don’t entail much about what’s right. And if homosexuality and homophobia both have their own natural histories, then neither has the upper hand in the naturalness stakes. However, if we ask which aspect of our nature is better adapted to the challenges facing our current societies it’s pretty obvious that expansion-driven resource domination is far inferior to resource sharing for the benefit of the next generation. Let the family “values” lobby mull that over for a while...


  1. Roughgarden has advanced this argument about the adaptiveness of sexual orientation and gender diversity in her 2005 book and in a 2006 Science paper. Haven't read either, but I remember listening to a radio program about the book. I wonder whether the supportive gay uncle theory makes equal sense for lesbian aunts, however, given the asymmetries in number of potential offspring and in resource exploitation.

    Arguing that homophobia is also 'adaptive' in the relevant sense is an interesting possibility although I'm not convinced it's actually a biologically determined, inheritable trait. It's far too easy to 'cure'.

  2. Hi Linnaea, thanks for the lit tips. I'll follow up. It'd be great to see the ideas sketched above worked out properly: I see from the abstract that Roughgarden uses game-theoretic formalism, which is how this should be approached, I think.

    Re the other two points you raised:

    1. Yes, the scenario I was sketching could easily lead to gender disparities in homosexuality. The PNAS article (see blog) suggests that such disparities exist. If the quantitative data is sure enough, these disparities might present an interest test scenario for a formalised game-theoretic approach such as Roughgarden's.

    2. The sense in which I was thinking homophobia might be adaptive was not a biological evolutionary, but a cultural evolutionary one: given certain resource scenarios (as in a society with not immediately finite resources which is, in consequence, capable of rapid, sustained expansion), a homophobic group might come to dominate more resources than a non-homophobic one. If so, you'd be right that homophobia is neither biologically determined, nor heritable, and so eminently curable.