Wednesday, December 28, 2011

Mars and Venus: thoughts on the nature and evolution of (sssh!) sex. Part II

We tried to make a delicate point in the wake of the Penn State child abuse scandal, which seems to have  'released' inhibitions across the country, perhaps even more readily than a decade or more of stories about abuse in the Catholic Church.  If up to a quarter of people were abused as children, and even if each abuser was a multiple offender, then abusers are very common in our society.

In the previous post in this series we reviewed an article by Barron et al., in the December 2011 BioEssays, that argued that we now clearly know that there is much more variation in sex-related behavior than a dichotomous male-female view reflects, and that a more nuanced, variation-reflecting truth should be taught in college courses.  Plus, of course, if there is so much variation and if it is biologically based, that may call for explanations about how it could have evolved, given the strong and direct fitness effects associated with reproductive success.

If gender behavior evolved because of Darwinian selection for successful reproduction, a long-standing problem for evolutionary biologists has been to explain the much less common aspects of behavior such as homosexuality, trans-sexuality, voluntary celibacy and the like.  Rationales and (we would suggest) post-hoc wriggling have been offered to ensure that gender behavior is indeed biologically driven by a long history of selection 'for' successful reproductive strategies.

Of course, if there is variation in genes that causes these kinds of anomalies (assuming that they can be called that), one can ask why they exist.  The variants must be new enough not yet to have been screened away by selection....yet homosexuality is far too common to have survived such stringent selection.

Culture can make people do strange things, like be suicide bombers, commit infanticide, or agree to voluntary celibacy.  In this sense, culture is a human trait based on imagined truths (going to Heaven for such acts, for example).  That means culture can override biological 'imperatives' a view that we would personally agree with.  But there's more, since the term imperative invokes just the kind of dichotomous thinking that Barron et al. object to.

So among other aspects of variation in sex and gender behavior, what could possibly explain anything resembling a quarter of people being sexually abused and so many abusers?   We know that some cultures allow or even mandate consummated marriages for children of ages that in our society would be defined as sexual abuse.  This includes cultures that in various ways allow or mandate homosexual encounters with what we define as 'children' (classical Greece is one example, but only one).  Definitions of what constitutes rape vary over time, and one can easily list variation that clearly muddies up any simplistic evolutionary arguments:  stoning adulterers in societies that now, or recently, have allowed or encouraged polygamy; making forcible sex in marriage illegal and calling it rape; same-sex marriages, and more.  And of course there were laws about inter-racial sex or marriage, and there is the current abortion controversy.

Society can determine what is accepted behavior and who can be locked up for what.  Is our idea that child abusers are pathological purely cultural and definitional? Or, why are there so many of them?  After all, especially in the case of same-sex abusers, what evolutionary mandate is being reflected in their behavior?  Are they super-sexed-up so that during their lives they actually sire more children than their contemporaries--in which case their 'abuse' is simply a manifestation of their superior sexuality?  But this seems unlikely since most people are not sexually attracted to children.

Since our society calls child sexual abuse abnormal and illegal, and in our society, the effect on children can be profound and lifelong, people certainly should not do it!  But it seems too common to be called 'abnormal' in the medical or psychopathological sense.  The article by Barron et al., if even reasonably on the mark, implies that as a population we have not come to grips with the natural variation in sex-related behavior.  Whether the variation is caused by genes (and if even that means it is 'mandated') or by culture, its very existence raises questions that evolutionary psychology should take seriously rather than ignore or sweep under the rug (much less be oblivious to).

Should how and where social policy and legal constraints ought to be applied be derived from a better understanding of biology, or is it appropriate for cultural and religious criteria to be used to establish constraints, whether or not they go against biological 'mandates' (if there are such things)?

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