Someone named Dan Slater recently wrote a book, Love in the Time of Algorithms, and has an op-ed out titled Darwin Was Wrong About Dating. The piece is littered with generally unpersuasive refutations of the relevance of a Darwinian framework in understanding the evolutionary origins of human behavior. I say this while granting that I have come to find much evolutionary theorizing somewhat shoddy. But that’s true for much of science, and scholarship more generally. It just so happens that evolutionary psychology has social and political relevance, while other fields do not. Wrong science does not negate the importance of an evolutionary framework.
There has been some discussion in the comments why the posts on inbreeding are getting so much attention. I think this is a milder form of the same sort of curiosity about why young males have a fascination with pornography: we are obsessed with sex. This is not an arbitrary fascination, nor is it a loss of innocence which may have been avoided. Sex is our raison d’etre as sexual organisms. Evolutionary psychology gets a bad reputation for positing adaptive explanations for everything under the sun, from dancing to migraines. But, if there is anything which is the target of adaptive constraint and selective pressures, it is the suite of traits which relate to sex and mating in a direction fashion. It is sometimes stated that sex is about power, but the bigger reality is that power is about sex.
But reducing human behavior purely to one explanatory framework is too reductive even for me. An individualist framework where singular males and females operate as evolutionary versions of rational H. economicus, always optimizing fitness through subterfuge and inducement, leaves something to be desired in characterizing the true rich tapestry of human behavior. And this tapestry is not arbitrary; rather, its general shape and topography is anchored by particular innate parameters.
A reader reminded me of an amusing paper, Who Likes Evolution? Dissociation Of Human Evolution Versus Evolutionary Psychology. The gist of the results are below (I added some clarification):
John Horgan has a long review of Robert Trivers’ long overdue book, The Folly of Fools: The Logic of Deceit and Self-Deception in Human Life. I really don’t care how well Trivers analyzed the topic, this is such a rich and important issue that I can’t help but think he must have hit some important mines of insight. I haven’t read The Folly of Fools, but I can recommend Natural Selection and Social Theory: Selected Papers of Robert Trivers. It’s not just a compilation of papers, there are biographical chapters which flesh out the context behind a particular idea at a given time. Trivers also shows up prominently in Defenders of the Truth: The Sociobiology Debate and Mother Nature: Maternal Instincts and How They Shape the Human Species.
A new paper in PLoS Biology is rather like the last person to leave turning the light off. Evolutionary psychology as we understood it in the 1980s and 1990s is over. Darwin in Mind: New Opportunities for Evolutionary Psychology:
None of the aforementioned scientific developments render evolutionary psychology unfeasible; they merely require that EP should change its daily practice. The key concepts of EP have led to a series of widely held assumptions (e.g., that human behaviour is unlikely to be adaptive in modern environments, that cognition is domain-specific, that there is a universal human nature), which with the benefit of hindsight we now know to be questionable. A modern EP would embrace a broader, more open, and multi-disciplinary theoretical framework, drawing on, rather than being isolated from, the full repertoire of knowledge and tools available in adjacent disciplines. Such a field would embrace the challenge of exploring empirically, for instance, to what extent human cognition is domain-general or domain specific, under what circumstances human behaviour is adaptive, how best to explain variation in human behaviour and cognition. The evidence from adjacent disciplines suggests that, if EP can reconsider its basic tenets, it will flourish as a scientific discipline.
But now that the once popular “single-origin model” of the evolution of Homo sapiens has been disproved, and the previously controversial “multiregional hypothesis” has been proven by DNA evidence, perhaps we need a rethink. According to the multiregional hypothesis all modern people, including modern Africans, are the descendents of breeding and hybridising between separate ancestral groups, all at various stages of evolutionary development.
Evolutionary lice research has helped palaeoanthropologists, including Stringer, to embrace the multi-regional hypothesis. “I’m sure there is plenty more to come from the lice research,” he told me. We know that it took 4m years, 5-9m years ago, for our ancestors to completely split from archaic chimps. During that time hybrids would have been born that mated both with our ancestors and ancestral chimps.
In the wake of yesterday’s review of a paper on heritable variance in trait preferences realized in romantic partners I couldn’t help but be intrigued by this new study out of PLoS ONE, Evolutionary History of Hunter-Gatherer Marriage Practices. It’s actually a pretty thin piece of work in all honesty from what I can tell. They wanted to query ancestral ranges of marriage patterns by mapping the cultural variation in customs onto a phylogenetic tree. To generate that tree they took mtDNA sequences, which to me seems kind of old school. Using the cultural patterns present in living hunter-gatherer groups they presumed they could infer the ancestral state.
So combining these two sources of data they generated this:
Judging by some of the amusing search queries I find every Friday people have a wide range of tastes and fetishes when it comes to pornography. From what I can tell the realized phenotypic interval in mate choice is less varied and eye-opening, but exists nonetheless. Why? Is there a rhyme or reason, or is it simply random chance and the necessity of the biological clock ticking? These are not issues which aren’t discussed or mooted thoroughly regularly. The popular science literature is littered with hypotheses from social and evolutionary psychology. How else could you have a books such as The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature and Survival of the Prettiest: The Science of Beauty. This is sexy science by definition. Not Physics Letters.
There are three broad issues which have interested me in the domain of attraction and evolution. First, what is the character of cultural universals of beauty rooted in biological preferences? Second, what is the character of cultural variation in beauty rooted in contingencies or local conditions? And third, what are the genetic and non-genetic factors in individual mate preference? In this post I’ll focus on the last. Not to put a fine point on it: are you born with a “type,” or is your “type” a matter of chance and necessity after you are born? An interesting twist on the second issue is that one phenomenon which falls into the “not born” but biological category is the process of sexual imprinting. For example, you may exhibit attraction to individuals who resemble your opposite sex parent.* The clear connection to the presumed “Oedipus complex” of this probably explains it prominence.
A new paper in The American Naturalist aims to examine the question of realized variation individual preferences with a huge sample of twins, monozygotic and dizygotic. By realized, I mean that they focus on the people with whom you actually pair up, not your ideal avowed preference. Variation in human mate choice: simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating:
Today in Slate there’s an argument for why society should discourage first-degree incest. The main thrust of the piece seems to be broadly utilitarian, in that incest is destructive to the family unit and society has a rational motive in discouraging the practice. The reason that the argument is even made is because of analogies that some social conservatives make between incest and gay marriage. I’m not too interested in the argument against first-degree incest, because I think this is a practice which is aberrant because there are biological dispositions most humans have which make it unthinkable.* Though the genetic reasons are broadly well known, Steven Pinker reports on the psychological mechanisms which enforce the taboos in The Blank Slate.
Of course there are exceptions to the rule. The first-degree incest taboos can be violated in the case of royal families which wish to preserve and accentuate their divine genealogical essence. This was famously well known in ancient Egypt down to the Roman conquest, but one also found the practice in Hawaii. In rural Egypt apparently brother-sister marriage continued among commoners (who presumably emulated the elites) down to the Roman period. Human nature has dispositions in many cases which are not “hard-wired.” But the disposition in this case is so strong that I believe arguing about the legality of consensual adult incest is an academic matter. The discussion is only surfacing because of its possible relevance to another issue, gay marriage.
Polygamy though is a different case. Here the ethnography seems to be clear that though the majority of men in the majority of societies did not practice polygamy, in most cultures polygamy was acceptable, and commonly practiced by high status males. In many cases polygamy was the preferred ideal, which was not attainable for the typical male due to economic constraints. Only with the spread of Western-normative mongamous customs, inherited from the Greeks and Romans, has polygamy been marginalized.
But we may be better for it. Polygamy’s many wives don’t capture ‘market value’: