Is tribalism genetic?

Philosophers have a word for the situation in which the available data aren't sufficient to allow a decision between competing theories. That is, when two or more theories fit the data equally well (or equally poorly). They call this underdetermination, and it can be applied to many situations. Many theories of causation in epidemiology are underdetermined, for example -- numerous studies support the view that asthma or multiple sclerosis or heart disease have a genetic cause, but there are also numerous studies showing that these diseases have an infectious origin. Global warming is another example -- is it man made or just natural cycling?

Anthropology seems to be the intellectual home of many theories of uncertain interpretation. Perhaps this is because human behavior and evolution are notoriously difficult to assign 'true' causation to. Are humans innately violent? Are the behavioral differences between men and women culturally determined? Why, if evolutionarily the important things in life are survival and passing on our own genes, do people commit infanticide, or blow themselves up in suicide bombings?

Some theories are not underdetermined, they are just plain wrong, but that doesn't stop them from having believers, even believers who claim that scientific evidence supports the theory. ID adherents, of course, would claim that much of the same data that evolutionary theorists use to support the common origin of all life on Earth instead point to a divine origin.

Anthropology can claim many unsupported theories, such as that humans are genetically programmed to fear snakes, or that West Africans are fast runners because they were cattle thieves millennia ago, and had to be able to run fast to escape with their quarry, but most of these are better placed in the category of evolutionary Just-So stories, rather than underdetermined theories. They might be true, but how would we ever know? Can we rule out all other reasonably plausible explanations? Given the vagaries and weird one-off happenings over large areas and vast numbers of generations, how can we rule out something we haven't thought of?

Some questionable theories can claim actual scientific evidence in their support, including the aquatic ape hypothesis that Holly wrote about last week. A number of such theories continue to have legs in the Anthropology realm, even with overwhelming evidence against them. One is the idea that the closest living relative to humans is the orangutan. This is a not only a minority view, but the molecular and morphological evidence in favor of the 'alternative' hypothesis, that chimps are our nearest relative, is overwhelming and has been for decades. Jon Stewart gave this theory probably as much credibility as it deserves on The Daily Show back in August. Mark Stoneking has a commentary on the orang hypothesis in this month's BioEssays, in which he nicely refutes the 'evidence' as published in a recent paper in The New Scientist. He concludes by saying:

Finally, what are we to make of the fact that a paper whose arguments about the relative value of molecular genetic versus morphological evidence for phylogenetic analyses can be so readily dismissed gets published in a peer-reviewed, scientific journal? An accompanying editorial offers the illuminating insight that the paper "... comments on a topic of such keen general interest and therefore may well gain wide attention in the scientific and popular press." That it did, as the journal's website proudly points to coverage of the paper in The New Scientist. The editors also admit that although the reviewers were not convinced by the paper, nevertheless it "...was felt to be a contribution worth putting out to the test of further scientific scrutiny," even "though "...this perspective might superficially appear to be nonsensical to the majority of molecular anthropologists and systematists..." Yes, sometimes the conventional wisdom is overturned, and alternative views do deserve to be heard - but if publication in a peer-reviewed journal is to have any meaning at all, editors and reviewers have a responsibility to ensure that well-established contributory evidence is not dismissed in a superficial way.

A second Anthropological controversy that won't die has to do with interpreting the fossil remains of hominins found not long ago on the Indonesian island of Flores. Named Homo floresiensis, the majority view is that these remains are of hominins who lived some 18,000 years ago, they were small, and various features identified them to the discoverers as hominins, but perhaps belonging to a separate species that evolved on Flores. Others have argued that the remains don't deserve species status, but instead represent humans who happened to have been microcephalic--that's a harmful disorder, not just a description. Among other reasons to doubt this interpretation, however, are the results of a comparison of these remains with skulls from modern individuals known to have been microcephalic. The fossils do not look diseased to these researchers, but indeed, this 'controversy' is starting to spawn other unlikely disease possibilities. At this point, it is starting to look as though the dissenters simply refuse to be proven wrong.

Why do unlikely theories like these thrive? As Mark Stoneking points out, marketing interests can keep some hypotheses alive that should have died long ago. But, so can egos and career interests and so on. Often, which theory one chooses among competitors depends on one's prior beliefs, which can mean that some pieces of information are overlooked in favor of other data that seems more supportive of one's favored theory.

Everybody loves it when the circus comes to town. The clowns. The elephants. The stilt-walkers, and the side-show freaks. Kids of all ages snap up the tickets. Sometimes the 'circus' is the annual anthropology meetings, where a room is packed to the point of people (not monkeys) hanging off the rafters to see the food-fights. Another kind of circus, often, are the popular science magazines and television programs. They do, after all, have to sell ads the way circuses have to sell tickets.

Sometimes, we have no real idea of how to interpret data that would allow us to choose a theory -- we've got thousands of years worth of data on violence in human societies, but just how would we conclusively determine whether the cause is genetic or cultural? We clearly don't know, or we'd have sorted this out long ago. And sometimes we don't know how to ask the question in a way that would get us closer to an answer -- we may be better at understanding the causes of diseases like asthma or heart disease when we're better at understanding complexity.

While most theories in a field like Anthropology don't have much direct impact on how people live their lives, this doesn't prevent people from clinging ferociously to one interpretation or another.

Are we tribal for genetic reasons, or is it cultural?