Tuesday, October 27, 2009

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?


Fixed Carbon said...

Should you not justify your assertion that the causes present global warming is "underdetermined"? What is the evidence in this case, and what would you accept as evidence for "determined"?

Anne Buchanan said...

Sorry, not to be clear about this. To you or to me, the causes of global warming may be determined, but our point is that different people can interpret the same body of evidence in different ways. This is as true with global warming as it is with evolution. Most Americans disavow both, in spite of piles of evidence. Why?

Ken Weiss said...

I am a former meteorologist, but not a geologist nor climatologist, so can't claim to be an expert in the details. I also have no _personal_ doubts that (a) climate is in a warming period globally, (b) what humans do is chemically related to greenhouse and other effects that should lead to climate change, and (c) it is convincing enough that human activities are responsible that urgent remedial action is justified -- the safer bet even if there were some doubts.

But underdetermined areas are those in which the information is incomplete enough that alternative explanations, either existing or imaginable, might equally well account for the data. So two points on an x-y plot of, say time vs some value, can always be fitted by a straight line, but that doesn't imply that they can't also be fitted by a curved line. If you have 4 variables but only 3 data points, you can fit many different 'theories'.

In that sense, some legitimate scientists (not just flat-earthers) question how rigorously or how much we can attribute observed climate change data to the anthropogenic theory (since, for example, geologically climate has warmed and chilled countless times over the past many billions of years).

Ours is not a denier's statement about climate change! As usual in our blog, we try to step back and observe more neutrally, and often comment on the degree and nature of commitment to a particular theory, or 'tribalism' as we refer to it, that is so common in science as well as other areas.

There are many factors that affect any indivdiual's commitment to a particular worldview. Data themselves are not the whole story.

Arjun said...

I like how you frame "Are we tribal for genetic reasons, or is it cultural?" as a meta-question in regard to the examples of points of scientific contention preceding it.

However, the question implies that the hypothetical causes are mutually exclusive.

Although we are apt to consider two theories that describe a single phenomenon 'in competition' with one another, I can think of at least one case in which two theories describing the same phenomenon persist and in which they are seen to complement each other: the Valence Bond Theory (VBT) and the Molecular Orbital Theory (MOT) for describing how atoms bond to form molecules.

In short, VBT states that given 2 atoms participating in a chemical bond, each atom donates one electron, and the resulting pair tends to stay in the vicinity of the bond.

MOT describes the electrons of bonded atoms as more or less 'spread out' across the molecule.

While both models share the same predictive power, VBT requires messier math, thus restricting its application to smaller molecules as compared to MOT. However, we can draw on concepts from VBT to give us a better idea of cerain aspects of chemical bonding, reactivity and structure (don't want to drown in detail here).

Although we use both VBT and MOT to model bonding, it doesn't seem that they have been subsumed under an over-arching theory and hence they retain their epistemic autonomy while complementing each other.

Regardless of this example I ask "Why should we care about underdetermination?" I suppose it provides a means of triage, an idea as to which garden path we should follow.

But if one school of thought better describes a phenomenon than another and vice versa, why not allow both to develop, to each scale their own peaks and improve their respective vantages?

Arjun said...

This problem seems to arise most conspicuously when we try to APPLY what we know, whether it be in the political or technological arena.

Can't we just let academia tinker away at its curios?

Ken Weiss said...

Academics have the luxury of tinkering, but many don't. Also, money is distributed for research and application based, essentially, on advocacy resting in part on the interpretation of data. Vested interests arise from that.

In some things, perhaps like the wave/particle duality, we know we are using the version of the presumed unitary truth that suits our needs. We don't claim that light is just a wave phenomenon.

Different kinds of evidence can be brought to bear to defend various points of view. The real problem arises when there truly are multiple (often infintely many) theories that may fit the data.

Evolution is one such area, often. Different relative contributions of population size, multiple functions, natural selection, organismal selection, etc. may give comparable fit to limited data. Those who see selection under every bed will create selective Just-So stories. Those who think life is more complex and chancy will construct drift-centered explanations.

So long as we acknowledge the level of speculation, things are OK, and perhaps will lead to further investigation to find out more, rather than just to support one's own view.

Anne Buchanan said...

Arjun, as you suggest, much of this can just be left to academic tinkering/tinkerers, but to me there are interesting epistemological and sociological questions, too. E.g., how do we determine cause and effect? How do we decide when a theory is 'done'? Why do people choose one competing theory over another? So much of how a theory gains heft and a following is beyond what we all learn about how to do science, and the scientific method, and yet an integral part of science, too.

Fixed Carbon said...

Dear Ken Weiss: What do you think about the testimony in the Senate re GW. You can read it at the WAPO. Oct. 28. Google, "A Senator in a Hostile Climate," by Dana Milbank.

Ken Weiss said...

I happen, personally, to be convinced that global climate is really changing and that a lot of it is anthropogenic. I want us to do something to stem the changes. But why? I don't look at the evidence with a professionally skilled eye. Do you? If so, then your view may be more solidly grounded than mine. Otherwise, we're accepting the word of people whose word we choose to respect. Often that fits our personal preferences.

People testifying before Congress, journalists, and even scientific papers are colored to favor their authors' views. 'Colored' does not mean falsified, but we all come to the table with our own agendas, and usually with preconceptions as well.

There are articles, even by respected non-flat-earth geoclimatologists that question the nature or at least the magnitude of effects, their source, and the degree to which they are part of natural geo-episodes or are anthropogenic. The net conclusion one comes to has a subjective element as to how each part of evidence is weighed.

There are even, of course, those (mainly Republicans and Libertarians?) who say quite truthfully that the earth will survive whatever we do to it. Let's eat, drink, and be merry and cash in our stock coupons while we can. What the hell--we may not survive, and New York or the Maldives may not survive (I'd rue the Maldives, but New York? It depends on who wins the World Series). But as a species we'll adjust, our economies will adjust, and even humans will manage. Yes, there may be wars, starvation, dislocation, and even pestilence. But they have always been with us.

Or,even if it's curtains for Homo sapiens, it's part of evolution and is natural. Many other species will say it's about time we had our commupance.

I'm not of that ilk, but it is a lgegitimate way to assess the nature of the evidence and what to do about it. I find that view selfish and objectionable, and perhaps you do, too. But that doesn't make us right no matter how convinced we are that we are right.

Anyway, if you don't agree in this instance, there are many other examples of things in science that everybody knew to be true, but that were later shown not to be. And many times that is because theories are underdetermined.