The recreational habits of (life) scientists

[This post has been lurking about since, oops, May, so I thought I better put it out there!]

I’m sure everyone has favourite inductive hypotheses about the world that they mull over as potential research questions–if only they weren’t so utterly trivial. Besides, I usually only notice the confirmatory evidence for mine.

The co-incidence of a single case supporting both my pet hypotheses about the recreational habits of scientists came to my notice today: a life scientist who was both a musician and a rock-climber*.

Climbing blue musicians

Previous conversations with colleagues have usually revealed that most biologists (broadly construed) think there seem to be more-than-average numbers of musicians in science. The science/music overlap is one of my pet hobbies, and many popular accounts touch on this relationship as possibly having something to do with a certain kind of brain processing. Okay, whatever, personally I think the causation factor is an objectively defined measure of “cool” or “awesome”. But there’s no statistical evidence–least not that I can find–that musicians are overrepresented in the subset of humans who call themselves scientists, compared to, say, landscape gardeners or art historians. Controlling for age and socioeconomics and all that demographic stuff.

My other inductive hypothesis is that life scientists, especially those working in cultural evolution, seem to be rock-climbers more often than chance might predict. This might be a case of cultural transmission though, because rock-climbing is something that you generally have to be introduced to in a social context, seeing as how it is useful to have someone on the other end of the rope.

Data enabling proper testing of these hypotheses would require more effort than random conversations at the pub, so for the moment, the assertions go unverified.

* And who wasn’t me. Although I haven’t been climbing for so long I doubt I still qualify.

[Photo from mr_o‘s flickrstream]

Darwin married his cousin: a lesson on cultural diversity

From Sunday’s Observer, Split over health risk to cousins who marry:

A major medical row will erupt this month when scientists and health experts hold two key meetings to discuss the controversial subject of marriages between cousins and their impact on health in Britain.

Really? I love the clairvoyance afforded to newspaper journalists. They obviously also considered that by Monday morning this article hadn’t made waves enough, as the title has been changed to “Row over health risk”.

Some researchers and politicians say inter-cousin unions, which are highly prevalent among British Pakistanis, have led to a striking rise in the incidence of rare recessive disorders, many of them fatal, in areas such as Bradford. The trend has led to calls for cousin marriages to be banned.

The reasonable science in this piece, as usual, follows after the experiential, moral-panic-related anecdote from an MP, who, despite any obvious medical qualifications, says that:

‘I also know of several sets of parents in my constituency who are cousins and whose children are severely disabled. I have no doubt that the mothers and fathers being closely related to each is a key factor.’

“Striking rise”. “No doubt”. And my favourite:

“you have a child with your cousin, the likelihood is there will be a genetic problem”.

That last from an environment MP, who is presumably drawing this conclusion from an episode of the X-Files.

The voice of reason comes from Aamra Darr, who has written sensibly on the topic of cousin marriage amongst British Pakistanis before. She points out that cousin marriage is one of many diverse
marriage patterns adopted by people for a variety of reasons, but more importantly, the risks of genetic problems with offspring are identifiable and manageable. Genetic knowledge is useful.

The unilateral prescription of social norms by one group in a multicultural society, based on thin-edge emotional judgments and ignorance about cultural diversity – this is not useful. It is also just dumb. Around the world, marriage to cousins is more often permitted (or preferred!) than it is not. Here are some data.

The blue section (not even a third) contains those societies in which marriage to first or second cousins is NOT permitted. The other two allow some form of marriage to cousins, with the red slice indicating the percentage who allow first cousin marriages. These figures are from the Ethnographic Atlas, which contains information about 1267 ethnographically described societies. Some 243 societies had missing data for this category, but ~1000 is a good sample of the world’s cultural diversity.

An argument for––or against––cousin marriage does not gain any moral weight from these numbers. The existence of such cultural diversity, however, begs the question to those who are opposing cousin marriage on genetic grounds: where is your evidence for large-scale, worldwide problems with recessive heritable disorders arising from cousin marriages? Though there are no direct data, one might argue that if at least a third of human societies can maintain such a marriage preference, it implies that any genetic problems are not so severe as to be cumulatively damaging for all individuals. And that is another point: just because a social group permits cousin marriage, it does not follow that every individual in the group marries their cousin. Population thinking seems to be very hard for many people to grasp.

It appears to me that there is not much science going on with any “call” for banning cousin marriage, but something more like prejudicial gut-reactions combined with availability heuristics. That’s just speculation, however.

But I’m still confused about that major medical row. What was the point there?

With thanks to Aamra Darr for a clarification.