Thursday 11 April 2013

Balham Barnets (again), Darkness in El Dorado and the value of the scientific method

I said yesterday that I would try and write about what had prompted that day's blog; well here it is.

There is, I think, a great deal of difference between what I 'publish' here on this little blog, whether the author is the Penguin or whether it is MG, and either published non-fiction (in book form) or journalism. ( I exclude publications such as the 'National Enquirer' or the 'Sunday Sport' from my definition of journalism for what I hope are obvious reasons.)  This blog is simply the ravings of an unbalanced mind and while some of it may be deadly serious, I do not expect any more credence to be given to it than one might give to a drunk propping up the bar at 10:30pm in one's local hostelry. I do not earn a living from it, I am scarcely committed to most of the ideas presented and time precludes any more than the most cursory research and fact checking.

On the other hand journalists are expected, the public do have this expectation, to check facts, make reasoned arguments and clearly display the measure of objectivity or subjectivity contained in the piece. The same strictures apply to the writing of non-fiction; too little objectivity turns the work into faction or out-and-out fiction.

In 2000, Patrick Tierney published a book entitled 'Darkness in El Dorado' which not only probably ruined two academic careers and reputations but cast doubt on the motives and methods of the academic anthropology community in the USA. Essentially the readership of the book was being led to imply that the actions of an anthropologist, Napoleon Chagnon and an accompanying geneticist, James Neel, had 'caused' a measles epidemic among the Yanomami people of Venezuela and Northern Brazil for somewhat dubious purposes. The Yanomami people are some of the most studied group of indigenous people in the Americas and elsewhere  and were often held to be a good representation of a so-called 'primitive culture' living in isolation.

In 1967 Neel and Chagnon planned a field trip for 1968 to Venezuela and Brazil which sought, among other things, to determine possible reasons for the increase in lethality of 'common' diseases amongst 'westerners' when these were 'introduced by infected individuals who lived outside the normal range of the indigenous populations. The story of the colonisation of the Americas by first the Spaniards and Portuguese and later by the English is littered with tales of the decimation of local populations by disease which the indigenous people had no resistance to whatsoever.

In October 1968, when Neel and Chagnon had arrived in South America, armed with a vaccine for measles, which disease, if left untreated and with little or no immunity killed more than twice as many people as the disease caused among those unvaccinated 'westerners', a measles epidemic had arisen among the the Yanomami people. In keeping with the old adage that there is no smoke without fire, Tierney, along with many others prompted by Tierney's book, effectively laid the blame on Neel and Chagnon's administration of the vaccine, which like all 'live' vaccines can cause the symptoms of the disease being vaccinated against.

Neel had also been using a older version of the vaccine, which was still in use in the USA but usage was declining due to the development of more attenuated, less virulent, vaccines which offered a better chance of not developing symptoms. Whether cost was a factor in the choice, the newer version were perhaps more expensive, I have been unable to determine. Tierney effectively tarred the two researchers with the brush of dubious ulterior motives because of that 'supposed' smoking gun of the vaccine.

One of the many lessons taught to us by the scientific method is to weigh all of the evidence before making a judgement, not just the evidence which supports your hypothesis. The classic example is a double blind trial (no-one knows who got what until the results are tabulated) where a placebo is involved. A new drug has a 'cure rate' of 25% in the patients treated with that drug, with 3% of patients experiencing adverse side effects. This is better than the 15% success rate of an older, competing drug, with higher adverse effects, therefore you should use the new drug. This is quite obvious, would you not agree? On that evidence, it is a no-brainer. However, we introduced a placebo into the trial and that has a success rate of 25% with zero side effects. Now which one do you use? It is not quite so simple now, is it?

What Tierney did not take into account because it did not accord with what he believed, was that the outbreak must have started prior to Neel's and Chagnon;s arrival because of the relatively long period between infection and manifest symptoms, between 7 and 18 days; the likelihood that Neel was vaccinating individuals after 3-4 days post infection, at which point the vaccine is largely ineffectual and the fact that the progress of the epidemic was in the opposite direction to Neel's progress through the country. While the vaccine may have contributed to the extent of the epidemic in producing symptoms as a result of the vaccine, which rarely if ever kills, it is impossible to determine the extent of such an effect since the inhabitants were not necessarily free from infection when they were vaccinated. There was also an implied cross infection by vaccinated subjects which is unheard of in the literature; you cannot pass the infection caused by the attenuated 'live' virus by normal means to another human being.

Wiki lists the claims made by Tierney in his book as:
  • That Napoleon Chagnon and James Neel directly and indirectly caused a genocide in the region through the introduction of a live virus measles vaccine.
  • That the whole Yanomami project was an outgrowth and continuation of the Atomic Energy Commission's secret program of experiments on human subjects.
  • That Chagnon's account of the Yanomami are based on false, non-existent or misinterpreted data, and that Chagnon actually incited violence among them.*
  • That French researcher Jacques Lizot, protégé of anthropology icon Claude Levi-Strauss engaged in sex acts with Yanomami boys (including oral and anal sex, as well as having the boys masturbate him).
  • That a researcher married a Yanomami girl who was barely entering her teens.**
It is difficult not to see the words 'grind', 'to' and 'axe', not necessarily in that order, nestled in there somewhere; sometimes I think it is a pity that human being are so susceptible to conspiracy theories.

* Highly improbable. Chagnon may have overstated the case but many researchers attest to the normal, for human beings, willingness to engage in violence to secure finite resources, both food and women. In this, he may have been influenced by a common sentiment; that indigenous peoples lived in some kind of 'natural grace', 'the noble savage', at one with their environment. Goodall experienced much the same reaction when she punctured the myth of the peace-loving chimpanzee.
** Aside of the ill-wisdom of getting that involved with the subjects of your research, this was a normal age for Yanomami women to be married.

Postscript:

A little photograph of proud Lisa's new addition to 'la famille Booker'; aah, ain't she cute!


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