Autism Vox

Science, Coincidence, and Mercury: What can you trust?

by Kristina Chew, PhD on June 1st, 2007

It has been asked: Why, in the face of evidence, do some still believe that autism is mercury poisoning?

In a May 18th Science article entitled Childhood Origins of Adult Resistance to Science, Yale University psychology professor Paul Bloom and Yale psychology graduate student Deena Skolnick Weisberg propose that resistance to certain scientific ideas (such neuroscience and evolutionary) originates in childhood “assumptions and biases” that continue on into adulthood. In particular, adults as well as children resist scientific explanations and information when these do not cohere with “common-sense intuitions about the physical and psychological domains”; also, adults as well as children are very much attuned to the “trustworthiness” of the source of the information.

Bloom and Skolnick open their essay by citing a 2005 Pew Trust poll in which it was found that “42% of respondents said that they believed that humans and other animals have existed in their present form since the beginning of time.” A “substantial minority” of Americans, that is, do not believe in evolution. As Bloom and Skolnick further write, “how children and adults process different sorts of information” is partially to account for resistance to science. On the one hand there is “common knowledge” such as beliefs in germs and electricity and children who “easily learn” the meaning of words (though I must point out that this is “not so common knowledge” for my son Charlie, who learns the meanings of words slowly and whose sense of germs and electricity exist not as concepts, but in the more concrete notions of something being “dirty” and of the “power” being on or not). In regard to knowledge that is not so commonly known and accepted, Bloom and Skolnick note that adults rely on the “trustworthiness of the source”—on the authority of a source—when deciding what to believe.

……in some domains, including much of science, direct evaluation is difficult or impossible. Few of us are qualified to assess claims about the merits of string theory, the role of mercury in the etiology of autism, or the existence of repressed memories. So rather than evaluating the asserted claim itself, we instead evaluate the claim’s source. If the source is deemed trustworthy, people will believe the claim, often without really understanding it. [my emphasis] As our colleague Frank Keil has discussed, this sort of division of cognitive labor is essential in any complex society, where any single individuals will lack the resources to evaluate all the claims that he or she hears.

This is the case for most scientific beliefs. Consider, for example, that most adults who claim to believe that natural selection can explain the evolution of species are confused about what natural selection actually is—when pressed, they often describe it as a Lamarckian process in which animals somehow give birth to offspring that are better adapted to their environments. Their belief in natural selection, then, is not rooted in an appreciation of the evidence and arguments. Rather, this scientifically credulous sub-population are deferring to the people who say that this is how evolution works. [my emphasis]They trust the scientists.

This deference to authority isn’t limited to science; the same process holds for certain religious, moral, and political beliefs as well. In an illustrative recent study, subjects were asked their opinion about a social welfare policy, which was described as being endorsed either by Democrats or by Republicans. Although the subjects sincerely believed that their responses were based on the objective merits of the policy, the major determinant of what they thought of the policy was in fact whether or not their favored political party was said to endorse it. More generally, many of the specific moral intuitions held by members of a society appear to be the consequence, not of personal moral contemplation, but of deference to the views of the community. [my emphasis]

Bloom’s and Skolnick’s thesis can be applied to one of the examples of resistance to science that they refer to, namely, “the role of mercury on the etiology of autism.” As Bloom and Skolnick note (and as they cite developmental data for), resistance to science arises in children when “intuitive expectations” clash with scientific claims, and this pattern of belief formation can persist among adults: “This resistance will persist through adulthood if the scientific claims are contested within a society, and will be especially strong if there is a non-scientific alternative that is rooted in common sense and championed by people who are taken as reliable and trustworthy.” It goes without saying that mercury (in the form of the mercury-based preservative thimerasol) as a cause for autism is, indeed, “contested within [our] society,” to the point that thimerasol will be on trial in hearings on 4,800 claims filed by parents of autistic children who believe that their child’s autism was caused by the U.S. government’s vaccine program (the hearings being on June 11th). While a connection between autism and vaccines might seem to make no sense, even to be a sort of “urban myth” to some, there are indeed some 4,800 plus families who think otherwise (this is one example). Again and again, one reads stories about how a child changed overnight from developing normally to becoming autistic, and some particular cause—some external agent—is sought to explain such a dramatic change.

One frequent source on a mercury-autism link has been journalist Dan Olmsted in his Age of Autism series, for which he has (as he notes in his most recent column today) written 100 articles over the course of two years. His May 30th column is entitled The Age of Autism: Quite the Coincidence; in it, Olmsted details a number of coincidences in the history of autism. Namely:

1. “The autism rate rises in tandem with increasing numbers of vaccines that contain a known neurotoxin, ethyl mercury.”
2. “Parents say their children became autistic after receiving mercury-containing vaccinations, sometimes several shots in one day.”
3. “Another remarkable fact that caught my attention: Autism was first identified in both the United States and Europe at almost exactly the same time. Child psychiatrist Leo Kanner published his landmark paper at Johns Hopkins University in Baltimore in 1943; pediatrician Hans Asperger published his — about a slightly less severely affected group of children — in Vienna in 1944. Cut off by a world war, neither knew of the other’s work.”

Olmsted writes that it is “amazing” that one comes upon so many coincidences when one reports on autism. But, to somewhat restate an oft-cited phrase regarding correlation and causation, coincidence does not equal causation either. Olmsted’s noting of the rise in the prevalence rate of autism—now 1 in 150 according to the CDC—turns one purported single cause for autism into the cause for autism through a rhetorical style of straightforward, commonsensical statements. Olmsted clearly notes that he is offering a “hypothesis” and is “speculative, yes” in saying that “some of the children exposed to this novel and neurotoxic form of mercury [=ethyl mercury] developed a novel neurological disorder called autism.” By deliberately understating the validity of his own claim, Olmsted buttresses it all the more via his constant use of what I will call the rhetoric of commonsense: How could one not believe what he write? How could one not see the connections—indeed the coincidences—that he points out, especially when the coincidences in his most recent column do just seem to accumulate so that a reader is persuaded to agree with Olmsted’s hypothesis, swayed by a rhetorical logic?

A further coincidence that Olmsted cites is that “the first three cases of autism diagnosed in the United States” can be “plausibly linked” to exposures of ethyl mercury via the occupations of the children’s fathers (the father of “Case 2″ was a plant pathologist, the father of “Case 1″ was a “forestry professor — not a very different occupation from plant pathologist,” and the family of “Case 3″ lived in a town called…… “lived in a town called Forest, Miss., near sites where ethyl mercury was first tested as a lumber preservative”). “Plants, forests, timber, the South,” writes Olmsted in a single-line (and rather poetic in its rhythm and evocation of images) paragraph. Olmsted has indeed identified a Washington, D.C., suburb, Beltsville, as the “ground zero” of autism; coincidence alike informs his line of argument in The Age of Autism: Ground Zero:

Recently, a mutual friend in Washington introduced me to a 58-year-old man with Asperger’s disorder, the milder version of autism. We got together for lunch, and when I asked where in the Washington area he lived, I was both startled and somehow not surprised: Riverdale, Md. That’s another Washington suburb that clusters with the College Park-Beltsville-Greenbelt dots I was already plotting. What’s more, he was born there in 1948 in the same house he lives in now.

I asked what his father did. He told me he was an engineer. That fits a stereotype of Asperger’s affecting kids of scientists and engineers — the so-called “geek syndrome,” nerdy brainiacs hooking up to somehow spawn a generation of kids with “autism lite.” I asked him what kind of engineer his father was. The answer: a mechanical engineer who tested guns for the Navy at the time he was born. And where was that? At what is now the Naval Surface Warfare Center in White Oak, Md. — just a hop and a skip across I-95 from the Beltsville agriculture center.

The coincidences are there for the noting, if one simply puts one’s commonsense to it. But building one’s argument out of so many coincidences that seem to be correlated, that seem to portend causation, is less an application of the scientific method than a use of a logic of coincidence, of chance construed into narrative; of coincidence as a sign of truth. There may well be some truth in the similarities that Olmsted notes in Cases 1, 2, and 3, but his suggestion that these similiarities that seem like coincidences reveal something more—that they all point to ethyl mercury poisoning in the first children identified as autistic—seems to me more the sort of thinking one finds in an ancient Greek tragedy in which the hero-protagonist (Oedipus Rex, Achilles) is subject to the greater, and mysterious, workings of Fate. Tyche is the ancient Greek word for “fate” or “chance” while syntychia—”chance occurring together”—-means “coincidence.” So it is a “coincidence” that Oedipus one night meets a stranger at a crosswords and kills him, and that that stranger is his real father, King Laios. It is a chance meeting that seals Oedipus’ fate. Tyche meaning “fate,” can seem (in Greek literature) to be a force overpowering any free will, any freedom, in a hero like Achilles to choose and direct the course of his life. Achilles knows that it is his fate to die young and gloriously, or old and forgotten and, on choosing the former fate, he can be said to conduct himself accordingly: Knowing that he will never return home to see his father, King Peleus, Achilles fights against the Trojans so that his fame, his kleos, will be sung about in generations to come.

The question is, does Olmsted—do proponents of the theory that mercury (for instance) causes autism—allow the coincidences he sees to overdetermine the presentation of his information?

When one is considering a theory regarding science, this might not be the kind of “authority” one ought to base one’s belief on.

(An abridged version of Bloom’s and Skolnick’s essay can be read at Edge; the full text (PDF file) can be accessed here.)

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POSTED IN: Adulthood, Cause, Classics, Myth, Psychology, Rhetoric, Science, Vaccines