Wednesday, January 6, 2010

What Causes Autism

Reuters:
U.S. researchers have identified 10 locations in California that have double the rates of autism found in surrounding areas, and these clusters were located in neighborhoods with high concentrations of white, highly educated parents.

Researchers at the University of California Davis had hoped to uncover pockets of autism that might reveal clues about triggers in the environment that could explain rising rates of autism, which affects as many as one in 110 U.S. children.

Instead they rediscovered that the squeaky wheel gets the grease.

2 comments:

Unknown said...

I presume that you only intend a joke here, but I feel compelled to comment, because I've grown increasingly skeptical of this sort of response. In fact, of course, the researchers only discovered that clusters of autism "were located in neighborhoods with high concentrations of white, highly educated parents." One may hypothesize that things are this way because of the "squeaky wheel" syndrome, but that is only a hypothesis, waiting to be proved or disproved.

For one thing, if the squeaky wheel hypothesis is right, one has to ask in what sense. Is the clustering the result of affluent parents overdiagnosing their children, or of poorer parents underdiagnosing theirs? Is the source of evidence used a factor? (For example, did they use state records, in which case one can wonder if poor folks tend to keep quiet about such things, or if they report them, they report them to their churches, and churches in poor neighborhoods are more likely not to recommend turning to the state, etc.). But one also needs to consider the possibility that the finding represents some reality that is not merely an artifact of class differences of one sort or another. When were the neighborhoods built? One can hypothesize that a chemical was used in upscale suburban building from a certain era that has some effect. Or that affluent white parents grew up with some chemical that caused autism-linked mutations in their reproductive material. Or that whites, or some subgroups of them, are actually more prone to autism. What is the ethnic background of the whites in question? That's another avenue that should be investigated. Perhaps some immigrants came from still-relatively-closed rural European communities that had concentrations of autistic susceptibility. One could go on and on.

My real point is that sometimes the wise, knowing response is right, but often it is misguided. For example, it's probably pretty safe to assume that the recovered memory movement of the eighties was not uncovering evidence of real rampant ritual abuse. But remember what Ascherson says about Herodotus: for centuries, the "wise" consensus was that he was lying in his stories about the Scythians and others. But archeology has tended to prove him trustworthy on many, many points.

John said...

Indeed my response was rather flip, but it was not entirely a joke. My first guess is that educated parents know that the key to getting medical care for their children or special help from the school system is a recognized diagnosis, so they are the ones who seek out a diagnosis for their children.

I have not read this study, but the authors are serious epidemiologists who set out to look for environmental factors. They found none. The one thing they point to that might cause autism rates to be higher in educated neighborhoods is that educated parents tend to be older, and there is some evidence that autism is more common among the children of older parents. Otherwise, so far as they could tell, differences in the rate of reported autism cases are caused by differences in reporting, not the environment.