does TV cause autism
[Gregg Easterbrook wrote this up on Slate today, but here’s the
original]
ABSTRACT
Autism is currently estimated to affect approximately one in every
166 children, yet the cause or causes of the condition are not well
understood. One of the current theories concerning the condition is
that among a set of children vulnerable to developing the condition
because of their underlying genetics, the condition manifests itself
when such a child is exposed to a (currently unknown) environmental
trigger. In this paper we empirically investigate the hypothesis that
early childhood television viewing serves as such a trigger. Using
the Bureau of Labor Statistics’ American Time Use Survey, we first
establish that the amount of television a young child watches is
positively related to the amount of precipitation in the child’s
community. This suggests that, if television is a trigger for autism,
then autism should be more prevalent in communities that receive
substantial precipitation. We then look at county-level autism data
for three states – California, Oregon, and Washington – characterized
by high precipitation variability. Employing a variety of tests, we
show that in each of the three states (and across all three states
when pooled) there is substantial evidence that county autism rates
are indeed positively related to county-wide levels of precipitation.
In our final set of tests we use California and Pennsylvania data on
children born between 1972 and 1989 to show, again consistent with
the television as trigger hypothesis, that county autism rates are
also positively related to the percentage of households that
subscribe to cable television. Our precipitation tests indicate that
just under forty percent of autism diagnoses in the three states
studied is the result of television watching due to precipitation,
while our cable tests indicate that approximately seventeen percent
of the growth in autism in California and Pennsylvania during the
1970s and 1980s is due to the growth of cable television. These
findings are consistent with early childhood television viewing being
an important trigger for autism. We also discuss further tests that
can be conducted to explore the hypothesis more directly.