Autism in Children and TV
October 22, 2006
By Cornell University
A series of data sets suggest a
connection between early childhood television viewing and the
onset of autism, analyzed in a paper by economists at
Cornell University and Indiana University-Purdue University . And
the authors urge further investigation and research by experts in
the field of autism and TV viewing.
In a paper to be presented at a
conference of the National Bureau of Economic Research, Oct. 20, in
Cambridge, Mass., the authors reviewed data from the Bureau of Labor
Statistics' American Time Use Survey on TV viewership rates among
children and compared it with data from the National Climactic Data
Center, which looks at the amount of precipitation communities
receive.
This analysis showed that children
from rainy counties watch more television. When autism rates were
then compared between rainy and drier counties, the relationship
between high precipitation and levels of autism was
positive.
"We tested our hypothesis using
existing, well-known data," said Michael Waldman, a professor of
economics at Cornell's Johnson Graduate School of Management and a
co-author of the research paper. "The analysis shows that early
childhood television viewing could be an environmental trigger for
the onset of autism and strongly points to the need for more
research by experts in the field of autism."
Thirty years ago, it was estimated
that roughly one in 2,500 children had autism, while today some
estimate that number to have increased more than tenfold, to as high
as one in 166. At the same time, television viewing has increased
dramatically due to easy access to cable and satellite television,
more traditional broadcast offerings and the market penetration of
VCRs and DVDs.
Because there are no large data
sets that track whether children who watch a lot of TV when they are
young are more likely to develop autism, the authors examined the
connection between autism and two factors that generally increase
the amount of TV that young children watch: precipitation and access
to cable TV. They find that current school-aged children who live in
California, Oregon, and Washington counties that received large
amounts of rain and snow when the children were young are more
likely to be diagnosed with autism. Furthermore, children who grew
up in California and Pennsylvania counties during the 1970s and 80s
with high cable subscription rates were also more likely to be
diagnosed with autism. These analyses control for differences
between counties in income, population, and demographic mix - other
factors that may influence the autism rate - and also examine
changes in county autism rates over time as well as differences at a
point in time.
"Our analysis is not definitive,
but it certainly raises questions that seem to have gone unasked in
autism research to date," added Sean
Nicholson, an associate professor of policy analysis and management
in Cornell's College of Human Ecology. "The medical community is
increasingly convinced that something is happening in the
environment that triggers an underlying biological or genetic
predisposition toward autism, and these findings strongly support
the need for taking a closer look at early childhood television
viewing
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