Researchers at Cornell University published a paper earlier this month exploring a possible link between excessive television viewing by toddlers and increased risk for autism. The findings demonstrate that autism rates have risen with the introduction of cable television and programming specifically targeting young children, like Nickelodeon.
The full paper is available as a pdf file here. Gregg Easterbrook also has an article about the findings in Slate. Unless you are into 40+ pages of academic writing with tons of footnotes and graphs, you'll probably want to start with the Slate article. The findings are preliminary and definitely not bulletproof, as you'll see in the readers' comments to Easterbrook's article, but they're good enough to give me an excuse to banish the Teletubbies from my home.
[Photo Credit: "Tubi" by Juan Nosé]