That's a possibility, Linebarger said, though she issued a few words of caution. First, the study included only 51 children from mostly middle- to upper-class families. Second, the data were collected from the fall of 1999 to 2001, before "Sesame Street" decided to keep story lines together instead of jumping in and out of them throughout the program. (Incidentally, Rosemary Truglio, vice president for education and research at Sesame Street, said that the format was changed because the average age of the show's viewers was getting younger. In the early days, as a kindergarten-readiness program, Sesame Street targeted 4 year olds. Today, she said, the target audience is 2 to 4 years old.)
The study also hints at some positive aspects of TV. Some programs seemed to help children learn to use language. Linebarger's research shows that 30-month-old children who watched shows with strong linear story lines, like the relatively new "Dora the Explorer" and "Blue's Clues," had stronger vocabularies and used more-expressive language than their peers who didn't watch those programs.
Although I could take consolation in the fact that Janelle had started to choose Dora over Dorothy (the dinosaur in "The Wiggles"), I was no longer so naïve to believe that simply because a show appears on a children's channel means it is harmless. It seemed worth avoiding exposure to "Teletubbies."
But it was my conversation with Anderson that led me to reconsider our entire family's viewing habits. Background television could be doing harm, he said.
He first considered its impact more than 10 years ago, when he was working from home and caring for his year-old daughter. The Branch Davidians standoff in Waco, Texas, was erupting, and he had been watching CNN all day. "She was just playing in front of the TV," he said of his daughter, "and it just occurred to me: I wonder if this is having any effect on her?"
Since then, he has observed how children play when the TV is on and when it's not. Around two years of age, children start to talk out loud about what they are doing, often in words that adults cannot understand. Those conversations, Anderson and others surmise, are the nascent forms of the voice that older children and adults hear in their heads as they plan their next steps. He has documented that even if toddlers seem oblivious to the sounds and images of a video screen, their conversations are halted and the play time with toys is shortened when the TV is on.
"Background adult television is really quite disruptive to the organization of toddlers' toy play and quite disruptive to parent's interaction," he said.
Taming the Beast
Now I was faced with a dilemma: While watching "Dora the Explorer" (a show that Anderson, incidentally, played a role in designing) sounded like a worthwhile activity for my older daughter, the fact that the television was on at all might have a negative impact on my younger one. And those Saturday afternoons when we all played on the family room floor while college football flashed on the big-screen TV?
Suffice it to say that parenting perfection has not yet arrived at our house. But we are making changes. Janelle, now 2 1/2, is allowed no more than an hour of television a day, and we try to make sure her younger sister is napping or playing in another room when she watches it.
To avoid the "I want to watch TV!" tantrums -- yes, we are now blessed with such things -- we are consistently enforcing new rules, like no television before getting dressed and having breakfast.
We prefer videos over television, since they usually have stronger story lines and give us discipline when we lack it. (Namely, they come to an end.) Meanwhile, my husband and I avoid most grown-up programs until the kids have gone to bed.
Indeed, as long as the limits are enforced, we seem to be in a sweet spot. At 8 months, the baby is not yet attracted to TV and Janelle is now old enough to benefit from a few shows. But it won't be long before the baby will become an 18-month-old pining for Elmo.
And until more research clears up the questions about the attention-deficit study, I know that some days, when circumstances seem to scream for it, I won't be able to keep myself from reaching for that Sesame Street Sing-a-Long video.
But I will also buy some more Play-Doh.
Lisa Guernsey has written for the New York Times, Consumer Reports, the Chronicle of Higher Education and other publications.