It's no wonder the American Academy of Pediatrics (AAP) recommends that parents limit children's TV exposure to no more than one to two hours of quality programming daily and not keep a TV in their child's bedroom. If there's any good news, it's that the study found heavy exposure in early childhood did not have enduring consequences if viewing habits were adjusted; children with early exposure only (less exposure at 5 1/2 years) did not have behavioral and social difficulties compared to children with heavy exposure at both ages.
Another study in Pediatrics, published three years earlier, suggests early television viewing (at ages 1 and 3) can contribute to problems with attention at age 7. The number of hours viewed per day was associated with an increasing risk of developing problems with attention span.
So-called "educational" programming may help children learn if parents don't have the time to teach them, but it doesn't seem to make them any smarter, according to a 2008 study, again in Pediatrics. Researchers concluded, "Contrary to parents' perceptions that TV viewing is beneficial to their children's brain development, we found no evidence of cognitive benefit from watching TV during the first two years of life."
Other studies suggest a clear link between television viewing in childhood / adolescence and lack of exercise and poor eating habits. After all, sitting on a couch all day doesn't leave kids with much time to exercise or eat right, especially when they're being bombarded with ads for chips, soft drinks and fast-food items.
The bottom line is, there are plenty of fun, stimulating ways to entertain your children while teaching them at the same time, and none of them involves staring into a television or computer screen.