A study published in the journal Pediatrics in April 2004 looked at how watching TV impacts very young kids. In this study, 1- and 3-year-olds were assessed for their abilities to maintain their attention, and their parents were surveyed regarding how much TV they watch each day.

This study showed that for every hour of TV a child watches each day — regardless of the content — the risk of having attention problems by age 7 goes up 10 percent. Though this study doesn't prove that TV causes AD/HD, it does suggest that TV may increase inattention in some people.

Another fact that came out of this study is that only 37 percent of the 1-year-olds and 7 percent of the 3-year-olds didn't watch any TV. The American Academy of Pediatrics recommends that children under age 2 watch no TV at all.