The study by the Henry J. Kaiser Family Foundation also found that 43 percent of children under two watch television every day and 26 percent of them have a television in their bedroom.

The survey of 1,065 parents of children ages six months to six years old found that the youngsters spent about the same amount of time immersed in electronic media as they spend playing outside -- about two hours a day. That was well over the average 39 minutes the children spent reading or being read to, according to the study.

Among other findings: nearly half of children six and under have used a computer and 30 percent have played video games.

"It's not just teenagers who are wired up and tuned in, it's babies in diapers as well," the study's lead author, Vicky Rideout, said in a statement.

The study suggests that many children are growing up in homes where television is a constant companion. It found that 65 percent live in homes where the TV is on at least half the time, even if no one is watching.

Forty-three percent of parents said TV "mostly helps" children's learning and an overwhelming majority, 72 percent, said that computers "mostly help" children learn.