WASHINGTON — Children who live in homes where the television is on most of the time may have more trouble learning to read than other kids, a study says.

Tuesday's report, based on a survey of parents, also found that kids 6 months to 6 years spend about two hours a day watching television, playing video games or using computers. That's roughly the same amount of time they spend playing outdoors and three times as long as they spend reading or being read to.

The study, by the Kaiser Family Foundation and Children's Digital Media Centers, found about one-third of children 6 and younger have TVs in their rooms and a similar proportion live in homes where a television is on most or all the time. In those "heavy TV households," 34 percent of children ages 4 to 6 can read, compared with 56 percent in homes where the TV is on less often.

"Watching TV is far inferior to playing with toys, being read to or playing with adults or talking with parents," said Dr. Henry Shapiro, chairman of developmental and behavior pediatrics at the American Academy of Pediatrics. "Watching TV without a parent is a junk experience, especially for young children."

The report found that 27 percent of 4-to-6-year-olds use a computer each day, spending an average of one hour at the keyboard.

Among kids in that age group, the report said half have played video games and one-quarter play several times a week or more. In a typical day, 24 percent of boys played video games compared with 8 percent of girls.

"These kids will have a great advantage in terms of how media can aid their learning, but parents must understand the pitfalls," survey researcher Victoria Rideout said.

Despite the heavy media exposure, the report found that reading continues to be a regular part of many children's lives. Almost 80 percent of those 6 and under read or are read to every day. Still, the report said, children spend only 49 minutes on average with books per day compared with 2 hours and 22 minutes in front of a TV or computer screen.

The report found parents have a largely positive view about TV and computers — 72 percent say computers mostly help in children's learning and 43 percent felt that way about television. Twenty-seven percent said TV mostly hurts kids' learning and 21 percent said it doesn't have much effect one way or another.

Shapiro said it isn't all bad that many kids are sitting in front of TVs, computers and video games.

"Kids are home, safe, they are learning things," he said. "This is just part of the process over history of using the new medium and this is giving kids a chance to be competitive in the world."

But, he said, there is a downside — so much time in front of TVs can cause kids to become fat, eat junk foods and not get enough sleep or adult interaction. "It all boils down to the involvement of parents as leaders and mentors and encouragers of their children's personal growth and learning," Shapiro said. "To the extent that children are being minded by machines is not a good thing, but children playing with technology is no different than the latest technology being crayons. It's just the latest technology."

The report is based on results of a national, random telephone survey of 1,065 parents of children ages 6 months to 6 years conducted from April to June. The margin of error is plus or minus 3 percentage points.