Hauling the TV set out of a child's bedroom may help to boost his or her academic performance, three new studies suggest.

In one study of 348 children in Grade 3, 71 per cent had a TV in their bedroom. They scored between seven and nine points lower on standardized tests than their peers without their own TV.

In 1999-2000, students in California were surveyed in class about their use of media at home such as TV, computer, videotapes and video games, as well as how much time they devoted to homework and reading. Parents were also interviewed by phone.

Parents may want to think twice about putting an old TV in the kids' room when buying a new set.
Parents may want to think twice about putting an old TV in the kids' room when buying a new set.

Students who had a TV in their bedroom said they watched nearly 13 hours per week, compared to almost 11 hours for those who had to go to another room to turn on the tube.

"This study doesn't prove that putting a television in your child's bedroom will decrease his or her test scores, but it does add to the increasing evidence that it's not a good idea," said study co-author Dr. Thomas Robinson of Stanford University's School of Medicine in a release.

Those who had a home computer with internet access and no bedroom television had the highest test scores in mathematics and reading comprehension, the team reported in this month's Archives of Pediatric and Adolescent Medicine.

Parents in these homes may be more attuned to their child's education, or sleep differences may play a role, the researchers noted in a report titled The Remote, The Mouse and the No. 2 Pencil.

Robinson and his colleague did not find a consistent link between the amount of TV watched per week and lower test scores among the study participants, who had an average age of eight. Girls made up 53 per cent of those surveyed.

The effects of watching TV were found to be largely negative in the other two studies as well.

Viewing seemed to help in reading recognition and short-term memory for kids aged three to five but not reading comprehension or math, according to a study of 1,800 children over 10 years.

The net effect of viewing TV is "limited in its beneficial impact," wrote study author Frederick Zimmerman of the University of Washington. Before the age of three, watching TV may harm cognitive development, the study warned.

In the third study, researchers in New Zealand followed about 1,000 children until age 26. They found those who watched the most hours of TV as children and teens seemed less likely to finish high school, regardless of their IQ, socioeconomic status or behavourial problems in childhood.

It may be the type of programming that matters, according to a journal commentary accompanying the studies. Parents should be encouraged to turn to "well-produced, age-appropriate educational TV" to "stimulate children's cognitive development," wrote Ariel Chernin and Deborah Linebarger of the University of Pennsylvania.

The American Academy of Pediatrics meanwhile urges parents to limit children's TV viewing to no more than two hours per day. It recommends that those under age two watch no TV at all.