The next time you pass by a shelf full of videos claiming to be educationally stimulating for babies, you might want to think twice before pulling out your wallet.

A new study suggests that watching television won't improve a baby's language or cognitive skills, even if they watch several hours a day.
"TV, in and of itself, doesn't seem to have an influence on cognition at age 3," said the study's lead author, Marie Evans Schmidt, a research associate at the Center on Media and Child Health at Children's Hospital Boston.
Results of the study were published in the March issue of the journal Pediatrics.
In 1999, the American Academy of Pediatrics began recommending that children under 2 years of age not have any screen time at all. But, more than two-thirds of American kids in the under-2 age group watch TV daily, and about 25 percent of those kids also have a TV in their bedrooms, according to background information in the study.
Almost 30 percent of parents responding to a recent survey said they felt TV or DVD viewing by children younger than 2 was educational and "good for the child's brain."
To assess whether or not TV has an effect -- positive or negative -- on babies' brain development, Schmidt and her colleagues included almost 900 children who were assessed at birth, six months of age, and then again at age 3. The researchers also asked the mothers to complete questionnaires on the baby's TV-viewing habits at six months, one year and two years. On average, the children watched 1.2 hours of TV a day.
After adjusting the data for numerous factors -- such as maternal age, income, education, marital status, whether there were siblings in the home, and duration of breast-feeding -- the researchers found that TV viewing wasn't associated with improvements in vocabulary testing or in visual motor abilities tests.
"I don't know why people think TV is good for babies. It's probably the way those products have been marketed," Schmidt said. "Although our study showed no evidence of harm, parents should be aware that infants watching TV may be at risk of obesity, sleep disturbances and possibly attention problems. We don't want this study to be viewed as a license for babies to watch TV because they won't be harmed. It might be that the effects don't show up until children are older."
Dr. Sara Hamel, a developmental behavioral pediatrician at Children's Hospital of Pittsburgh, called the new study "a very sound piece of research, and it looks to me like they did a good job of controlling the data for a number of variables that can influence child development, like parent education and income."
"This study answers a very specific question: For under 2s, does watching one hour or more of TV a day have an effect on cognitive outcomes? And, the answer is, no, being in front of the TV does not have an effect on some measures of language function and visual abilities," Hamel added.
A second study in the same issue of Pediatrics focused on whether or not adding violent-content labels to video games made those games more attractive to school-aged children and teens.
The warning labels had the opposite of their intended effect. Even for the youngest children in the study -- 7 to 8 years old -- a violent-content warning label made them want to play the game more, the U.S. and Dutch researchers found.