Sure, we know not to plop our kids in front of Spongebob to keep them occupied — er, right? But what about that background TV that so many of us turn on, leave on  and forget about?

New research shows that the mumbling of news anchors or the cheering of “Ellen” audiences has a majorly negative impact on babies, even if they are not engaged with the show itself.

The authors studied children ages 12 months, 24 months and 36 months who were in a room with toys and a television. The television would be on for a half hour with a show that was geared toward adults, and off for a half hour. Parents did not have to watch the show while it was on. Then the researchers observed how parents interacted with the children.

The findings were quite clear: When television was on, parents “uttered” words 6.35 times per minute. No TV? 9.36 times. Words per minute when the TV was on in the background (i.e. no one was actually watching it): 24.24. When the TV was off: 35.89 words per minute. And as for new words (“big” words that the children didn’t know yet), which obviously help a child become a talker: 6.42 when the TV was on versus 7.97 with no TV.

“We found that there was a change in the quantity of speech they were directing at kids,” said co-author Tiffany Pempek, assistant professor of psychology at Hollins University in Roanoke. “There were not as many words when the TV was on, or not as many sentences or phrases. And we found some quality was affected. There were not as many new words.”

Hearing parents speak has a huge impact on children’s developing language, and it has a positive effect on cognitive development as well, she said.

“The research certainly suggests that, taken together with other research, we have enough evidence to say parents should limit background TV,” she said. “Other research is showing that babies up to 2 years of age have about 5.5 hours of [background] TV a day. That’s a lot, especially considering how much they sleep. It is important for parents to be aware and try to limit background TV and turn it off when not watching.”

Parents anecdotally told the researchers that they didn’t think having television on in the background was a big deal because their baby wasn’t looking at a TV screen. “But our research shows it’s influencing their play and their parent-child interaction, as well as language,” Pempek said.

Pempek mentioned that she herself has small children.  She knows there is a lot of research out there telling parents what not to do. “I don’t want them to feel guilty and like this is just another thing that I shouldn’t be doing. But if you can cut it back, that is useful for child.”

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