ANN ARBOR (CBS News) — Consumer groups are urging the federal government to investigate whether advertisers are taking unfair advantage of young kids using apps.

This comes as a new study found that 95 percent of the most downloaded apps for kids five and under target them with ads.

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For the study, researchers at the University of Michigan spent hundreds of hours playing 135 different games targeting young children, reports CBS News correspondent Anna Werner. They found advertising across the board, not just in video games, but also in apps marketed as educational.

In the Montague household, using apps is a part of every day life for 4-year-old Elliot and 7-year-old Ethan.

“The first thing in the morning when they wake up is they want to use their tablet time for the day,” mother Lisa Montague said.

But what some parents don’t realize is how many of their kids’ interactive games are littered with ads.

“There’s a bit of a Wild West right now in terms of the children’s app space,” University of Michigan assistant professor Dr. Jenny Radesky said.

Radesky is the senior author of a new study, which looked at more than 100 of the most downloaded apps on Google Play aimed at children five years and under. Researchers found those apps contained a variety of ads including pop-ups, in-app purchases and videos that interrupted play. Some of the ads were classified as “manipulative,” “deceptive,” and “disruptive,” with exposure to ads sometimes even surpassing time spent playing the games.

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“So there might be a little dancing present or a sparkling snowman and if you click on that as you would if you were a 5-year-old, an app ad would often show up,” Radesky said.

“It absolutely has the intent that the advertisers want. The kids will often come and say, ‘I want to download this game. I want this game. I want to try it out,'” Montague said.

The study also found that free apps which “may be more often downloaded and played by lower income children had a significantly higher prevalence of advertising.”

In a statement, Mountain View-based Google stood by its current policies saying, “Play apps primarily directed to children… must follow more stringent requirements, including content and ad restrictions… Additionally, Google Play discloses whether an app has advertising or in-app purchases, so parents can make informed decisions.”

“I think the one thing is personally monitoring their tablet time and not just letting them do it alone so often,” Montague said.

The researchers say apps for kids need greater government regulation. The maker of one of the apps mentioned in the study, “Talking Tom,” told us they’re responding to feedback that some of their games’ ads could be interpreted as misleading and are taking immediate action to make sure ads are clearly marked as such.

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The study’s senior author hopes the findings encourage parents to ask more questions about the games their kids are playing. She said parents should use the apps themselves first. If they’re getting bombarded by ads then they can make an informed decision about whether this is the best app for their child.