Almost all free and paid-for apps aimed at children aged between 12 months and five years of age contain advertisements of varying levels of intrusiveness, according to researchers at the University of Michigan in the US.

Delving into these apps, it was found that 42 per cent included use of commercial characters such as Lego Duplo or Paw Patrol, while 35 per cent had pop-up video ads interrupting gameplay. Meanwhile, 30 per cent had ads nudging them towards in-app purchases and 28 per cent encouraging the user to rate the app. Researchers also found that apps labelled as “educational” – and therefore more likely to be trusted and downloaded by parents – had the same high level of ads as other categories.

“Our results suggest that app stores could play a crucial role in making higher-quality apps more easily accessible to parents and children (ie, highlighted and prioritised on the top of their webpage or app store, where children are more likely to click them),” say the researchers.

"It is important that Google Play and iTunes be transparent with families about the apps they offer and not misrepresent that apps meet certain privacy or educational criteria, which may lead to a false sense of security among parents."

[ Advertising in Young Children's Apps: A Content AnalysisOpens in new window ]