The Zimmerman et al. article* points out that shows like Blue’s Clues, Sesame Street and Barney provide real educational benefits for children 2.5 – 5 years old, but that nothing has been shown to be valuable for child under the age of 2. Despite this utter lack of evidence though, a wide range of educational videos are marketed at children under 2. Despite a total lack of evidence, the companies marketing these videos make claims about their efficacy:
Notwithstanding the paucity of evidence for cognitive development benefits of early viewing of DVDs or videos, claims have been made for such benefits.2 Approximately 3/4 of the 100 top-selling infant videos on Amazon.com in 2005 made educational claims, both explicit and specific.2 For example, one product targeted at 0- to 2-year-olds claimed that the video will “teach your child about language and logic, patterns and sequencing, analyzing details and more.”2 [Zimmerman et al., p.1]
This reminds me of nothing so much as the “nutritional supplement” industry, where all sorts of wild claims can be made. Of course, unlike these products, nutritional supplements are forced to say (somewhere, in small print) that the claims they are making are unproven. The standards for educational products, it would seem, are far lower.
As for why these products actually hurt children’s vocabularies, Zimmerman et al. go into a bit more depth here than in the news story. They propose three explanations
- Poor language development motivates parents to purchase these types of products
- Residual confounding: that some factors unmeasured by the study played a role
- That the DVDs actually hurt language development, and were directly responsible for the 17-point difference in vocabulary.
It’s really remarkable that there haven’t been more studies of products like these. I suppose they have a commonsense appeal to people. But what about the designers of these products – are they designed in keeping with well-established ideas about cognitive development in the under-2s, or did they just try to copy what has worked with older children? Or did they just take a “commonsense” approach? I find it remarkable that studies like this haven’t been done sooner, and haven’t been done by the people who make these products – after all, it would be in their interest to say that their product works better than Product X.
Zimmerman et al. end by calling for experimental trials to see if they can confirm the findings of their correlational study. But who would want to take that chance? While the study suggests that the harm done by these products is transitory, it still seems like a rather large chance to take. The ethics of exposing children to something like this seems rather questionable, if you suspect that it might be harmful.
*Zimmerman, Frederick J., Dimitri A. Christakis and Andrew N. Meltzoff. 2007. Associations between Media Viewing and Language Development in Children Under Age 2 Years. Journal of Pediatrics, in press.