From a recent article:
There's some impressive new scientific research on your side when you tell your kids they can't possibly do their homework with the TV blaring, instant messenger crawling or MP3 player pumping. Unfortunately, explaining it will require you to get them unplugged from their iPods.The actual study is here.
Tell them this: A recent study shows that the ruckus of such multi-tasking may make them learn less, and to use the wrong parts of their brains to store information. Tell 'em they can look it up in the Aug. 1 issue of the Proceedings of the National Academies of Science (PNAS). Tell them it was done by researchers at UCLA (that's the University of California, Los Angeles, if they don't know).