A 2004 study in the journal Pediatrics showed that children exposed to television at ages 1 and 3 had decreased attention spans at age 7. It's a bit of a chicken-and-egg question, though.
"You can see how a kid who already has difficulty paying attention is put in front of the television to chill him out," Rich says. "It becomes a self-fulfilling prophecy."
Toddlers also sometimes struggle to translate what they see on two-dimensional screens to the three-dimensional world. (Check out the YouTube video "A Magazine Is an iPad That Does Not Work," in which a 1-year-old seems to get confused as she swipes her finger on a magazine, trying to move the pictures around.)
"Kids learn by doing, not by watching," says pediatrician Howard J. Bennett of Chevy Chase Pediatrics in Washington. "People once thought videos like Baby Einstein were good for kids too, and that's out now."
Giving children iPads to play with could also backfire, Bennett warns.
"Screens have this addictive quality, so when you take it away," he says, the kids "will probably cry".
Allison Mistrett, the founder and director of Leaps and Bounds, a paediatric occupational therapy practice, says she has seen children master Where's Wally? on an iPad but struggle to find their shoes in a crowded room.
Similarly, Rich says that many toddlers enjoy finger painting apps, but he questions whether the two-dimensional version trumps the real thing.
"The iPad does not give you that great feeling of paint squishing through your fingers," he says. "As much of a pain as that is for parents, think how much kids are learning about cause and effect. Not only can they draw pictures, they can make their hair all green and get a real reaction from mum."
Bennett has seen some practical benefits to iPads, however. Some toddlers watch movies while receiving shots in his office, which is helpful because distraction is one of the best tactics for dealing with pain at that age.
He generally advises parents to follow the AAP's recommendation that children over 2 should limit screen time to less than one to two hours per day.
"[Screens] should be a position of last resort," he says. "It's OK to let a toddler use a screen for 15 to 30 minutes once a day if a parent has to make dinner and has no other way to keep the child occupied and safe."
Tonia Sanders, a stay-at-home mother and blogger, doesn't see the harm in young kids' using technology. Each of her daughters, ages 3 and 6, has an iPhone, and the older girl got an iPod Touch when she was 2. Both girls also play with Sanders' iPad.
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