According to Common Sense Media, any time children spend in front of a screen, whether it's a television or a tablet, cuts into time when they could be interacting with the real world. Truglio recommends that parents make sure their young child spends no more than 1.5 to 2 hours a day in front of any kind of screen, reports LiveScience.
If you do let your child use apps on a tablet or smartphone, be sure to preview the app to make sure it's age-appropriate. Test to see whether or not your toddler is at a level where he or she can interact with it appropriately. Truglio notes that children younger than two should not use apps that teach letters, for example. Also, try playing with the app together, Truglio recommends. And don't let playing with apps be part of a daily routine, such as always giving your child the iPad when in the car.
What about educational DVDs? A study published in 2010 found that toddlers exposed to DVDs and videos marketed as "educational" showed no greater improvement in their vocabularies than children not exposed to such programming. "If you want to show your infant 'baby videos,' that's fine. Just don't expect the child to learn a great deal from it," said lead author Judy DeLoache of the University of Virginia.