Smartphones are too stimulating for young children. Their brains are wired to really take in the lights, sounds and interactiveness of it all. This is kinda dangerous because this is also when a lot of learning is going on, they will develop socially based on the content they consume.

I’ve heard that some toddlers/babies recently began mimicing the action of pulling a mobile device from a pocket and looking down at the screen. They’ve seen others do it so often that they are learning it as a nearly instinctual action.