Very interesting. Was wondering, are there any differences in how independent they are at the same age? Have read that there is a possibility that the smartphone may be contributing to the development of children to be delayed by a year or two. For instance, are your younger children less interested in driving at the same age and doing things on their own.

... although, even if this is true, this could just be that kids seem to be more attached to their parents then they used to be (have read this as well).