I think what is happening is we are reinforcing those mental functions and even down to those mental circuits that make us good and skimming and scanning and there has been certainly studies that show our visual acuity and improves that as we use video games but there is no encouragement, there is no reward for the more attentive mode of thoughts, for contemplation, for reflection, for introspection, for deep reading and neuroscientologists tell us that when we don't practice different ways of thinking we lose those, even down to the point that the circuits begin to weaken in our brain, if not eventually dissolve. 