I'll take a couple of guesses, not intending to try and step in for Alex, because a.) it wouldn't be right, and b.) I'm not a doctor.
I think the important word in his post was conditioned . No one watches plays for several hours a day, seven days a week, but lots of people do watch television that much. There is some connection between visual stimulation and the brain, I do know. There is a therapy that I can't remember the name of for the life of me (EMD,EMR?) , but it involves moving your eyes side-to-side from one point to another while thinking certain thoughts (say, to stop smoking), so that after a while when you move your eyes that way at any time, that thought pops into your consciousness.
A major concern I have about kids' shows--Sesame Street in particular; that's one I'm familiar with--is this conditioning. Never mind that it's set up to help them learn things; I can't help but wonder how it affects their ability to learn from other sources, say minor ones like school, and books. If they have been condtioned by three years of watching Sesame Street daily, how difficult will it be for them to focus on any lesson in kindergarten (and later) that lasts longer than 15 seconds? I wonder if anyone has ever done a study on that.
