One thing that bothered me a bit is that one could read into the story a bit of what I hope is an unintended message against treating attention deficit disorder. Having different background thoughts is all well and good until they interfere with ones ability to focus on the important thoughts in ones head. I know that it isn't in the story, but people who already mistakenly believe that you're turning a kid into a zombie by giving him medication to help cope with a real mental illness.
This will be slightly off-topic, but I feel I should chime in here, since this happens to be a subject that's sort of important to me. I suffer from (adult) attention deficit disorder. I also have a friend who worked at a lab researching ADHD. I know a lot about it, both from a scientific point of view and from a personal point of view.
For at least a large amount of people suffering from ADHD, the problem is *not* too much background thoughts. The problem is too little. There have been studies that show that brain activity associated with attention is like a wave - for all humans, it goes up and down on its own. And there is a thershold below which, if the attention drops, you can no longer maintain it. However -and forgive me for oversimplifying the neuroscience since I'm working from memory here - for most people, there's also a constant backdrop of "static", to use the story's term, that keeps it active. So, say your attention level drifts from 0 to 1, and that it has to be over 0.5 for you to keep attention. For people without ADHD, there's static running at level 0.4. So, their brain is really covering the range of 0.4-1.4, and they very rarely lose attention.
One hypothesis, which seems to match my own experience, for the cause of ADHD is that ADHD sufferers have *less* background static going on. So, the wave drops below "attention" a lot more. And the mechanism for dealing with this is hyperactivity - in essence, it's the brain's attempt to generate more static in order to be able to keep up with attention.
I can tell you that my experience fits with this. I cannot listen to someone, for instance, unless I'm also moving. If I'm sitting still I can't concentrate. I got through lectures - both undergrad and grad school - by brining in computer games to class. If I'm playing a game - ideally a platform game or something like zuma, which requires mostly motor responses but doesn't require puzzle-solving - my ability to understand what other people are saying goes *way* up. If I want to read something, I walk. If I need to write papers, I turn on the TV in the background. I need to introduce static, because it augments my attention, not takes away from it.
I don't know if this is true of all people with ADHD, but it's certainly true for me.