When I play too much tetris I start thinking about the blocks all the time and find it maddening. I wonder if these guys can ever stop thinking about the blocks or if it just becomes so hard-wired in their brain that they lose consciousness of it.
My impression is that these players are spending a lot of their conscious energy on the next-piece box, constructing the stack, and just staying calm. I think the majority of what they're doing is near instinct at this point, since they play so much, they just kinda "know" the right move for any given situation. Or at least, most of them. A max out game is a combination of random luck and extreme skill/practice.
The documentary "Ecstasy of Order: The Tetris Masters" (steaming free on Hulu) has more on all of this. Disclosure: I wrote parts of that film. Ben Mullen is one of the main subjects of the film.
Either that, or I have officially lost it. (Or both; they are not mutually exclusive...)
That corresponds with my experience with the Tetris Effect from other games. I used to play a ton of DDR, and initially experienced the same phenomenon (as I've mentioned in a past comment, I took the SAT the day after buying and playing it all night, resulting in the fascinating experience of seeing DDR arrows superimposed over an SAT scantron). I was pretty heavily addicted to the game for a long time, but eventually the phantom arrows simply went away.
- When I studied Descriptive Geometry I started seems projections everywhere I looked.
- When I was doing research and development on procedural buildings, shapes appeared whenever I looked at real buildings.
- When I was studying graph theory (and I basically drawn everything to help me remember) I could see blobs appearing on the tv screen for random shapes.