If I correctly understand Dr. Taylor's explanation of the brain in her talk that I linked to in the last post, counting beats when you practice might make playing music an activity that encourages optimal use of both sides of the brain. Her discussion about the chatter that goes on in the left side of the brain explains why it is possible to let the mind wander and think about all sorts of "other things" when practicing and performing even complicated music. The right side of the brain takes care of the physical stuff and enjoys the present moment, so it might not notice that what I am playing might happen to be sloppy, rhythmically or otherwise; but the tape recorder does notice.
In order to make practicing more productive, I think that I will attempt to turn my chatter track into something useful, like always counting and subdividing beats, something I don't always remember to do when I think I know a piece of music well. Maybe it will help develop the left side of my brain a bit. I know that it will improve my playing.