For some time now I`ve noticed how Padraig Harrington bites his tongue during and after his swing . I guarantee if you watch him next year you`ll notice this, especially when holding the followthrough(you`ll see it pertrude). Apparantly, when asked about this, he commented on how he`d been advised to do it, as it aids concentration. I agree with shootin4par that this destraction stops the brain from thinking about too many things, but maybe the tongue in particular, influences conscious thought, in the same way that it`s imperative for speech.