[dTal]

Interesting, thanks. That makes sense in retrospect and fits well with other research I'd heard of.

(tl;dr a wandering mind is good for creativity. Caffeine stimulates focus and inhibits mind wandering)

It's not quite a slam dunk though - the mind wandering is supposed to happen before the creative act. So I see no reason why going for a walk, then sitting down to write with a cup of coffee, should have any negative effects whatsoever.