However, Brown says, the fact that they are doodling means they probably are paying attention. "Doodling is a pre-emptive measure to stop you from losing focus." Research has shown that you retain information better when it is combined with some kind of stimulus. Doodling helps with retaining information, because when you are doodling it engages four types of stimulation: visual, auditory, reading/writing, and kinesthetic.
Doodling is "a portal to move people through higher levels of visual literacy."
I think doodling focuses the brain in the same way knitting, whittling, and kneading silly putty does. As a big-time fidgeter, I need to be doing something with my hands when I'm talking with people or I start to go nuts.