Craving Hinders Comprehension Without You Realizing It

So we must only have a percentage of Free Will based on our physical resources..... 

ScienceDaily (Dec. 8, 2009)

A new University of Pittsburgh study reveals that craving a cigarette while performing a cognitive task not only increases the chances of a person's mind wandering, but also makes that person less likely to notice when his or her mind has wandered.