Exploring the relationship between actions, habits, and automaticity in an action sequence task.

It is tempting to equate the automatization of an action sequence with the formation of a habit. However, the term "habit" specifically implies a failure to evaluate future consequences to guide behavior. To test if automatized sequences become habitual, we trained rats on an action sequence task for either 20 or 60 d and then conducted reward devaluation tests. While both groups showed equivalent goal-directed performance of the trained action sequence on a global measure of behavior, sequence initiation and completion times were differentially sensitive to outcome devaluation in moderately and extensively trained rats.