How does a deliberate action become an automatic habit? · Grey Matter

At first an action is goal-directed: it depends on the prefrontal cortex and the caudate (the associative striatum), and it changes as soon as its outcome stops being wanted.

How does a deliberate action become an automatic habit?

At first an action is goal-directed: it depends on the prefrontal cortex and the caudate (the associative striatum), and it changes as soon as its outcome stops being wanted. With repetition, and with dopamine marking each success, control shifts toward the putamen (the sensorimotor striatum), which chunks the sequence into a single unit triggered by its context. The habit then runs with little attention and keeps running even when its reward has lost value, which makes habits efficient and also hard to break.