The National Institute of Mental Health Research Domain Criteria (RDoC)
"Learned stimulus-response mappings triggered by internal or external stimuli that are autonomous of the current value of the outcome or goal. Habits may include overlearned sequences. Habits are implicit and efficient, requiring few cognitive resources, but can also be maladaptive under novel circumstances. Habits are based on previous positively or negatively reinforced learning and commonly occur after extended learning. Both habit formation and expression are commonly operationalized within motor control systems. When habit formation is motivated by reward learning it overlaps with the Habit construct within the Positive Valence domain."