Leveraging cognitive neuroscience for making and breaking real-world habits

Habits can be understood as a balance between a stimulus-driven system based on stimulus–response (S–R) associations, and a goal-directed system based on action–outcome (A–O) expectancies (beliefs) and valued outcomes (goals).Habit expression is thought to occur when the influence of the stimulus-driven system outweighs the engagement of the goal-directed system, which can also explain suboptimal behaviors where people do not act in line with current beliefs and goals, such as action slips, impulsive behaviors, and compulsions.Making habits is facilitated by repetition, reinforcement, disengagement of goal-directed processes, and stable contexts.Breaking habits is promoted by weakening of S–R links, avoidance of habit stimuli, goal-directed inhibition, and formation of competing S–R associations.Beliefs and goals can also become habitual, which we refer to as habits of thought. Habits might therefore also result from goal-directed processes that automatically represent A–O expectancies and valued outcomes when presented with familiar stimuli.Obsessive-compulsive disorder, substance use disorder, and eating disorders are linked to deficits in goal-directed control, potentially explained by a transdiagnostic compulsivity dimension. Habits are the behavioral output of two brain systems. A stimulus–response (S–R) system that encourages us to efficiently repeat well-practiced actions in familiar settings, and a goal-directed system concerned with flexibility, prospection, and planning. Getting the balance between these systems right is crucial: an imbalance may leave people vulnerable to action slips, impulsive behaviors, and even compulsive behaviors. In this review we examine how recent advances in our understanding of these competing brain mechanisms can be harnessed to increase the control over both making and breaking habits. We discuss applications in everyday life, as well as validated and emergent interventions for clinical populations affected by the balance between these systems. As research in this area accelerates, we anticipate a rapid influx of new insights into intentional behavioral change and clinical interventions, including new opportunities for personalization of these interventions based on the neurobiology, environmental context, and personal preferences of an individual. Habits are the behavioral output of two brain systems. A stimulus–response (S–R) system that encourages us to efficiently repeat well-practiced actions in familiar settin