In Raphael’s “Vision of a Knight” (http://www.nationalgallery.org. uk/paintings/raphael-an-allegory-vision-of-a-knight), a sleeping figure dreams of the two paths offered to him. On the left is Virtue, with a long winding road leading up to a castle representing earthly success; on the right is Pleasure, holding a flower. He must choose between immediate reward versus hard work and the promise of future riches. Although Raphael’s knight appears anything but conflicted, the type of self-control he faces is felt to be mentally demanding. The notion of self-control is paradoxical because it implies that there are two “selves.” However, it is ubiquitous in art, psychology, and neuroscience, likely because we all experience it regularly. Self-control feels effortful. The experience of impulses needing to be reigned in is familiar to the shopper, the dieter, the addict, and the student faced with homework. Plato viewed the soul as a chariot pulled by winged horses (the passions) and controlled by a driver (reason), and the notion of a conflicted self has found expression in almost all conceptions of human behavior since then, up to modern psychology, economics (1), and cognitive neuroscience. Most dual-systems accounts suggest the existence of one system that makes decisions rapidly and automatically and is especially influenced by emotional processes such as reward anticipation and one system that is more deliberate and incorporates long-term goals. Some models have the more deliberative system inhibiting reward-seeking drives. Impulsivity, a tendency to act rashly without consideration of consequences, would be the interaction of strong incentive drive with impaired (or weak) inhibition. Perhaps the most obvious expression of this model is drug addiction, where it literally seems as if there are two competing desires: one for the drug and one for abstinence, with their interaction experienced as conflict. Vulnerability to addiction is often conceptualized as an interaction between an enhanced incentive response to drug use opportunities (including cues) and reduced self-control. These cognitive functions are linked to two sets of brain structures: targets of mesolimbic dopamine (nucleus accumbens, amygdala, insula, orbitofrontal cortex) for reward and motivation and lateral prefrontal cortex and anterior cingulate cortex (ACC) for self-control. A third set of regions, referred to as the salience network and centered in the anterior insula and ACC, may be implicated in coordinating or switching between the two systems (2). Converging evidence linking poor inhibitory control to substance use comes from several research domains, including personality research (3), cognitive neuroscience, and brain imaging. Personality research has identified an externalizing spectrum, characterized by persistent difficulty in controlling impulses, which underlies several conceptually linked syndromes, such as alcohol use disorder (AUD), childhood conduct disorder