Incentive Salience

Incentive salience is a motivational "wanting" attribute given by the brain to reward-predicting stimuli. This "wanting" is unlike "liking" in that liking is a pleasure immediately gained from consumption or other contact with stimuli, while the "wanting" of incentive salience is a motivational magnet quality of a stimulus that makes it a desirable and attractive goal, transforming it from a mere sensory experience into something that commands attention, induces approach, and causes it to be sought out.

It is often associated in the pathological situation when stimuli are associated with drug-taking behavior that through this begin to reinforce themselves. Thus, if a person's addiction is extinguished and he is then presented with a stimulus that has been associated with the drug in the past, a craving for that drug reappears. For example, anti-drug agencies previously used posters with images of drug paraphernalia as an attempt to show the dangers of drug use. However, such posters are no longer used because of the effects of incentive salience in causing relapse upon sight of the stimuli illustrated in the posters.

Dopamine may also have a role in the salience of potentially important stimuli, such as sources of reward or of danger, although its role in experiencing pleasure (distinct from appreciating salience) has been questioned by several researchers. This hypothesis argues that dopamine assists decision-making by influencing the priority, or level of desire, of such stimuli to the person concerned.

The incentive salience theory of addiction suggests that "liking" (hedonic value) of a drug may be dissociated from "wanting" the drug due to increased incentive salience. In fact, if the incentive salience associated with drug-taking becomes pathologically amplified, the user may want the drug more and more while liking it less and less as tolerance develops to the drug's pleasurable effects. Proponents of this model argue that this explains the development of uncontrolled addictive behavior, which is not motivated by the hedonic value that caused acquisition of the habit in the first place.