Other clues regarding possible adolescent-peculiar responsiveness to rewards may be gleaned from focusing on how adolescents are motivated by rewards – i.e., by investigating potential age differences in the process of incentive salience. The concept of incentive salience, or “wanting,” has been greatly popularized by Robinson & Berridge (Robinson & Berridge, 2003, 1993, 2008), with “wanting” referring to goal-directed behavior towards relevant environmental stimuli. Organisms need a process to recognize and seek rewarding stimuli in the environment, such as food and water, to ensure survival. According to this hypothesis, the process of incentive salience is responsible for attributing motivational value to cues associated with natural rewards and drugs (Robinson et al., 1998). Importantly, it has been hypothesized that drugs of abuse are capable of hi-jacking the processes responsible for attribution of incentive salience, which were originally in place for the purpose of obtaining natural rewards (for review see Robinson & Berridge, 2003, 1993, 2008). Specifically, when repeated encounters with drugs induce behavioral sensitization, sensitization of incentive salience for drugs and drug-associated cues (through neural alterations in reward-related brain circuitry) is also thought to occur—a phenomenon termed “incentive sensitization” (Robinson & Berridge, 1993, 2008).
