Figure 6. Amphetamine enhances the reinforcing efficacy of an auditory stimulus equally in sign-trackers (ST), goal-trackers (GT), and intermediates (IN).

Amphetamine increased the number of nose-pokes into the active (reinforced by the tone-cue) port. Amphetamine did not have systematic effects on nose-poke responding into the inactive port. Data are represented as mean (± SEM). There were no significant differences between STs and GTs. Asterisks denotes a significant increase compared to the saline-treated rats (0.00 dose).