To the extent that greater consumption of natural and drug rewards during adolescence is associated with enhanced incentive salience for reward-related cues, adolescents would be expected to exhibit greater sign-tracking behavior relative to adults. In initial work to examine this hypothesis, adolescent and adult male rats (with 12 animals per age group) were placed into an autoshaping situation, with an 8-sec presentation of an illuminated retractable lever preceding response-independent delivery of a banana pellet. Rats were given 25 lever-pellet pairings each day, for a total of 5 days. Over time, some rats approached and contacted the lever CS upon its presentation (“sign-trackers”), whereas other rats approached and entered the food trough when the lever was inserted into the chamber (“goal-trackers”), even though contacts with neither the lever nor the food trough impacted delivery of the food reward. Although the adolescent and adult age groups both contained certain animals that displayed evidence of sign-tracking, adolescents overall showed significantly weaker sign-tracking than their adult counterparts (see Fig. 1). This adolescent-associated reduction in sign-tracking behavior is also evident in female rats (Doremus-Fitzwater &
