The effect of two ways of devaluing the unconditioned stimulus after first- and second-order appetitive conditioning.
Rats received first- and second-order conditioning based upon a food unconditioned stimulus (UCS). They then received one of two manipulations designed to reduce the value of that food, satiation, or pairing of food with high-speed rotation. The effects of these manipulations were assessed during extinction tests of the conditioned stimuli (CSs). Compared with controls, both manipulations reduced the activity produced by the first-order CS but did not affect that produced by a second-order CS. The results are interpreted as consistent with those from aversive UCSs in implying the involvement of a UCS representation in first- but not in second-order conditioning. They also suggest that a major effect of satiation is to reduce the value of the UCS.
D000161:Acoustic Stimulation; D000818:Animals; D001244:Association; D003214:Conditioning, Classical; D005108:Extinction, Psychological; D005247:Feeding Behavior; D005508:Food Deprivation; D008297:Male; D009043:Motor Activity; D010775:Photic Stimulation; D051381:Rats; D012399:Rotation; D012527:Satiation