| Abstract: | Four experiments that compared the aversion acquired by 599 18- and 60-day-old Sprague-Dawley rats to a flavor that was either tasted alone or in combination (simultaneously or successively) with another flavor when paired with illness were conducted to study temporal variables and theoretical issues pertinent to potentiation and overshadowing while investigating ontogenetic differences in these phenomena. Results show that when either preweanlings or adults were presented with a simultaneous compound flavor (sucrose/coffee) followed by LiCl-induced illness, greater sucrose aversions were found than for Ss conditioned on sucrose alone. Preweanlings demonstrated greater potentiation than adults, whether the CS–UCS delay was 0 or 1 hr. This potentiation was eliminated by nonreinforced presentations of the alternative CS element. Potentiation was not observed when the 2 flavors were presented successively as the CS; instead, overshadowing occurred. Tests of configuring by extinction procedures indicated a tendency for these Ss to form a configured representation of the simultaneous compound solution. This disposition for configuring was more pronounced for preweanlings than for adults. Ontogenetic differences in response to configuration, CS saliency, and generalization decrement were consistent with the observed ontogenetic differences in potentiation. (33 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved) |
