Ontogenetic and phylogenetic shifts in the cognitive representation of the conditioned response

The retention of the conditioned response was tested in a retroactive interference paradigm using subjects from kindergarten, Grades 3 and 6, and college. The conditioned stimuli (CS) were either a tone or light, and the unconditioned stimuli (US) were vibratory tactual stimulations delivered to either the right or left index finger which produced a withdrawal response. Original AB learning consisted of pairing one of the CSs with one of the USs (e.g., tone-left). Interpolated CD learning consisted of pairing the other CS with the other US (e.g., light-right). When the first stimulus was presented alone to test for retroactive interference, the college students gave the response associated with it during original learning, the B response, but the kindergartners and third graders gave the D response, which was never associated with the CS during training. A second experiment used avoidance conditioning instructions and replicated these results while including rest-control and AD groups. These data suggest that what is learned by children in simple conditioning paradigms is different than what is learned by adults in the same paradigms. The results are discussed in terms of the following two hypotheses: (a) Russian theories of conditioning and extensions of Tighe and Tighe's and Kendler's theories of the development of perception and discrimination learning in children, and (b) theories of development of separability in perceptual development.