Avoidance responding in dogs trained in symmetrical or asymmetrical go, no-go differentiation.

The acquisition and the consolidation processes of avoidance responding in go, no-go differentiation with asymmetrical and symmetrical reinforcement procedures were studied in 49 male mongrel dogs. Differentiation training procedures with asymmetrical and symmetrical reinforcement were contrasted by the occurrence of painful shock on negative trials. The quality of conditioned stimuli and their relative saliency exerted strong effects on the rapidity of learning and the number of commision errors when the "asymmetrical" procedure was used, whereas these effects were strongly attenuated under "symmetrical" procedure of reinforcement. Dogs trained in "symmetrical" go, no-go differentiation showed characteristic responses executed with shorter latencies and larger percentages of errors on negative trials and numerous extra-and intertrial responding in early stages of differentiation learning. Retention tests showed a greater stability of acquired differential responding trained under "symmetrical" than under "asymmetrical" procedure of reinforcement. The data indicate that the strength of the secondary punishing effect of CS ;prolongation is directly related to the saliency of the stimulus. The relations between the primary and secondary punishing effects in the two types of differentiation task, and problem of signalling and arousing properties of stimuli used in training, were discussed.