The Effect of Intertrial Conditioned Stimuli in Autoshaping

Abstract

Three autoshaping experiments, using pigeon subjects, examined the effect of presenting an S+ or an S− on acquisition to a different conditioned stimulus (CS). Experiment 1 found that signalling intertrial food with an S+ or an S− allowed acquisition of responding to the target-CS; however, that acquisition was slower when the signal was the S+. Experiment 2 found that even when the S+ or S− were presented without food in the intertrial interval, acquisition was slower in the group receiving the S+. Experiment 3 found that a similar, but weaker effect occurred when the S+ or S− stimuli were presented in the session prior to target-CS training, rather than intermixed. These results have implications for the interpretation of experiments that use a signalling manipulation to assess the interaction of CS and context in Pavlovian conditioning; they suggest that signalling unconditioned stimuli (USs) may have consequences other than that of modulating context-US learning.