Date of this Version
Published in Journal of Comparative and Physiological Psychology 67:3 (1969), pp. 364-369.
The effects of CS1 duration, partial reinforcement, and trace conditioning on second-order conditioned suppression were investigated, employing 64 rats as Ss. In Experiment 1, the clearest second-order conditioning was obtained when CS1 duration was the same during both the first- and the second-order conditioning phases of the experiment. In Experiment 2, somewhat better second-order conditioning was obtained when first-order conditioning had been under conditions of partial reinforcement, delay CS-US pairing. In neither experiment were CS1 suppression and CS2 suppression during second-order testing well correlated. This aspect of the results raised the question of the influence of nonclassical conditioning factors on the conditioned suppression measure of emotional conditioning.