Excitatory Backward Conditioning in Conditioned Punishment and Conditioned Suppression in Rats

Three experiments were conducted to examine the effect of assessment procedure, either conditioned punishment extinction or conditioned suppression reacquisition, on the associative outcome of backward conditioning in the rat. Each experiment consisted of three phases: (a) magazine and bar-press training; (b) Pavlovian training in which groups received one of backward, explicitly unpaired, or no presentation of a conditioned stimulus (CS) and unconditioned stimulus (US); and (c) either conditioned punishment or conditioned suppression transfer of training tests. In Experiment 1, backward conditioning resulted in excitatory associative effects during the conditioned punishment test. In Experiment 2, backward conditioning produced excitatory conditioning when assessed by a conditioned suppression reacquisition test. In Experiment 3, a number of backward conditioning parameters were manipulated, and backward pairings yielded facilitative reacquisition relative to the unpaired group, but did not differ from the no-treatment control group. The pattern of results suggests that backward conditioning produces qualitatively similar outcomes when assessed by a conditioned punishment extinction or conditioned suppression reacquisition test.