Inhibition of Shuttlebox-Avoidance Behavior Resulting from a Reduction in the Magnitude of Reinforcement

Abstract

Three experiments studied inhibitory conditioning in an unsignalled shuttlebox-avoidance preparation with rats. Following a Pavlovian conditioning phase and using a summation test in which test stimuli were superimposed on a previously established ongoing shuttlebox-avoidance response, it was found in Exp. 1 that a light could be established as an inhibitor of avoidance when it signalled the absence of shock. Exp. 2 established that a light could become a conditioned inhibitor when it signalled a reduction in shock intensity rather than its complete absence. Exp. 3 confirmed this general finding but did not yield differential inhibitory effects with different degrees of reduction in shock intensity for the particular parameters chosen. The findings can be adequately interpreted in terms of the Rescorla-Wagner model of conditioned inhibition.