The ability of an extinguished CS and a CS given conditioned inhibition training to pass tests for inhibition

Conditioned inhibition (CI) is a classical conditioning procedure that results in a conditioned stimulus (CS) that predicts the absence of an unconditioned stimulus (US). A procedure known as Pavlovian conditioned inhibition training is the most common procedure for producing CI. In this procedure, a nontarget CS (CS A) is paired with the US and then CS A is presented with the target CS (CS X) without the US. Therefore, AUS trials and AX-noUS trials are given. CS X acquires inhibitory properties during these AX trials. Research has shown that extinction also produces CI. Extinction occurs when a CS (CS X) is paired with the US during conditioning and then this CS is presented alone without the US. The Rescorla-Wagner model predicts that the two CSs during AX-noUS trials will compete for learning and this should lead to slow and limited learning about those cues (a loss of excitation for CS A and inhibition acquired for CS X) due to this competition. During extinction trials, CS X does not compete for learning, so the subject should learn rapidly about the CS. The following experiments found that extinction produced less inhibition than Pavlovian conditioned inhibition training.