Treatments that weaken Pavlovian conditioned fear and thwart its renewal in rats: Implications for treating human phobias

In experiments using a total of 144 albino rat subjects, the authors assess ed the ability of fear-weakening treatments to prevent fear renewal (relaps e). Conditioned suppression of operant behavior served as the measure of fe ar in an A-B-A (acquisition-treatment-test) renewal paradigm. In Experiment 1, 100 nonreinforced exposures to a feared cue during treatment (extinctio n) did not reduce fear renewal relative to 20 exposures. In Experiment 2, e xplicitly unpaired (EU) treatments thwarted both renewal and reacquisition. In Experiment 3, conditioned inhibition (CI) and differential conditioning (DC) treatments weakened renewal and resisted both reacquisition and a for m of reinstatement. In Experiment 4, EU, DC, and CI treatments all thwarted renewal. Evidence suggested that the ability of the treatments to do so re flected the combined effects of transfer of extinction across treatment and test contexts and habituation to the unconditioned stimulus.