2 experiments tested the notion that respondent and operant processes in avoidance learning can be dissociated. Exp. I with 33 female albino rats showed that (1) prior unavoidable shocks facilitated subsequent acquisition of a simple avoidance response in Ss, and (2) distributed unavoidable shock had a greater facilitatory effect than a long single unavoidable shock. Exp. II with 45 female albino rats showed that overtraining of the avoidance response prior to its extinction facilitated subsequent reacquisition of the avoidance response. These results support O. H. Mowrer's (see 26:6) 2-factor theory that avoidance learning involves (1) Pavlovian fear conditioning, and (2) operant learning of the avoidance response, and that the 2 factors can be manipulated independently. (PsycINFO Database Record (c) 2006 APA, all rights reserved)