Resistance to extinction as a function of amount of pretraining in a free-operant situation

Two groups of five albino rats were given either no dipper training (NP) or four days of dipper training (P) in a free-operant situation, then alt Ss were given 25 days of bar-press training. Acquisition was followed by six days of extinction. Results showed both more rapid learning and more rapid extinction of the bar-pressing response by the P-group. However, the extinction results depended on the measure employed.