Punishment persistence and sequence: Some effects of P-length and N-length in the rat

In a runway investigation, two groups of rats received partial punishment training with P-lengths of 1, 2, and 3 (Group P123) and P-lengths of 1 (Group P1), respectively. Two additional groups received partial reinforcement with N-lengths of 1, 2, and 3 (Group N123) and N-length of 1 (Group N1). An additional group was given unpunished continuous reinforcement in the runway, but received control shocks in a separate apparatus. Following training all subjects received punished extinction (shock plus nonreward). The results indicated that P-length increased resistance to punished extinction, however N-length did not have the corresponding effect. In addition, partial reinforcement did not increase resistance to punished extinction relative to continuous reinforcement. These results were interpreted within a sequential-theoretical framework.