Is extinction the hallmark of operant discrimination? Reinforcement and S(Delta) effects.

Using a successive discrimination procedure with rats, three experiments investigated the contribution of reinforcement rate and amount of S(Delta) exposure on the acquisition of an operant discrimination. S(D) components and were always 2 min in length, while S(Delta) (extinction) components were either 1 min or 4 min in length; responses in S(D) were reinforced on one of four schedules. In Experiment 1, each of eight groups were exposed to one possible combination of rate of reinforcement and S(Delta) component length.