Five undergraduates responded under a fixed-ratio (FR) 145 schedule, and 5 others responded under a differential-reinforcement-of-low-rate (DRL) 20-s schedule. Both groups were then exposed to a differential-reinforcement-of-rates- with-pacing 1 s less than interresponse time (IRT) less than or equal to 2 s schedule. Following this, probe sessions under fixed-interval (FI) 20-s, variable-interval (VI) 20-s, and FR 145 schedules were interspersed among baseline sessions of the 1 s less than IRT less than or equal to 2 s schedule. Response rates under the FI and VI schedules were higher for participants with a history of the FR schedule than for those with a DRL history. Under the FR schedule, such a systematic difference by remote histories was observed only during the first of the 3 probe sessions. (Contains 2 tables and 4 figures.)