One member of each pair of 52 undergraduates, referred to as a learner, was trained BC conditional discriminations, with B stimuli as the samples and C stimuli as the correct comparisons. Responses of the learner were either reinforced or punished by another member of each pair, an instructor, who had previously mastered AC conditional…

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…