A procedure has been developed to measure the repeated acquisition of serial position sequences and to study the effects of drugs and toxic chemicals on the behavior generated by the procedure. Thus far experiments using the procedure have shown: (1) Performance schedules generate lower error rates than corresponding acquisition schedules: (2) Addition of a reset contingency further decreases errors under both performance and acquisition schedules: (3) Chained acquisition and performance schedules generate lower error rates than corresponding tandem acquisition and performance schedules: (4) Chained acquisition and performance schedules produce behavior that usually is more sensitive to drugs than corresponding tandem acquisition and performance schedules: (5) Acquisition schedules produce behavior that usually is more sensitive to drugs than corresponding performance schedules: and (6) Lead is an exception in that it produced clearer effects under a chained performance schedule with a reset contingency than under a corresponding acquisition schedule. The greater sensitivity to drug effects of behavior under acquisition schedules than behavior under performance schedules and of behavior under chained schedules may be a function of the baseline error rates, rather than the behavioral processes of acquisition, performance, and stimulus control.