The present study contributes an apparatus and research paradigm useful in generating human performances sensitive to concurrent schedules of reinforcement. Five participants produced performances observed to be under temporal and ratio control of concurrent fixed interval-fixed ratio schedules. Two aspects of interaction between FI and FR schedules were distinguishable in the data. First, interaction between two schedules was observed in that changes in the value of one schedule affected behavior reinforced on another schedule. Second, switching from one pattern to the other functioned as an operant unit, showing stability during schedule maintenance conditions and sensitivity to extinction. These effects are discussed in the context of current views on behavior under concurrent schedules of reinforcement, and some implications for the conceptualization, measurement, analysis, and treatment of complex behavior are presented
