A Conjunctive Schedule of Reinforcement¹

In a fixed-interval schedule, the event that programs the reinforcement of a response is the passage of a specified period of time without reinforcement. Rein- forcement on a fixed-ratio schedule depends upon the occurrence of some fixed number of unreinforced responses.4 The conjunctive fixed-interval, fixed-ratio schedule combines these two schedules by arranging that a response is reinforced only after the passage of the time period and the emission of some minimal number of unreinforced responses.