Schedules of Reinforcement Schedule of Reinforcement Fixed-ratio (FR) Definition and Examples Reinforcement occurs after a fixed number of responses, e.g., piecework in a factory Variable-ratio Reinforcement occurs after an average number of responses, (VR) which varies from trial to trial, e.g., slot machines Reinforcement occurs for the first Fixed-interval response emitted after a preset time (FI) has elapsed, e.g., scheduled exams Variable-interval Reinforcement occurs for the first response emitted after an average (VI) amount of time has elapsed, but the interval varies from trial to trial, e.g., study habits of students when instructor gives pop quizzes. Effects Produces a high rate of responses that follows a burst-pause-burst pattern. Produces a high, steady rate of response. Responses increase as the time for the next reinforcer nears. Produces a moderate, steady rate of response. c. I -- 0! £0