Effects of Fixed-Interval and Fixed-Ratio Schedules of Token Reinforcement on Exercise with Obese and Nonobese Boys

Abstract

The effects of fixed-interval (FI) and fixed-ratio (FR) schedules of reinforcement for pedaling on a stationary exercise bicycle were examined. Two obese and two nonobese boys were individually tested 5 times weekly for 10 weeks. An ABCB single-case research design was used where A = Baseline, B = FI 1 min, and C = FR × (a schedule matched in reinforcement frequency to that obtained by each subject under FI). The results indicated that although the introduction of FI 1 min produced increases of over 300% above the end of baseline in exercise duration for all subjects; the obese subjects’ response rate rapidly declined whereas the nonobese boys’ response rate increased. Implementation of the FR schedule produced dramatic increases in the two obese and one nonobese subjects’ response rates; high stable responding was maintained by the other nonobese subject. Response rates decreased for all subjects during the return to FI phase. Increased duration of exercising was maintained during all contingency phases. Cumulative records demonstrated high stable responding with no discernible pausing for nonobese boys. In contrast pausing and accelerating were evident in the obese boys’ records with the development of transitory scalloping for one obese subject. Postexperiment physical fitness tests indicated a reduction in percentage of body fat for the two obese and one nonobese subjects.