Many studies have demonstrated differential resistance to change in the context of negative behavioral contrast. That is, as a result of introducing a disruptor, response rates decrease to a greater extent when the maintaining reinforcement schedule is leaner. Resistance to change also applies to positive contrast, in that increases in response rate are greater in leaner schedules. The negative contrast effects seen in studies of intrinsically motivated behavior reflect an increase in resistance to change as a result of adding extrinsic reinforcers.