A pigeon's rate of key pecking during the presentation of one stimulus was modified by changing only the schedule of reinforcement associated with a different stimulus. Typically, the rate of responding increases in the component of a multiple schedule whose schedule is maintained as reinforcement when the schedule in the other component is changed from reinforcement to extinction. The present experiments show that, in addition, a time out (no lights in the experimental chamber and no reinforcements), which immediately produces a near-zero rate of responding, also results in an increase in the rate of responding in the other component. Both extinction and time out produce a lower rate of responding and fewer reinforcements than does a Vl schedule. In order to separate the effects of not responding from the effects of no reinforcement, food was presented when no responses occurred for 50 seconds during extinction or time out. Reinforcement for not responding, concurrent with extinction or time out in one component, produced very low rates of responding but maintained a high frequency of food presentations. Under these conditions, the increase in the rate of responding on the Vl schedule in the other component (behavioral contrast) was eliminated.