| Abstract: | Pigeons and rats were exposed to multiple schedules with different schedules of electric shock superimposed on identical schedules of food reinforcement during each of two components. During one component, (adjusting-intensity) the intensity of electric shock depended on responding. Each response increased the intensity while intensity decreased between responses. During the other component (constant-intensity) the intensity was fixed at the value at which it had been adjusted at the end of the immediately preceeding adjusting-intensity component. In one experiment, shock was continuous during both components. In another experiment, instead of continuous shock, a brief pulse was delivered immediately after each response. During the adjusting-intensity component of both experiments, pigeons and rats responded at a rate just sufficient to keep the shock constant (critical rate). During the constant-intensity component, responding depended on whether shock was delivered continuously or in pulses. When shock was continuous, response rate during the constant-intensity component was higher than the critical rate. When shock was pulsed, response rate during the constant-intensity component was equal to the critical rate. |
