Effects of probability and magnitude of reinforcement in a temporal schedule with different response requirements

Abstract

Four experimentally naive rats were used to assess the effects of decreasing reinforcement probability under two reinforcement magnitudes. A T Schedule with two response requirements was instrumented. The two response requirements, varied withinsession, were one or five responses in to reinforced with a single or a double drop of water, under signalled and unsignaled conditions. Reinforcement probability was reduced in succesive phases with values of 1.0, 0.5, 0.1 and 0.0, reversing to the first value in the last phase. Response rate was a monotonic decreasing function of decreases in reinforcement probability, regardless of response requirement or reinforcement magnitude. No differential effects of signaled vs unsignaled tD cycles were found. Additionally, the local response rates were higher under the five response requirement than under the one response requirement. We discuss the generality of the effects of reinforcement probability and analize the role of imposed ratio requirements