Effects of Repeated VI Reinforcement and Extinction upon Operant Behavior

Abstract

Four pigeons trained on a 1-min. VI schedule were reinforced, extinguished, and reconditioned under each of two stimulus conditions for 20 daily sessions. The average rate in extinction decreased significantly as a function of the number of extinctions. A concurrent increase in rate occurred during VI reinforcement periods. Extinction occurred more rapidly as it was repeated. Assuming an exponential decay in rate of responding during extinction, the effects of repetition upon the parameters of fitted curves was examined. The decay constant (ratio of deceleration to rate) increased linearly as a function of the number of extinctions, while the log initial rate decreased linearly. These changes in extinction parameters were in the same direction as previously obtained in an experiment involving another species and procedure, but which did not permit determination of the form of relations between extinction parameters and the number of extinctions. The empirical grounds for the exponential decay assumption are discussed in connection with the effects of the principal independent variables influencing the course of operant extinction.