Effects of Consecutive Shifts of Magnitude of Reward on Runway Performance

Abstract

The purpose of this study was to reexamine Hull's Theorem 30 and Pereboom's modification of that theorem. Following 42 runway acquisition trials with consecutively (upward or downward) shifted reward magnitudes, all groups of rats were extinguished and then retrained with a medium reward magnitude. The results of the original acquisition trials seem to satisfy Hull's prediction, but during reacquisition all experimental groups attained asymptotic performance levels higher than that obtained for the control group trained with a low magnitude of reward during original acquisition. This evidence clearly suggests that neither Hull's not Pereboom's theorem is consistent with the empirical evidence.