Depression effect as a function of retention interval before and after shift in reward magnitude.

Abstract

70 rats were employed in a runway experiment to study the "depression effect" as a function of a retention interval interposed either before or after the shift in reward magnitude. 1/2 of the Ss were initially trained with a high reward and 1/2 with a low reward; all were tested under the low reward magnitude. After a 2-mol retention interval the depression effect failed to develop, regardless of whether the interval was interposed before or after the shift. These results suggest that rats forget the reward magnitudes previously experienced and may also forget their own reaction to the downward shift.