Temporal discounting refers to the reduction in the present subjective value of an outcome as a function of the temporal distance to that outcome. Though a number of mathematical models have been proposed to describe this time/value relationship, this search has largely excluded insights from the literature on memory decay. This study examines the utility of memory decay models by comparing the fits of four of these models to fits from established temporal discounting models using past and future temporal discounting data. These results (1) suggest that a single model describes valuation of both future and past outcomes, (2) indicate the exponential-power model, from memory decay literature, is statistically superior in fitting discounting data from both past and future outcomes, and (3) support the advancing perspective of the psychological interconnectedness of the future and past.