Remember the future: working memory training decreases delay discounting among stimulant addicts.

BACKGROUND Excessive discounting of future rewards has been observed in a variety of disorders and has been linked both to valuation of the past and to memory of past events. METHODS To explore the functionality of discounting and memory, we examined whether training of working memory would result in less discounting of future rewards. In this study, 27 adults in treatment for stimulant use were randomly assigned to receive either working memory training or control training according to a yoked experimental design. Measures of delay discounting and several other cognitive behaviors were assessed pre- and posttraining. RESULTS Rates of discounting of delayed rewards were significantly reduced among those who received memory training but were unchanged among those who received control training; other cognitive assessments were not affected by memory training. Discount rates were positively correlated with memory training performance measures. CONCLUSIONS To our knowledge, this is the first study demonstrating that neurocognitive training on working memory decreases delay discounting. These results offer further evidence of a functional relationship between delay discounting and working memory.