Cigarette smokers discount past and future rewards symmetrically and more than controls: is discounting a measure of impulsivity?

A considerable body of evidence indicates that consideration of the future and past are related. Future discounting studies indicate that cigarette smokers discount future outcomes more than non-smokers. The purpose of the present study was to determine if a similar profile of results could be obtained with a novel procedure evaluating the discounting of past outcomes, providing further support for future/past symmetry. Thirty cigarette smokers and 29 non-smokers participated in a computerized assessment of discounting of hypothetical future and past outcomes. Symmetry was supported, with a similar profile of results in future and past discounting procedures. These included: hyperbolic discounting, greater discounting of small-magnitude outcomes than large-magnitude outcomes, and greater discounting by cigarette smokers relative to non-smokers.