Hyperbolic temporal discounting in social drinkers and problem drinkers.

Two studies compared participants, distinguished by their typical alcohol consumption, on the degree to which they discounted the value of delayed, hypothetical amounts of money. Heavy social drinkers in Study 1 and problem drinkers in Study 2 both showed greater temporal discounting than light social drinkers; this difference was stronger in Study 2. Both studies found that a hyperbolic function described temporal discounting more accurately than an exponential function. These results are consistent with extending behavioral theories of intertemporal choice to characterize the determinants of alcohol consumption. The discounting differences also are consistent with more general behavioral economic and economic theories of addiction, although the hyperbolic functional form is inconsistent with the exponential discounting function in economic theory. The drinker groups also differed on impulsiveness and time orientation questionnaires, with light drinkers being less impulsive and more future oriented; however, these measures were not strongly correlated with the measure of temporal discounting.