Is discounting impulsive?. Evidence from temporal and probability discounting in gambling and non-gambling college students.

Discounting tasks were used to evaluate whether gambling and non-gambling college students (categorized based on their scores on the South Oaks Gambling Screen) differed in the degree to which they discounted delayed and probabilistic rewards. Hyperbola-like functions provided equally good descriptions of discounting in both groups. Both groups discounted large delayed amounts less steeply than small delayed amounts, whereas both groups discounted large probabilistic amounts more steeply than small probabilistic amounts. Gamblers discounted probabilistic rewards less steeply than non-gamblers, suggesting that gamblers are impulsive in the sense that they are less affected by risk than non-gamblers. However, gamblers did not discount delayed rewards more steeply than non-gamblers. The results argue against the view that impulsivity is a general trait that includes both an inability to delay gratification and a tendency to take risks.