title: The combined effects of delay and probability in discounting.
abstract: Human discounting studies have frequently observed hyperbolic discounting of rewards that are delayed or probabilistic. However, no studies have systematically combined delay and probability in a single discounting procedure. Indifference points of hypothetical money rewards that are both delayed and probabilistic were determined. Probabilities were converted into comparable delays according to the h/k constant of proportionality determined by , and discounting rates were calculated. These data provided a very good fit to the hyperbolic model of discounting, suggesting that delay and probability can be combined into a single metric in studies of discounting. The inclusion of a magnitude condition found the Magnitude Effect commonly found in studies of temporal discounting. A temporal resolution of uncertainty condition found no effect. The present paper offers a novel statistical method, within an established framework, for the analysis of data from studies of discounting that combine delay and probability.
authors.affiliation: Department of Psychiatry, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA. ryi@uams.edu
authors.forename: Richard
authors.initials: R
authors.lastname: Yi
authors.forename: Xochitl
authors.initials: X
authors.lastname: de la Piedad
authors.forename: Warren K
authors.initials: WK
authors.lastname: Bickel
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D002755:Choice Behavior; D005260:Female; D006801:Humans; D007175:Impulsive Behavior; D008297:Male; D018803:Models, Economic; D009042:Motivation; D011337:Probability Learning; D011340:Problem Solving; D012201:Reward; D013997:Time Factors; D014040:Token Economy