Delay discounting task
Participants completed a computerized delay discounting task as described previously (For each delay interval, a “switch point” was defined as the midpoint between the lowest immediate reward selected by the subject and the next lowest immediate reward in the sequence (i.e., the value of immediate reward at which the subject began consistently to select the standard 1,000 SEK delayed reward), and was determined by fitting choice data to a square-wave function. We chose this fitting procedure because it was relatively robust and stood up well to occasional inconsistencies in participants’ choice behavior. The 7 indifference points were then fitted to a hyperbolic discounting function 