A Pavlovian, conditioned-reinforcement approach to reducing impulsive choice

Persistent impulsive choice, preference for a smaller-sooner over a larger-later reward, is associated with consequential life outcomes. Procedures that reduce nonhuman impulsive choice often have long training durations that reduce their translational utility. This experiment sought to alter the behavioral function of the stimulus rats encountered during the delay to the larger-later reward. That putatively aversive delay-signaling stimulus was given an appetitive function through Pavlovian conditioning. Forty Long-Evans rats (20 male) were randomly assigned to undergo Pavlovian training (lever-CS precedes food delivery by 8 s), and the other half underwent unpaired training (CS uncorrelated with food). During the test of impulsive choice that followed, choosing the larger-later reward produced 10-s access to the CS during the 20-s delay to that reward. Pavlovian training significantly increased larger-later reward choice relative to rats in the Unpaired group. The large effect size and ease of training are discussed in the context of potential translational research.