Effects of effort training on effort-based impulsive choice.

Because impulsive decision-making is correlated with many maladaptive tendencies, researchers have increasingly studied methods for reducing impulsive choice. These efforts have primarily focused on increasing choices of larger, more-delayed rewards. A second type of impulsive choice is selecting a smaller, less-effortful reward over a larger, more-effortful one. Little nonhuman research has examined experimental methods for reducing effort-based impulsive choice. Within the realm of delay-based impulsive choice, extended exposure to reinforcer delays has proven effective in reducing impulsive choices in rats. The current study took a similar tack by evaluating if reductions in effort-based impulsive choice could be achieved by providing rats with extended exposure to high-effort training, that is, reinforcement contingencies requiring a large number of responses. Male rats were randomly assigned to either a high-effort training (fixed-ratio 50) or low-effort training (fixed-ratio 1) group. Following training, both groups completed a test of effort-based impulsive choice. High-effort training produced a temporary reduction in effort-based impulsive choice. In the same test phase, groups also differed in response run durations (shorter following high-effort training), with larger differences in the initial sessions, which may have contributed to the short-term effect of high-effort training in effort-based impulsive choice.