Learning when to wait and when to act.

Choosing how long to wait in order to optimize reward is a complex decision. We embedded these decisions within a video-game environment in which the amount of reward smoothly increased the longer one waited. The availability of external cues varied in order to determine how they affected the decision to wait to achieve the goal of maximizing the reward rate. As a group, people were most optimal when they could directly observe the growth in reward, and this information overshadowed a static color cue that did not require extended observation. These results were considered within the context of improving the choice between acting versus waiting in order to maximize reward rates.