Resource-rational adaptations to different intertemporal choice environments affect evidence accumulation and encoding-related processes

Biological organisms must adaptively allocate their limited cognitive resources to maximize performance in different environments. Recent work has shown that resource-rational adaptation to the reward statistics of an environment can influence human decision making. Here, we examine resource-rational adaptation during binary intertemporal decisions within contexts that contain different levels of volatility in delayed reward magnitudes, while jointly considering both choices and decision times. We found that the choice sensitivity along the relevant decision dimension was higher in the low reward-volatility condition. This effect was accompanied by higher non-decision times, which are thought to be partially determined by initial encoding of the decision options. We also tested whether adaptation during the binary choice phase would carry over to a second type of intertemporal decision task, in which participants expressed their willingness-to-pay (WTP) to forgo having to wait to receive an offered amount. We found that participants reported their WTP to forgo delays faster following the low reward-volatility binary choice context. Taken together, our results indicate that resource-rational adaptations to reward volatility contexts affect stimulus encoding and evidence accumulation processes, and that these adaptations show near-transfer across decision formats.