Effort expenditure not only discounts reward value prospectively but also accrues reward value retrospectively. To decompose the effort paradox in reward processing, the current event-related potential study investigated the neural dynamics underlying effects of effort expenditure on subsequent reward processing. Participants exerted one of two levels of effort to obtain an opportunity of winning a high or low amount of monetary reward, and we focused on electrophysiological activity during the anticipatory and consummatory phases of reward processing. During the anticipatory phase, the stimulus-preceding negativity was enhanced when potential high rewards were anticipated, but this reward effect disappeared following high-effort expenditure. During the consummatory phase, feedback-related ERPs were increased for high relative to low rewards, and this reward effect was enlarged following effort expenditure during the early stage (200-300 ms) as indexed by the reward positivity but not the late stage (400-600 ms) as indexed by the P3. Our findings provide a strong support for the psychological contrast theory and indicate that time matters in decomposing the effort paradox for reward processing such that effort expenditure reduces reward sensitivity during the anticipatory phase but enhances reward sensitivity during the consummatory phase.

中文翻译：

---

分解奖励处理中的努力悖论：时间很重要。

努力支出不仅可以预期地折现奖励价值，而且可以追溯性地累积奖励价值。为了分解奖励过程中的努力悖论，当前与事件相关的潜在研究调查了努力支出对后续奖励过程的潜在影响的神经动力学。参与者付出了两种努力中的一种来获得赢得高额或低额金钱奖励的机会，并且我们专注于奖励处理的预期阶段和完善阶段的电生理活动。在预期阶段，当预期潜在的高回报时，刺激之前的消极性会增强，但这种努力的效果会随着高投入而消失。在完善阶段，与反馈相关的ERP相对于低报酬而言有所提高，奖励效果随着奖励积极性所指示的早期（200-300毫秒）的努力支出而扩大，但不如P3所指示的晚期（400-600毫秒）那么大。我们的发现为心理对比理论提供了有力的支持，并指出时间在分解奖励处理的努力悖论时很重要，因此努力支出在预期阶段降低了奖励敏感性，但在完善阶段提高了奖励敏感性。