Neural dynamics of effort‐modulated reward processing

Previous studies have established that effort can either decrease reward value as a cost or increase reward value as an augmenter, which is referred to as the effort paradox. The present event‐related potential study investigated the neural dynamics underlying the modulation of reward processing by effort expenditure. Thirty‐two participants completed a modified monetary incentive delay task in a high‐effort context and a low‐effort context to earn monetary rewards while their EEG was recorded during effort anticipation, effort execution, and effort completion, respectively. Results revealed the multiphase nature of the effort–reward relationship, which unfolds over time. During effort anticipation, effort discounts reward value as reflected by a reduced contingent negative variation for high‐ versus low‐effort trials. During effort exertion, the target‐P3 reward effect was accrued by effort expenditure. Finally, effort also provides its own value following effort completion, as revealed by an enhanced stimulus‐preceding negativity for high‐effort relative to low‐effort trials. These findings provide new insights into the relationship between effort expenditure and reward processing and are helpful to mitigate the effort paradox. Our findings add a new perspective on the effort–reward relationship in terms of neural dynamics. We provide evidence that effort discounts reward value during effort anticipation but enhances reward value during effort exertion and provides its own value following effort completion. Our results demonstrate a multiphase model of the effort paradox.