Research reportI endeavor to make it: Effort increases valuation of subsequent monetary reward

•Effort, in general, could enhance subjective valuation toward gain-loss outcome.•FRN and P300 represent modulated effect of varied efforts during outcome evaluation.•P300 also exhibits the valence effect of feedback at the late stage of evaluation.

Although it is commonly accepted that the amount of effort we put into accomplishing a task would exert an influence on subsequent reward processing and outcome evaluation, whether effort is incorporated as a cost or it would increase the valuation of concomitant reward is still under debate. In this study, EEGs were recorded while subjects performed calculation tasks that required different amount of effort, correct responses of which were followed by either no reward or fixed compensation. Results showed that high effort induced larger differentiated FRN responses to the reward and non-reward discrepancy across two experimental conditions. Furthermore, P300 manifested valence effect during reward feedback, with more positive amplitudes for reward than for non-reward only in the high effort condition. These results suggest that effort might increase subjective evaluation toward subsequent reward.