Effort reinforces learning
Humans routinely learn the value of actions by assessing their outcomes. Actions also require effort, and increasing evidence suggests that effort and learning share common neurophysiological substrates. Here, we asked whether effort could modulate teaching signals in a reinforcement learning task. Individuals (N=140) registered their choices by exerting predefined levels of physical force. Our key finding was that effort increased the subjective value of an outcome, regardless of whether that outcome was positive or negative. Moreover, across participants, the extent to which effort reinforced learning correlated with effort discounting, suggesting that effort has a greater effect on learning in those who are more averse to investing it. By integrating models of reinforcement learning with neuroeconomic frameworks of value-based decision-making, we show that learning is shaped by both rewards and the effort required to obtain them, thus revealing how effort and learning operate within a common computational framework.