Effort choices are sensitive to prior learning

Motivated behaviour relies on both learning and effort-based decision-making, yet these processes are often studied in isolation. We developed a novel paradigm combining probabilistic associative learning with effortful choices to better model real-world goal-directed behaviour. Participants (n=252) successfully learned stimulus-outcome associations, with marked individual differences in learning fidelity. Reward and loss stimuli differed in their ability to motivate effort, revealing a valence-specific asymmetry. Crucially, trial-by-trial effort choices were better predicted by participants’ subjective beliefs than by objective probabilities – demonstrating that the willingness to exert effort is sensitive to prior learning. Notably, higher levels of anhedonia were associated with reduced willingness to engage in effortful action and a weaker alignment between learned value and action, suggesting a disruption in the integration of belief and motivation. These findings offer new insight into how value learning and effort expenditure interact, with implications for understanding motivational difficulties in psychiatric conditions.