Try and try again: Post-error boost of an implicit measure of agency.

The sense of agency refers to the feeling that we control our actions and, through them, effects in the outside world. Reinforcement learning provides an important theoretical framework for understanding why people choose to make particular actions. Few previous studies have considered how reinforcement and learning might influence the subjective experience of agency over actions and outcomes. In two experiments, participants chose between two action alternatives, which differed in reward probability. Occasional reversals of action-reward mapping required participants to monitor outcomes and adjust action selection processing accordingly. We measured shifts in the perceived times of actions and subsequent outcomes ('intentional binding') as an implicit proxy for sense of agency. In the first experiment, negative outcomes showed stronger binding towards the preceding action, compared to positive outcomes. Furthermore, negative outcomes were followed by increased binding of actions towards their outcome on the following trial. Experiment 2 replicated this post-error boost in action binding and showed that it only occurred when people could learn from their errors to improve action choices. We modelled the post-error boost using an established quantitative model of reinforcement learning. The post-error boost in action binding correlated positively with participants' tendency to learn more from negative outcomes than from positive outcomes. Our results suggest a novel relation between sense of agency and reinforcement learning, in which sense of agency is increased when negative outcomes trigger adaptive changes in subsequent action selection processing.