Freedom through understanding: instructed knowledge shapes voluntary action choices

The capacity for voluntary action is a distinctive feature of human minds. However, experimental studies of volition struggled to capture defining features of human voluntariness. Here we developed a competitive game which incentivised participants to innovate their action choices to find the right time to avoid a collision with an opponent who predicted the timing of the participant’s action choice. One group of participants received explicit information about the competitor’s action-selection rules, while a second group had no information about the competitor. Both groups showed increased behavioural stochasticity when adapting to a competitor who punished participant’s choice biases. However, the group who had no explicit information generated their action choices in a way that avoided the action that the competitor was likely to take. In contrast, the group who explicitly knew the competitor’s action-selection rules avoided the same action they took in preceding trials so that the competitor could not easily exploit the participant’s behavioural patterns. These findings suggest that people can develop beliefs about other agents in the social environment within which they work, and can adapt voluntary action choices accordingly. However, explicit explanations about the other agent facilitate model-based planning in the voluntary generation of novel action patterns.