Freedom through understanding: instructed knowledge shapes voluntary action choices

Abstract The capacity for voluntary action is a distinctive feature of human minds. However, experimental studies of volition struggled to capture the defining features of human voluntariness. Here we developed a competitive game that incentivized 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 was explicitly instructed that the competitor would monitor the participant’s action choices, while a second group had no information about the competitor. Both groups showed increased behavioural stochasticity when adapting to a competitor who punished participants’ choice biases. However, the group that had no explicit information avoided the action that the competitor was likely to take. In contrast, the group that 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 voluntarily develop beliefs about how the other agent thinks the participant’s behaviour and can adapt voluntary action choices accordingly. However, developing this socialized aspect of volition requires instructed knowledge about the other agent—it does not arise spontaneously through trial-and-error alone.