Volition and Conflict: the role of action selection in the sense of agency

Voluntary action lies at the heart of human nature. In daily life, most people feel that they cause and control their own movements, through which, they can influence the external world. This feeling of causality and control has been referred to as the sense of agency. During the last two decades, the sense of agency has become an increasingly prominent research topic. Nevertheless, a thorough understanding of the sense of agency is still lacking. This thesis explores the cognitive mechanisms underlying the sense of agency. Specifically, the study focuses on how the agency experiences emerge and change during the action selection processes. By measuring the explicit judgment of agency in the stimulus-driven and self-controlled action selections, the study consolidates that the action selection fluency is a significant metacognitive factor contributing to the sense of agency, whereas action conflicts undermine the sense of agency. Besides, the action selection conflict doesn’t affect the time perception of the actions and outcomes, which is an important indicator of the implicit agency. The results suggest different aspects of agency and dissociation between the explicit and the implicit measures of agency. Furthermore, we find that the sense of agency is modulated by the previous action selection. The previous conflict reduces the subsequent action selection fluency effect on the agency. Finally, the latter experiments show that temporal delays increase the performance and affect the action selection fluency effect on the sense of agency. Overall, this thesis has proposed that a durative dynamic system in human brain contributes to the voluntary action selections and the agency experiences associated with it.