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What is volition? Characterising voluntary action using subjective, behavioural, and neural markers

par Pech, Guillaume
Président du jury Destrebecqz, Arnaud
Promoteur Cleeremans, Axel
Co-Promoteur Maoz, Uri
Publication Non publié, 2026-03-13

Thèse de doctorat

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Résumé :

Our lives matter not simply because we are, but because we do. Throughout our entire existence, we are not passively reacting to our environment but acting upon it. As a result of these acts, we are held responsible for what we cause. Most societies, and the educational and justice systems that structure them, rely on the idea that we can perform voluntary actions and that we can be praised or blamed for these actions. Yet despite the central role of this phenomenon, little is known about what voluntary action actually is.This thesis examines four proposed characteristics of voluntary action: selfgeneratedness, control, reason-based, and subjectively experienced. The chapters build directly on this framework. Chapter 2 examines what it means for an action to be self-generated, aiming to clarify both the conceptual definition of self-generation and its associated markers. Chapter 3 investigates how self-generated action interacts with control over action consequences, deepening our understanding of the relationship between intentional initiation and predictive control. Chapter 4 turns to goaldirectedness, asking how reasons shape volition and whether effort can serve as an index of volitional engagement, thereby refining the notion of reason-based action. Finally, Chapter 5 examines the role of conscious experience, addressing whether phenomenal agency and conscious access to motivational cues play a functional role in motivating and guiding action.Behaviourally, the thesis relies in particular on Temporal Binding, the compression of the perceived time interval between an action and its consequence. Temporal binding is used as an implicit proxy of the sense of agency, capturing how agents experience the temporal coupling between cause and effect when an outcome is attributed to one’s own action. Neurally, the thesis investigates the Readiness Potential (RP), the slow build-up of preparatory EEG activity that precedes self-initiated movement.Across chapters, several contributions emerge. First, the distinction between selfgenerated and cued-generated action can be made more precise: choosing which action to perform, beyond merely executing it, appears to matter for the subjective experience of agency, and it does so in ways not reducible to difficulty alone. Second, self-generatedness and control over consequences interact. We generate actions to achieve effects, and when outcomes become unpredictable, action preparation and phenomenology change. Crucially, this weakening is most evident when the goal of acting concerns the outcome itself, rather than merely following an instruction, suggesting that the reason for acting shapes preparation. Third, the thesis treats goaldirectedness and clarified what “arbitrary” decisions can mean. By manipulating relevance, we show that reasons can strengthen multiple markers of volition, and we introduce effort as a promising additional measure of volitional engagement. This matters beyond theory. Volition is clinically relevant for disorders involving initiation, inhibition, and agency; and it is socially relevant because responsibility presupposes capacities for intention formation, monitoring, and control. Even when the ability to move a finger “when I want” seems trivial, it anchors our notions of wellbeing, education, and legal accountability. For these reasons, a science of volition, however difficult, remains worth pursuing.