Lead supervisor:
Prof Guillaume Thierry 
Other supervisor(s):
- Dr Samuel Jones
Start date: October 2025 (Full time)
Award: General
Subject Pathway:
Psychology
Thematic Cluster:
Language, Learning and Behaviour Cluster
Resetting Libet’s Clock: Measuring the timing of conscious awareness of a decision to act using machine learning analysis of EEG data.
Do we have free will?
What do we mean by free will?
Are we the conscious authors of our actions, or deterministic automata in which consciousness is an epiphenomenon, and free will merely a construct we have a social need for?
Does any of this matter? After all, if everything is pre-determined why worry about anything?
These issues have been debated for millennia, and are fundamental to how we view the actions of others, how sympathetically we may treat them or assign punishments to transgressors.
Forty years ago, Benjamin Libet (1983) compared the relative timings of awareness of a decision to act, with EEG signals associated with preparation to act, and thus began the field of volitional neuroscience. His findings have been debated, criticised, ridiculed, dismissed (Neafsey, 2021)… and replicated (Braun et al. 2021) in environments ranging from the lab to bungee jump platforms. Forty years and over 8,000 citations later the implications of those findings are still being debated.
Libet compared the timing of an ERP in measured EEG recordings (specifically the bereitschaftspotential (BP) or ‘readiness potential’) with participants' reported time of conscious awareness of a decision to move. On average, the BP preceded that awareness by around 500mS. One interpretation being that the brain had decided before the individual was aware of it, thereby raising the question of how could the decision to move have been made consciously?
I have a background in Physics and Engineering, and having taught control systems design and non-linear systems analysis in parallel with my interest in volition for a decade. I’m bringing the two together: using signal processing and machine learning analysis techniques unavailable to Libet, to refine and provide subtler and more objective measurements of the non-conscious neural activity that leads to a conscious outcome - be it a thought, decision or physical action.
Why am I doing all this? Well... I’m not sure I have any choice to do otherwise.
Research Impact
Libet's experiments have been criticised for their design, interpretation and ecological validity. While the outcome of any decision could be said to have an infinite regression of antecedent causes, those last few milliseconds are an important link in the causal chain.
My research will address three areas of criticism:
- Improved experimental design
- Attempting to identify a neural correlate of the moment of awareness, removing the need for subjective self-report.
- Application of the method to different categories of decision, of increasing complexity and consequence
Bibliography
Braun, M.N., Wessler, J. and Friese, M. (2021). A meta-analysis of Libet-style experiments. Neuroscience & Biobehavioral Reviews, 128, pp.182-198.
Libet, B., Gleason, C.A., Wright, E.W. and Pearl, D.K. (1983). Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential) the unconscious initiation of a freely voluntary act. Brain, 106(3), pp.623-642.
Neafsey, E.J. ( 2021). Conscious intention and human action: Review of the rise and fall of the readiness potential and Libet’s clock. Consciousness and Cognition, 94, p.103171.
Biography
On a personal note, I have been studying this topic for over twelve years. Research in this field can provoke strong reactions. In my experience this has ranged from indifference to outright hostility. It challenges the 'notion of self' and the implications cross over into philosophical, societal and legal domains. Whether or not we have free will, belief in free will has been shown to influence attitudes and behaviour. Dan Dennett cautions researchers in the field to consider the "environmental impact" of their work, drawing a colourful analogy with someone feeling the need to tell Disney's Dumbo that his magic feather isn't magic. Indeed, some would argue the free will issue goes to the very core of what it means to be human. But in the words of Joshua Greene, "...neuroscience changes nothing and everything." Whatever we find out about free will, I would argue it changes nothing about the beauty of a sunset, the smell of bread baking, the feeling of enjoying time with friends, and while absence of free will would not remove the need for social cohesion, it should inform how we view and label the actions of others, how we balance retributive vs restorative justice and the compassion we show to our fellow humans who, but for a roll of the complex yet deterministic cosmic dice, we might have been.
When I'm not contemplating such weighty issues: I enjoy exploring and photographing wild and rugged places, I study Japanese sword arts and I occasionally dress as a pirate for reasons I'm never entirely sure about.