EEG, fMRI and brain stimulation evidence for epiphenomenal conscious will

Abstract

Event Abstract Back to Event EEG, fMRI and brain stimulation evidence for epiphenomenal conscious will Magnus Jandel1* and Hans Liljenstrom2 1 Swedish Defence Research Agency, Biology Dep, Sweden 2 SLU, Division of Biometry and Systems Analysis, Sweden Aim: Scant evidence from neuroscience (1-2) is used to support the philosophical position that conscious will is not causally related to the willed action, i.e. epiphenomenal. We want to dispose of the superfluous philosophical ballast, clarify what the data really can tell us and point to a way forward for future empirical work. Methods: We review the present EEG, fMRI and brain stimulation evidence for epiphenomenal conscious will considering alternative interpretations and suggestions for refined experiments. Results: Systematic effects of pre-planning on the EEG readiness potential is investigated and found to explain much of the timing behaviour that traditionally has been taken as evidence for epiphenomenal conscious will. Soon et al. (2) investigated timing correlations between conscious will and brain events measured by MRI. The fMRI maps were fed to an algorithm that managed to predict the action with at most 60% accuracy, based on fMRI data that was captured about ten seconds before the willed action. We find that this correlation could alternatively be understood as an effect of occasional unreported pre-planning, a correlation between the memory of the previous action and the next action, or a weak correlation between unconscious precursor processes and a causally connected conscious will. Desmurget et al. (1) found that stimulation of parietal areas sometimes triggers conscious will and an illusory awareness of movement. Comparing with similar experiments we find many cases where brain stimulation triggers hallucinations. The pooled brain stimulation data cannot be taken as evidence for epiphenomenal conscious will in wakeful subjects. Conclusion: We find little experimental support for the hypothesis of epiphenomenal conscious will. Much of the recent literature on what neuroscience can say about conscious will draws unwarranted philosophical conclusions from inadequate data. This is unfortunate since beliefs about the nature of conscious will is known to impact on behaviour (3). Acknowledgments: This work was supported by the European Commission, the Swedish Foundation for Strategic Research and by the Swedish Research Council.