Review of “Free Will and NeuroScience” Talk
Robert Nola on Philosophy, Free will, and Neuroscience.
Review and Questions for reflection.
Nola began by first asking “What is free to be predicated of?” Do we want out actions to be free, or our decisions, or both? We can have free actions by being able to act as we chose (Nola calls this “first level freedom”), but there is a further question as to whether we can want and desire as we choose. We may want a beer because we are an alcoholic, but we might not want to want a beer. Nola suggested that a second level of freedom – freedom of choices and desires (or what some might call “the will”) – could perhaps be attained by critical reflection on ones beliefs and desires. Of course, the obvious objection to this thought is that perhaps our beliefs and desires that lead us to question our beliefs and desires are not free either!
Nola then asks us to consider an experiment by Libet and Feinstein (1983). A subject is told to move their finger when they feel the urge to do so. They are also asked to take note of when they felt the urge. A 200 millisecond delay was found between the awareness of the urge and the movement itself, but, more interestingly, the EEG electrodes attached to the scalp of the subject registered a signal in the brain up to (approx) 500 milliseconds before the action! This signal is called the readiness potential, or “RP”. Our folk intuition is that we decide to act before our brain begins to prepare for the action, but this experiment seems to suggest that it is the other way around!
More recently, in BBC Horizon’s “The Secret You” (2009), Haynes (BCAN) took a scan of du Sautoy’s brain while he was asked to push one of two buttons as soon as he felt the urge. The neuro-imaging showed that certain regions in the brain become more active when du Sautoy will chose left, and others when he will chose right. Amazingly, this happens up to 8 seconds before du Sautoy consciously feels the urge and pushes the button!
So, if Haynes can predict the likelihood of du Sautoy pushing one button or the other, up to 8 seconds before he pushes it, is du Sautoy still performing a free action? Nola points out that he correctly predicted we’d all sit down when we came to his lecture, but we still seem to think that we freely chose to sat down. Du Sautoy asks if he is a hostage to his own brain, given that his brain decides before “he” does what action to perform (think Karl Pilkington, the onion, and the shopping list). Such a question however only makes sense if one takes a dualist position in which “you” are not the same thing as your brain.
In a similar experiment, Trevena and Miller (Otago 2009) played a tone to a subject who was to then decide to either push a button or not. They wanted to remove the “urge” feature of Libet’s experiment, and instead replace it with a command to decide. It is important to note that there is a distinction here between not deciding (as is the case before the tone is played), and deciding to not push the button. T&M found that the RP was present regardless of the subject’s decision to push or not push the button! This suggests that the rising RP does not correlate with an action. Does it perhaps instead correlate with a conscious decision? Or something as simple as the brain paying attention? It is not clear.
So does Trevena and Miller’s experiment undermine Libet’s? Are they testing the same thing but in a different way, or are they really testing something else? What is the causal relationship between the RP, the urge/decision to act, and the action itself? Does the RP cause the awareness of the decision or urge to act? Does the urge cause the action, or is it the RP that causes that action (except when it is vetoed)?
This brings us on to vetoing. In another experiment, subjects were asked to record when they felt the urge to move their finger, but to not act on that urge. It was found that there was an RP build up before the urge, but that the subject was successfully able to veto that brain command. This might suggest that while the unconscious mind “decides”, as it were, to perform the action, the conscious mind can freely(?) decide to veto the action. It has been suggested therefore that perhaps we are not free to chose to do something (our brain decides for us), but we are free to not do something once our unconscious has decided to do it – we have “free won’t”. But why should it matter that the action to be initiated by the conscious rather than the unconscious brain?
How should we define free will – do we want it to be the ability to do otherwise, that a causal chain is initiated in the conscious brain, or simply that we make a decision and can act on it? If my brain decides my actions, is that “me” deciding, or am I different from my brain? Should I mind if Nola, God, or anyone else for that matter, can predict (or even know) my future actions? Do I really want free will, or will “free won’t” suffice, and is there a difference?
For further reading/viewing:
Trevena and Miller (2002) Cortical movement preparation before and after a conscious decision to move. http://www.ncbi.nlm.nih.gov/pubmed/12191935?dopt=Abstract
Trevena and Miller (2009) Brain preparation before a voluntary action: Evidence against unconscious movement initiation. http://www.sciencedirect.com/science/article/pii/S1053810009001135
Psychology Today: Free Won’t: It May Be All That We Have (or Need). http://www.psychologytoday.com/blog/dont-delay/201106/free-wont-it-may-be-all-we-have-or-need
Stanford Encyclopaedia of Philosophy. Free Will. http://plato.stanford.edu/entries/freewill/
Wikipedia. Neuroscience and Free Will. http://en.wikipedia.org/wiki/Neuroscience_of_free_will
Karl Pilkington, the Onion, and the problem of Free Will.
Exert from BBC Horizon’s “The Secret You” (2009).