Thinking About the Libet Experiments (Again)

In a way, I hate thinking about how to properly interpret the famous Libet experiments on free will. For those who haven’t heard of them, the experiments are fairly simple. First, the brain is monitored in some way, usually with EEG. Then, the subject is asked to “consciously decide” to wag a finger. There are electrodes on the finger that can detect precisely when the finger moved. Moreover, when the subject “consciously decides” to wag their finger, they are instructed to look at a clock with a fast rotating hand. They are supposed to remember where the clock hand was when they felt like that had consciously decided to wag their finger.

What are the results? Well, the main thrust of the experiments is that Libet would see EEG activity that would reliably predict the movement of the finger before the subject reported even feeling to consciously decide to wag the finger. In other words, before the subject had “consciously decided”, some part of the brain was already active that reliably predicts finger-wagging. They can do this experiment now with more sophisticated techniques, and I think they can use brain activity some 10 seconds before the conscious decision to predict when the finger would wag. Pretty wild stuff, right?

Usually the Libet experiments are interpreted as showing that free will is an illusion and that consciousness is basically a mere side-effect of nonconscious processes. The idea is that the preconscious brain activity is in charge of really deciding to wag the finger. The “conscious decision” to wag the finger is a by-product or side-effect of this preconscious activity. So the idea then is that consciously deciding to do something and then feeling like it was that conscious decision which did the causal work is an illusion. Many theorists like Dan Wegner have thus concluded that consciousness is a retrospective illusion, with no causal efficacy.

Every time I think about the Libet experiments and all these interpretations about free will my head starts to hurt. Somehow it feels super fishy to me to conclude from the experiments that free will is an illusion. Of course, there is a sense in which the Libet experiments do prove the idea of free will to be false. If we thought that, whatever the will is, it can’t be physical or realized in the brain, then yes, the Libet experiments do seem to undermine this idea. Libet’s experiments conclusively show that the brain is a major player (if not the only player) in deciding what we do. If you are a physicalist like me, then this idea is pretty obvious. But I don’t think this immaterial spooky free will concept is really what’s at stake philosophically (although of course theists and dualists will disagree).

What’s at stake in my opinion is whether the Libet experiments call into question the conceptual distinction between voluntary and involuntary actions. Is there a fundamental difference between sneezing when I step into strong sunlight or on deciding to get married? Sneezing is usually understood as an automatic, involuntary reflex. Deciding to marry someone is a classic example of what we call a “voluntary action”. In my opinion, Libet’s experiments don’t call into question the basic legitimacy of this distinction. If even we lived in a perfectly deterministic world, it would still be right to distinguish in humans voluntary and involuntary behavior.

I think what the Libet experiments might show is that there is a neural realizer base for voluntary actions. No surprises there. But what about the idea that the “conscious decision” to wag a finger comes so late? It doesn’t seem to be quick enough to really call the shots for motor control. But I think this comes to the heart of the matter: is the “conscious decision” to wag a finger really the best example of when consciousness exercises control? Wagging a finger and deciding to get married are two radically different kinds of decisions. The first happens over the course of milliseconds, the second can happen over the course of months or years. In my own case, my decision to want to marry Katie was drawn out over a long time period. I really had to stop and reflect deeply about my future with Katie and whether I saw myself being happy with her 50 years in the future.

As a Jaynesian, I like to define consciousness to be a kind of introspective power, a power to reflect on the past, present, or future in ways that transcend the automatic and habitual tendencies of action shared by our animal cousins. Defined in this way, I’m not really sure the decision to wag a finger is really representative of the kind of action planning that consciousness is best suited for. Consciousness as I define it is not suited for millisecond control of finger motion. It’s more relevant for planning a wedding, or deciding to take that new job, or go on vacation. Consciousness as a action-controlling process is less a sensorimotor function as it is a narrotological function. Consciousness thinks in terms of stories. It is a long-term synthetic function. It operates on the longest time-scales in the brain. So finger wagging might just miss consciousness all together. So I’m not sure it’s best to conclude from the Libet experiments that consciousness is just an epiphenomena or mere side-effect that plays no causal role.

Don’t get me wrong though. There is a sense in which even the operations of a narratological consciousness are determinstic insofar as they are realized in brain tissue, and brain tissue of course follows physiological laws without deviation. So there is a sense in which even long-term, narratological conscious processes are “determined” by brain processes. If we could do a long-term Libet-style experiment on the causal precursors of my decision to get married, I’m sure we could find all sorts of precursors. But again, this is only surprising if we thought that the will must be immaterial and free-floating from physical processes. But the fact that consciousness is realized in the brain is no reason to think that sneezing is of the same action type as deciding to get married.  And of course there is whole host of intermediate action types between sneezing (a reflex, really) and getting married. There are certainly a lot of “higher” cognitive functions that are nonconscious, including powers of reasoning and perception. But I think it is crucial to the human sciences that we don’t collapse all these distinctions because of simple experiments like Libet’s. There is an important distinction to be made between voluntary and involuntary, between conscious and nonconscious. And consciousness is not just a synonym for awareness. As I use it, it’s meant to capture that process of reflection and deliberation characteristic of “big” decisions like deciding to get married or whether to take a job.



Filed under Consciousness, Philosophy, Psychology

2 responses to “Thinking About the Libet Experiments (Again)

  1. It is really hard to figure out what, exactly, these experiments prove. They are interesting, but totally unsurprising. Given the speed of neural transmission, it was guaranteed that something in the brain would predict movement before it happened. It was also pretty much guaranteed that something would precede “the decision” to move… in the same way that a lot of “getting up” related activity happens in my brain before I actually get up in the morning.

    I find myself wondering what role the researchers instructions should have in our interpretation of the results. I am only moving my finger because he told me to… and so in some sense the start of my voluntary decision should be the time-point at which his instructions are given… shouldn’t it?

    • Gary Williams

      Hi Eric,

      I think you are right. The instruction to follow the directions of the experimenters is the direct control parameter that structures the rest of the action. I wrote about this while ago in terms of Jaynes’ notion of a conscious “struction”, which is an instruction the conscious mind gives to the nonconscious mind which the nonconscious mind carries out effortlessly and then sends the results to consciousness. This is what I think the experimental instructions accomplish.

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