Benjamin Libet: A Jaynesian Interpretation

In 1980s, Benjamin Libet performed a psychophysical experiment on voluntary will that has sparked ongoing controversy regarding its interpretation and implications. Take the phenomenon of freely willing your hand to move. This is a phenomenon well-known to us all. Libet’s experiment was aimed at uncovering the extent to which unconscious processes precede the awareness of our decision to freely move. It had long been known that a “readiness potential” precedes voluntary action up to a second before the action takes place, a considerable amount of time neurally speaking. Libet’s reasoning for the experiment was as follows: if the conscious willing of the hand is causally efficacious it should precede or arise around the time when the readiness potential starts. Using a clever timing mechanism, Libet discovered that the readiness potential start 550 ms before the voluntary action and that the conscious willing is reported only 200 ms before the action. There is thus a “lag” or “delay” in consciousness behind the unconscious processing. Libet himself took this as evidence that conscious decisions for action are preceded by unconscious processing and that our traditional notion of the will as a commander is thus mistaken. All the will can do, says Libet, is “veto” an action. Libet concluded that volition is thus largely an illusion, with unconscious processing determining what we are going to do before we have a conscious awareness of making a decision.

But is that the only way to interpret this experiment? Surely not.  In fact, Julian Jaynes’ notion of a “struction” indicates that consciousness actually plays a powerful role in our mental economy, far beyond that of a “veto” function.  In the experiment, the conscious awareness of a decision was timed by a clock mechanism. The subjects were instructed to watch a spot of light revolve and report in clocktime where the spot was at the moment they felt they had decided to move spontaneously. Because the readiness potential always started 350 ms before the subjective decision to move (according to the clock), Libet concludes that the conscious will is not actually making the decision, but only capable of “vetoing” what the unconscious had already decided.

If look closely however, we can see a potential role for consciousness in terms of structions i.e. conscious instructions. Say you are the subject and you are tasked with making a spontaneous move and then reporting the time at which you had decided to move. One would likely narratize this goal in your head, perhaps rehearsing the instructions giving to you by the examiner. This would be the struction that guides your overall behavior in the experiment. Let’s call this conscious instruction to follow the experiment Struction A. Struction A would of course be operative in a temporally extended way throughout the experiment, otherwise you would not be able to obey the instructions of the experimenters. Furthermore, let’s assume that after making a conscious struction, the unconscious mind would need time to “obey” and “carry out” the struction.

This post-struction processing might account for the readiness potential and unconscious processing before the actual decision, but what about the 350 ms delay between the start of the readiness potential and the report of conscious will? Let’s assume that there would be two basic structions in the overall task. Struction A would be the metacognitive operator that guides the overall behavior so as to follow the instructions of the experimenter. Struction B would be the struction which actually gets reported as the conscious decision to move. Given that structions are brain processes, it is not surprising that brain activity would precede Struction B and that brain activity would follow Struction A. Moreover, given that structions are instructions from the narrative mind to the unconscious, it is not surprising that the actual implementation of Struction A takes processing time. But if you look at struction B without accounting for Struction A, it would certainly seem that conscious willing “lags” and never makes decisions itself (except to veto). But if we understand the way in which Struction A keeps the subject focused on the task at hand in a time-extended way, then it becomes clear that Struction A, in some sense, causes the entire half-second processing of the readiness potential, the conscious Struction B, and then the action itself. If you isolate Struction B from Struction A, it seems like consciousness cannot actually initiate decisions, but only “tags along” or gets “referred backwards” so as to seem as if consciousness is making decisions. But if we look at how the temporally extended decision to follow the experimenters directions keeps the subject on task so as to initiate Struction B, we can account for the “preliminary” unconscious processing of the readiness potential for Struction B without losing sight of overall place of conscious structions within the cognitive economy (guiding behavior at the abstract level of propositional attitudes through interiorized narratizing).

In summary, here’s what I think is going on. Struction A is made by the subject. This is a conscious willing, an “instruction” sent to the unconscious or subliminal mind for processing and execution. This instruction sends a command signal to the unconscious to prepare for the tasks of spontaneous decision making and the reporting of time. Unconscious processing takes place in the form of readiness potentials, which was catalyzed by the conscious command (which is experienced as interior narratizing). The unconscious processing initiated by Struction A sets up Struction B, the “spontaneous” willing, which is then reported as the actual spontaneous decision (according to the instructions of the overall experiment). If the subjects had been trained to extend their introspective awareness to include Struction A, then Libet would have concluded that consciousness actually does influence the action, albeit in a time-extended way through abstract executive control (acting and vetoing). But because Libet focuses the conscious report only around Struction B and not the total phenomenological experience, he failed to see how the unconscious readiness potentials which preceded Struction B were themselves preceded by Struction A, which was the conscious instruction to actually carryout the task of spontaneously making a decision.

The general lesson here is that conscious decisions are temporally extended because they operate over longer time periods that half second spontaneity. In fact, spontaneous finger-flicking is not a good model of how conscious volition works. For example, I can consciously instruct myself to raise my arm 10 minutes from now and ff course there will be unconscious processing occurring between the initial struction and when I raise my arm 10 minutes later. But it doesn’t follow that just because unconscious processing occurs before the arm raising that my conscious struction wasn’t the actual impetus for the action.



Filed under Consciousness, Philosophy, Psychology

3 responses to “Benjamin Libet: A Jaynesian Interpretation

  1. Thank you very much for clarifying the isssue. It helped me a lot. One little question, though. And please forgive me if I’m misguided. Is it not the case that “struction A” and “struction B” is qualititatively different? Whereas “struction A” is a metacognitive operator that ‘instructs the person to construct the performance’ (or the task or whatever it is), “struction B” seems to me just a kind of ‘instruction’ in an ordinary sense to tell the person ‘now do it’ (or ‘I can do it and will now’ in the case of the task). My point is whether or not it is more proper to call “struction B” simply ‘instruction (to oneself)’. Hope I made myself clear. Thank you again. Yosuke Yanase

  2. Gary Williams


    If I understand you correctly, you are right in pointing out that there would be phenomenal differences between the forms of instruction. Struction A would probably seem more like an interior conversation with oneself, whereas struction B would be as you described it, merely a catalyst or push. I would imagine that struction B would be more “phenomenally transparent” than struction A in virtue of being less “explicit” in ones mind.

  3. Thank you, Gary. Yes, that’s what I mean. If I can use an analogy here, “struction” (=your ‘struction A’) is an order to an AI like HAL and “volition” (=your ‘struction B’) is pushing a switch. You ask HAL to do something but you have no idea of the program and mechanism of HAL. You wait while HAL works for you, until HAL turns on a green light. You then can push the switch (=volition) or decide not to (=veto). HAL ‘constructs’ a program ‘instructed’ by you, but you only ‘instruct’ HAL to (or not to) execute the program and you don’t really ‘construct’ anything. Because this is an analogy, it inevitably introduces some kind of inexactness, but I hope this analogy makes some sense. Thank you.

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