Sunday, August 1, 2010

"MIND TIME" by Benjamin Libet (and some thoughts of mine)


Libet (2004) - MIND TIME (Harvard University Press) - reports two very important findings concerning two important aspects of consciousness: awareness and free will.

Finding 1 [about awareness]: The brain needs a relatively long period of appropriate activations, up to about half a second, to elicit awareness of the event. (p. 33)

Finding 2 [about free will]: The process leading to a voluntary act is initiated by the brain uncousciously, well before the conscious will to act appears. (p. 136)
The conscious will could decide to allow the volitional process to go to completion, resulting in the motor act itself. Or, the conscious will could block or "veto" the process, so that no motor act occurs. (p. 138)

These two findings (F1 & F2) invites two tough questions.

Question 1 [from F1]: How can one explain the fact that subjectively we feel that we are aware at the actual moment of a sensory event? (pp. 70-71)

Question 2 [from F2]: If the veto itself were to be initiated and developed uncousciously, the choice to veto would then become an uncouscious choice of which we become conscous, rather than a consciously causal event. (p. 145) [Translation: Is free will to be totally denied?]

Let's first take a look at the two findings. I'll add my analogy of a football coach to explain the function of consciousness when I mention the second finding.

F1: The brain needs about half a second to elicit awareness of the event.


Before we discuss, we need to clarify some of the possibly confusing concepts.

First, about consciousness and mental functions. Consciousness is only a tiny (and edited) reflection of mental functions. As Libet says, "many of our mental functions are carried out uncousciously, without conscious awareness. (p. 2)" To borrow Edelman's term, many of mental functions are carried out nonconsciously.

The second point is about awareness being the essential featrue of consciousness. Libet maintains that "the essential feature of introspective reports of conscious experience is awareness, or being aware of something." (p. 13) For Libet, the different contents of awareness do not matter. He argues from his experimental evidence that "awareness per se is a unique phenomenon, and it is associated with unique neuronal activities that are a necessary condition for all conscious experiences. (pp. 13-14)

The third point is the difference between the awareness of a signal and the detection of a signal. Whereas becoming consciously aware of a signal requires the relatively long time, detecting a signal can occur unconsciously, without any awareness of the signal. (p. 34) For example, we can discriminate between two different frequencies of tactile vibration, even though the intervals between two pulses in each vibratin frequency are only a few milliseconds (msec) in lenghth. (p. 33)


Libet discuss 12 points from this finding. Here are the first five. For some readers, Point (1) may sound like a confirmation of the contention of Julian Jaynes, (2) that of Stephen Krashen. The remaining three points may be like scientific affirmation of our common experience.

(1) Perhaps all conscious mental events actually begin uncousciously before any awareness appears. ... Thoughts of various kinds, imaginations, attitudes, creative ideas, solving of problems, and so on initially develop uncousciously. Such uncouscious thougths only reach a person's conscious awareness if the appropriate brain actitivies last a long enough time. (p. 107)

(2) Vocalizing, speaking, and writing fall into the same category; that is, they are all likely to be initiated uncousciously. ... In the case of speech, for example, this means that the process to start speaking, and even the content of what is to be spoken, has been initiated and prepared unconsciously before the speaking begins. If the time-on requirement for awareness holds here, it would be manifestly impossible to rapidly speak a series of words, in the usual fashion, if one first had to become consciously aware of each word. ... In smoothly flowing speech, words are allowed to appear "on their own," in other words, they are initiated unconciously. As E. M. Forster reportedly stated, "How can I tell what I think until I see what I say?" (p. 108)

(3) The playing of a musical instrument, like the piano or violin, or singing must also involve a similar uncouscious performance of the actions. (p. 109)

(4) All quick behavioral, motor responses to a sensory signal are performed uncousciously. These are responses that can be made withing 100-200 msec after the singal, well before arareness of the signal could be expected. Many actions in sports fall into this category. (p. 109)

(5) Uncouscious mental functions can proceed at higher speed, if they are carried out by shorter-lasting neuronal activities. This implies that the series of uncouscious processes involveld in solving a problem can proceed speedily, each brief process after another. (p. 111)

It seems that these implications are particulary important for those of us obsessed with the modern notion of conscious-self, the grand master that takes a complete control of our action. We seem to need not just psychatry but also neuroscience to be free from this notion. (If you're a Buddhist, you'd have no trouble in the first place.)

F2: Our conscious will does not really initiate our action; it can only veto the action. (Or analogy of a football coach)

This finding was actually implied in the five points above. Our conscious will is not the grand master of our action.

At this point, I'd like to indulge in some analogical thought.

Consciousness is like a boy on an elephant, trying to control the elephant's move. His control is not to his satisfaction, because, after all, it is the elephant that moves. Indeed, it is the elephant that initiates the move. However, once the elephant begins to move, the boy can lead it to move in a certain direction over the long period of time. He is not useless.

Or, if I may introduce my analogy, consciousness is like a football coach. He may try to, but he cannot dictate every single move of his eleven players. Contrary to his ambitious expectation, the coach can only attempt to change the course of actions taken by the players after he saw their movements. Likewise, the control our consciousness has over our actions is only delayed and very limited.

What you should do as the football coach/concsious will is let the player/body practce and play/act. You just give a general instruction.

Don't try to give specific command to every sigle movement of the players/body. You'll never succeed for you cannot give commands as specific or as fast as the play/act demands. Should you synchronize the movement of the players/body with your command, the play/act is awefully slow and not functional at all.

When you direct the players/body generally, always remember that you (the coach/conscious will) is not the actor. You're not even the agent (at least as you wish to be). The players/body are the actor. They are the agent, too, althogh they are incapable of representing their collective sense of agency by themselves. Each one of the eleven players moves respectively in his complex interaction with the environment (the ball, the other players, the field and so on). He improvises his complex action because he responds to the complexity of the situation in which he's embedded. Only you, the coach, who try to observe the entire game can have a unitary sense of the entire game.

You, the coach/conscious will, can only help and direct the players/body in a lmited way. However, you're not useless. Far from it. Your wise long-term strategy can make the players/body better in the long run. However indirect and delayed your connection is to the players/body, you're the one that is the most responsible for their actions.

Yet, because you're not the actor or agent, don't forget that your direction does not constitute the action. If you spend most of the time of practice just talking, not letting the players/body move, you're completely mistaken. The coach doesn't play; consciousness doesn't act. It's categorical. It's a categorical mistake if the coach thinks he can play in the field or if you as the conscious-will are the body movement.

You can't even make the players/body move in the first place. It is the players/body that initiates the move. You only clap your hands and cheer them up as the players enter the field, reminding them of the general strategy you taught. When they fail miserably, you can stop the game and give them a new strategy. But when the interval is over, you keep staying outside of the field and start observing again.

This is how I interprets Libet when he says: The process leading to a voluntary act is initiated by the brain uncousciously, well before the conscious will to act appears (p. 136); The conscious will could decide to allow the volitional process to go to completion, resulting in the motor act itself. Or, the conscious will could block or "veto" the process, so that no motor act occurs (p. 138).

OK, now that explanation of the two findings are over for the moment, let's go back to the tougher part of the argument: the two questions that the two findings invite.

Q1 [from F1]: How come we don't usually feel we're as late as half a second in our awareness of the sensation?

This question comes from Finding 1: The brain needs about half a second to elicit awareness of the event. But how did Libet know this in the first place? Isn't 500 msec too long for a neural response?

Libet, in his exceptional experimental environment (which is completely ethical, of course), had electrode contacts sitting on the surface of the primary somatosensory cortex of the subject (the primary somatosensory cortex is the area of cerebral cortex that receives the directo sensory input from all the areas of the body and skin). Electroical stimulation to this area elicits a conscious sensation (awareness) in some specific skin or body structure (we don't feel any sensation in the brain itself). (p. 35)

The most interesting finding was that, to elicit a report of a weak, threshold-level sensation, the stimulus had to continue for about 0.5 sec. If the stimulus is shorter than that, the subject may detect it at the sub-conscious level, but not become consciously aware of it. Therefore, it is argued that to be conscious/aware of a stimulus takes about half a second after its onset (the duration time of half a second is called "Time-On").

Given that, though, the finding is couter-intuitive because we don't usually feel that we're so late in sensation. As I tap the keyboard now, I feel that the touch and the sensation, more or less, at the same time. The gap of half a second between the touch and the sensation seems too long.

Then comes a new experiment (p. 72-79). Libet stimulated the subject in two different places: one in the sensory cortex and the other in the skin. The time when the the sensory cortex is stimulated is to be called "neuronal time", whereas the time when the subject become conscious/aware of the perception (produced either by the stimulus in the sensory cortex or the one in the skin) is to be called "subjective time." So there are two lines of stimulus-perception.

(SC) Stimulus in the cortex ==> (PSC)Perception of SC (to be felt, though, in some part of the body, not in the brain itself)
(SS) Stimulus in the skin ==> (PSS) Perception of SS

After learning to distinguish the two different Stimulus/perception (SC ==> PSC and SS ==>PSS), the subject was given the two types of stimulus either at the same time or at different times.

(SC/SS) SC and SS are given at the same time.
(SC->SS) SC is given first and then SS.
(SS->SC) SS is given first and then SC.

In SC/SS, the subject reported that they felt that SS was given first, althogh both SC and SS were given at the same time.

In SC->SS, the subject also reported that they felt SS before SC when the delay of SS after SC is a few hundreds of miliseconds; the subject reported that they felt the sensation almost simultaneously when the SS is given 500 msec later than SC.

In SS->SC, the subject always felt SS before SC.

A conclusion to be drawn here is that stimulus in the skin was subjectively felt earlier than the stimulus in the cortex. Given the physical distance between the skin (where the skin stimulus is given) and the cortex (the destination to which the neural message of the skin stimulus is to be transmitted), it is unlikely that SS ==> PSS is faster than SC ==> PSC. (The opposite would be quite possible considering that SS ==> PSS should take a longer time because of the physical distance of the transmission of the stimulus). The paradox is this: how come the subjective time is perceived earlier than the actual neuronal time.

The hypothesis that Libet gives to account for the paradox is that there must be a subjective referral of the timing for the experience back to the time of the time of the neuronal time (p. 75). The subjective time must be created or invented to be perceived before the physical stimulus time. In other words, the brain cheats us into believing that the brain is giving a perception more or less simultaneously with the actual experience.

Given that the brain often edits the information to make a coherent story to our consciousness, I guess this trick is not so surprising. After all, the evolution has made the brain as it is so that it promotes our survival. The evolutionary brain is not committed to the truth (The chance of survival should be higher, if it is closer to truth, though.)

Moreover, we have just seen that the brain "refers" the stimulus in the cortex in a different place of the body. If there is a subjective projection in space, we might guess that a subjective projection in time is also possible.

A candidate for this subjective projection in time is unconscious suppression of vision. When a highly prudish man is shown a picture of a naked lady, he might report seeing something quite different and he is not lying (a Freudian topic) (p. 71). If he perceived the naked lady and was aware of the image simultaneously, the brain would have no time to suppress and distort the image. If we assume that there's a time lag between the stimulus and the awareness/consciousness, we can readily explain that the suppression is possible because the brain has time to distort the content of the vision.)

So there's an answer to Q1. We don't feel the time lag between the stimulus and its awareness because the brain cheats us and creates the subjective time. This is probably a better, or fitter way of living when we have the neural delay of 500 msec and still want to believe that we're a reasonable being, responding to the environment.

Additional note: I now remembered that a tape recorder for professional use has two contacts to the tape. The first contact to the tape is to pass on the sound that the microphone picks up (that is, for recording), and the second contact is to listen to the recording that the first contact has made only a short time ago (that is, for monitoring). Thus, the technician monitoring on the professional tape recorder listens to the music always a bit later than the actual performance. This delay is necessary to check that the sound was really recorded. To respond to a professional demand, you have to pay a price.

However, the usual tape recorder has only one contact for recording only. Someone who "monitors" the recording on such a tape recorder actually only listens to the sound that the microphone picks up, the sound that is to be recorded onto the tape. He therefore cannot really monitor the recording, and on some unfortunate situations, he may find that the sound was not really recorded at all (or awfully recorded) because of some mechanical problems only after the music was over.

Apparently, the professional tape recorder is more functional. However, it must have been a rather uncomfortable experience when someone monitors on the professional tape recorder and sees the music performance at the same time. The sound he monitors comes slightly after the vision. The sound and the vision do not synchronize. If it had been technically possible, people would have wanted a device to listen to the recorded sound for monitoring as he sees the visual image. A special tape recorder which can magically project the recorded sound earlier than the actual recording time to synchronize the sound with the vision would be a solution. Our brain may be like such a magical device.

Q2 : If the conscious will is actually initiated unconsciously before and the function of the consciousness is only to veto the continuation of the unconscious initiation, is it not the case that the conscious veto, too, was actually initiated unconsciously? Aren't we completely determined unconsciously and there is not such a thing as free will?

This question which stems from F2 (Our conscious will does not really initiate our action; it can only veto the action) is tougher because, it seems to me, the hypothesis that Libet provides to deal with this question is not as strong as the hypothesis in Q1. The hypothesis Libet provides in Q2 is only a possible hypothesis, not necessarily a plausible one.

If the veto is part of consciousness, it is likely that the veto-consciousness is also initiated unconsciously. That leads to total denial of our free will as we know it. To which possibility, Libet proposes as follows:

I propose, instead, that the conscious veto may not require, or be the result of, preceding unconscious processes. The conscious veto is a control function, different from simply becoming aware of the wish to act. (p. 146)

He defends this proposal as follows:

There is no logical imperative in any mind-brain theory, even in identity theory, that requires specific neural activity to precede and determine the nature of a conscious control function. And there is no experimental evidence against the possibility that the control process may appear without specific development by prior unconscious processes. (p. 146)

OK, it is possible. And since I don't have a more plausible hypothesis, let's assume that the conscious veto doesn't need prior unconscious processes. An answer is given: In the veto function of consciousness, we have free will.

But still, a new question arises.

Q3: Is what we call 'free will' only the veto? Is our 'free will' only a matter of cancellation of an ongoing processes that was initiated unconsciously? Are we 'free' only in such a short term? Are we otherwise determined?

Here's my attempt to give an answer.

I have the short term freedom of the veto, but that's not the end of the story of my freedom. I attain something close to 'free will' or at least I can influence my future course of action in the long run by externalizing my consciousness to make it the environment of the autopoietic system, that is commonly called 'I'.

Providing that I'm an autopoietic system, my action is self-produced by the complex interaction of the multitudes of components within the system. This view accords with the above view that our action is unconsciously initiated, only partially realized in consciousness later. In this sense, we have almost no free will.

However, the consciousness that I become conscious of, typically in the linguistic form, becomes conspicuously physical. The consciousness becomes a sound that echos in my mind, which is retained in my short term memory just like sounds from the outside world (i.e. the environment).

To make the argument simpler, let's suppose that I write down the consciousness on a piece of paper "DON'T EAT TOO MUCH." I always carries the piece and put it on the table when I eat.

The message "DON'T EAT TOO MUCH", which originally was in my mind, is now externalized. It is part of the environment to the system called "I". The piece of paper is beyond the immediate influence of "I". It stays there irrespective of my status. Even when my uncousciousness wants otherwise, the message stays there and becomes an independent stimulus to the system called 'I' and affects 'I'. In other words, an Ex-'I' affects the current 'I'. The current 'I' has only the veto function over the action that was initiated my unconsciousness. But this ex-'I' which is now the enviromnent to the system constantly 'irritates' me as an independent stimulus. ('Irriation' is a term used by Luhmann in his systems theory.)

Let's also suppose that I have a variety of other means to guide me into the direction that I want. I often say my principles to my friends and they sometimes quote these to me or ridicule me when I fail to respect these principles. I buy books that are very close to my free will and make it a rule to read them regularly. I keep a good TO-DO list so that I can behave as I wanted to behave when I planned.

Despite these various means, I may still fail to do what I wanted to do. But over a long period of time, if I keep these part of my environment, constantly affecting or 'irritating'the system ('I'), independent of the status of 'I', I may successfully lead myself to do what I wanted; I may even change myself in a way I wanted. I'd like to call this sort of guidance "free will".

This may be a distortion of the concept of 'free will', but this is my current response: You have free will: You can choose to do what your conscious will wants, or at least you can influence yourself to do what your conscious will wants, by changing the environment in which you're embedded.

Externalizing yourself is what you do in psychiatry and narrative and both have some special functions which otherwise cannot be achieved.

Do we have layers of us?: nonconsciousness / primary consciousness / higher-order consciousness / externalized consciousness in some linguistic form. Do we have a still higher layer, publicly shared wisdom in some linguistic form? Can we be free to the extent we make ourselves go up the layers?

Let me think more. Thank you for your reading.

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