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Libet and the role of consciousness

Libet and the role of consciousness

DJPavel
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Posted 04/29/08 - 08:02 PM: Subject: Libet and the role of consciousness	#1
I find it puzzling that most people don’t know who Benjamin Libet was and what he did. I would think that being told that the belief in our conscious mind to be in control of our volitional acts is an illusion would be almost like being told that the Earth is not flat, despite what our senses tell us. Maybe the discovery is simply waiting for our culture to catch up with the new ways of looking at the old (and I would argue confused) notions, such as “free will”. I keep wondering if Libet’s research is not widely accepted on some rational grounds or is it simply an emotional response to a counterintuitive theory, the kind that we have seen throughout the history of science (remember Albert Einstein and Niels Bohr?). Considering the rational grounds, I’m not aware of any argument that demonstrates a logical inconsistency between Libet’s discovery and some other “hard to deny” empirical fact (or an a priori assumption). There have been attempts to render “free will” incompatible with determinism (e.g. Peter van Inwagen) on logical grounds, but alas, no proof. There have been efforts to produce thought experiments, like Newcomb’s paradox, to appeal to our common sense, but again, nothing but intuition. So, I think it’s fair to say that, at least at this point, there’s nothing illogical about Libet’s discovery – its conclusions cannot be ruled out analytically. Assuming the whole research is not a hoax and replicable in the labs (which I believe it is), the remaining explanation for the wide nonacceptance by the pop culture is simply an emotional reaction. It looks like yet again we’re dealing with some kind of strong built-in cognitive bias towards “being in control”. Anything discovered that undermines this sense of control produces an unpleasant psychological state (cognitive dissonance). We search for ways to rationalize ourselves out of this state, and if we can’t, the only strategy out is simply to reject the news. Is that what’s going on here? But let’s leave biases for another discussion. What interests me is how we can explain the role of consciousness in the light of Libet’s discovery. Embracing methodological naturalism as the explanation criteria (and assuming monism), what evolutionary advantage does the state of being conscious offer? It would be hard to imagine that such a resource hogging function would be epiphenomenal, simply a side effect of some other important biological mechanism, by accident. As evolutionarily fit and trimmed as we appear to be, it doesn’t make much economic sense to have consciousness around, does it? So, it must be providing some survival benefit. Libet himself proposed, in an attempt to save the “free will” I suppose, that consciousness provides “veto power” to change the “decision” of the unconscious motor cortex. But that simply pushes the problem further away, for the obvious question now would be, who decides to veto? This chase after the prime mover can lead to an infinite regress, simply because of the subtle presumption that there is an ‘undetermined decider’ somewhere. As I argued elsewhere, however, the notion of “decider” is a pragmatic distinction in our language just like the word “random” (maybe with the exception of Quantum Mechanics), simply due to insufficient amount of information to grasp what’s really going on down there. If we look at our brain with something like fMRI, there’s more and more evidence that for every decision we make, there’s an underlying causal chain of electro-chemical events, as opposed to some ever elusive homunculus pushing levers. That is, the notion of “decision” appears to be nothing more than an abstract term for “specific electro-chemical process”, sort of like “heat” stands for “kinetic energy from vibrating atoms” – one does NOT cause the other. With such observations in mind, how can we explain the role of consciousness then? This is what occurred to me while spending endless hours practicing hockey moves and getting frustrated with my motor cortex for being too darn slow in getting things right. The “simply getting old” explanation aside, I speculated that consciousness is not a “veto” mechanism, it’s simply a feedback-adjustment mechanism. At any given time, the physiological state of the body “wants” something, i.e. satisfy hunger, execute a move, etc. How to get what it wants depends on the knowledge (the neural wiring of the brain) that comes from experiencing and interacting with the environment. Building this knowledge requires a trial and error mechanism that constantly senses the world out there, reacts to the stimulus coming from it, evaluates the result against the “want”, and adjusts/strengthens the knowledge. The sensing part IS what we refer to as being conscious or aware. This might sound like old news, but the key here is that consciousness does not cause the reaction, it provides feedback by sensing the reaction’s results. (the motor cortex is just an example. Any other electro-chemical mechanism that produces a physiological state or response (e.g. hormone releasing glands) is adjusted in a similar fashion) To put it differently, such feedback mechanism is consistent with Libet in a sense that the motor cortex is preprogrammed to react to a certain environmental condition. When a stimulus occurs, we have an automatic response with our consciousness being “carbon copied”. As the consciousness senses the consequences of the response, certain neurotrasmitters are released. If it's something like dopamine, the “want” state is satisfied and the neural connections of the response producing mechanism get strengthened; if not, they get modified until the next time the same condition occurs. The brain of course integrates all sensory information in such a way that we don’t experience the automated response. We experience “choosing” to respond that way. Without such feedback mechanism of sensing and adjusting, a “zombie” would never be able to learn. Without the learning ability, in order to survive, the zombie would have to rely on a genetically built-in database of responses to every possible stimulus in the environment. Such “design” would obviously be much more inferior, in an economic sense, to something that learns and adapts to the surrounding conditions “on the fly”. Everything I know about psychology appears to be consistent with this model. Take classical conditioning as a good example. Infants rely only on unconditioned responses in dealing with the environment: you touch the palm of their hand with your finger, they grab it. As they interact with and sense the environment, however, their brains start associating things together. Biting of a dog causes an unconditioned response, but hearing growling that comes with the dog teaches the maturing infant that two come together. The child now has a conditioned response every time it hears growling, as it flees. This decision to flee, however, is executed prior to being aware of it, because the child's brain already has an association of growling with something that produces an unconditioned response (of fleeing). A zombie child would never have that association, and by the time the dog would bite it, it would be too late. Classical conditioning thus has a clear survival benefit: the faster I can react to anything that is associated with being bitten, the more likely I’ll be better off. What do I need to build these mental associations? I need to be sensing the environment, i.e. I need to be conscious! Building conditioned responses goes much further than reacting to a growling dog. As infants grow, they learn to recognize geometrical figures, human emotions, and language. This process of trimming neural connections eventually produces a finely tuned machine that is quick to respond properly whether you’re riding a bike, laughing at a joke, or philosophizing a theory of consciousness. All of such activities require understanding of a broad context in which heard or seen things are expected and interpreted. The process of building this context takes years, but once it’s there, the response to a stimulus, whether in a joke or your friend’s gesture, is automatic. The consciousness lacks behind and acts as a feedback circuit to see if the response satisfied a certain physiological state. This is of course not a theory by any stretch, just a speculation by a curious amateur, but I’d be interested in hearing any feedback; especially whether the model is conceptually consistent. And if it is, I’m wondering if anybody has suggested it before and done some lab work to try to validate it. P.S. If you happen to know how computer networks work, there’s a really good analogy to be made between the model I propose and a Layer 3 network switch. The control plane of such a switch is “sensing” what’s going on out there on the network (congestions, dead links, etc.) and makes sophisticated decisions about how the switch should route the traffic. It then programs the ASICs of the data plane which follow simple “dumb” rules to switch every incoming packet. The data plane doesn’t consult the control plane how it should switch an incoming frame, it does it automatically, until it is reprogrammed by the “higher” module to do otherwise. In this analogy, the conscious module of the human brain is the control plane, while the motor cortex (and anything produces a physiological response) is the data plane. As a matter of fact, any adaptive system that is split into two control and execution modules would be a good analogy. DJP Edited by DJPavel on 04/30/08 - 07:17 PM

rakis
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Posted 05/01/08 - 01:49 PM:	#2
why don't you write in thread "how consciousness is possible?"

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