http://www.consciousentities.com/?p=233
One of the most frequently visited pages on Conscious Entities is this account of Benjamin Libet’s remarkable experiments, which seemed to show that decisions to move were really made half a second before we were aware of having decided. To some this seemed like a practical disproof of the freedom of the will - if the decision was already made before we were consciously aware of it, how could our conscious thoughts have determined what the decision was? Libet’s findings have remained controversial ever since they were published; they have been attacked from several different angles, but his results were confirmed and repeated by other researchers and seemed solid.
However, Libet’s conclusions rested on the use of Readiness Potentials (RPs). Earlier research had shown that the occurence of an RP in the brain reliably indicated that a movement was coming along just afterwards, and they were therefore seen as a neurological sign that the decision to move had been taken (Libet himself found that the movement could sometimes be suppressed after the RP had appeared, but this possibility, which he referred to as ‘free won’t ‘, seemed only to provide an interesting footnote). The new research, by Trevena and Miller at Otago, undermines the idea that RPs indicate a decision.
Two separate sets of similar experiments were carried out. They resembled Libet’s original ones in most respects, although computer screens and keyboards replaced Libet’s more primitive equipment, and the hand movement took the form of a key-press. A clock face similar to that in Libet’s experiments was shown, and they even provided a circling dot. In the earlier experiments this had provided an ingenious way of timing the subject’s awareness that a decision had been made - the subject would report the position of the dot at the moment of decision - but in Trevena and Miller’s research the clock and dot were provided only to make conditions resemble Libet’s as much as possible. Subjects were told to ignore them (which you might think rendered their inclusion pointless). This was because instead of allowing the subject to choose their own time for action, as in Libet’s original experiments, the subjects in the new research were prompted by a randomly-timed tone. This is obviously a significant change from the original experiment; the reason for doing it this way was that Trevena and Miller wanted to be able to measure occasions when the subject decided not to move as well as those when there was movement. Some of the subjects were told to strike a key whenever the tone sounded, while the rest were asked to do so only about half the time (it was left up to them to select which tones to respond to, though if they seemed to be falling well below a 50-50 split they got a reminder in the latter part of the experiment). Another significant difference from Libet’s tests is that left and right hands were used: in one set of experiments the subjects were told by a letter in the centre of the screen whether they should use the right or left hand on each occasion, in the other it was left up to them.
There were two interesting results. One was that the same kind of RP appeared whether the subject pressed a key or not. Trevena and Miller say this shows that the RP was not, after all, an indication of a decision to move, and was presumably instead associated with some more general kind of sustained attention or preparing for a decision. Second, they found that a different kind of RP, the Lateralised Readiness Potential or LRP, which provides an indication of readiness to move a particular hand, did provide an indication of a decision, appearing only where a movement followed; but the LRP did not appear until just after the tone. This suggests, in contradiction to Libet, that the early stages of action followed the conscious experience of deciding, rather than preceding it.
The differences between these new experiments and Libet’s originals provide a weak spot which Libetians will certainly attack. Marcel Brass, whose own work with fMRI scanning confirmed and even extended Libet’s delay, seeming to show that decisions could be predicted anything up to ten seconds before conscious awareness, has apparently already said that in his view the changes undermine the conclusions Trevena and Miller would like to draw. Given the complex arguments over the exact significance of timings in Libet’s results, I’m sure the new results will prove contentious. However, it does seem as if a significant blow has been struck for the first time against the foundations of Libet’s remarkable results.
15 Comments »
1.
Considering that usually in science, extraordinary claims need to be backed-up with extraordinary evidence, it’s always seemed strange to me that Libet’s findings - which were clearly open to interpretation - were taken by so many, so quickly, to be such strong evidence for the highly counter-intuitive, and counter-experiential idea that free will is an illusion.
For me, in accepting that materialism (as currently understood)is almost certainly wrong, and looking towards some kind Chalmers-like monism, or even dualism, as an alternative, it’s never actually been necessary to appeal to the supernatural, rather only accept that there’s so much that we are yet to fully grasp. Yet the materialist mainstream generally seem bent on denial of alternatives, in what appears to me to be some latent overreaction to the threat of returning to a world dominated by non-scientific superstition. For example, I’d argue that it’s not so much Descartes’ dualism they really object to as so much the belief system behind the idea.
The over-ready acceptance and use of Libet’s evidence was symptomatic of this state of affairs.
Comment by Matt — September 26, 2009 @ 10:55 am
2.
I’ve wondered about the connections made around Libet’s research in the past, even before these new findings were published. The determinists are looking at Miller and Trevena’s research and claiming that it does not contradict Libet’s preferred conclusion [at least, they claim, it's not an outright contradiction]. Only time and more data will determine this, I guess.
Comment by 2bsirius — September 26, 2009 @ 3:50 pm
3.
Libet would be rolling in his grave if he could- and he’d have no choice about it.
Anyway, it is curious that many people were quick to claim and cling to Libet’s work and its most popular interpretation for support of the idea that human beings had no free-will.
But I’m a materialist and I don’t believe the cleft caused by Libet’s work divides materialists and dualists — or Chalmer monists (everything is consciiousn). I think the divide has been between i) people who accept Libet because they think it’s bad ass to do so; and 2) others who understand that the folk in prior category are trying to be trendy, in an academically needy, carelessly hipster sort way.
So much for pop-culture trends in psychological “science.”
Comment by DATY — September 27, 2009 @ 2:59 am
4.
To borrow a metaphor from Hofstadter, looking for freewill on the sub-second neural level is like looking for a traffic jam inside of a single car. You simply won’t find what you are looking for. One must zoom out to a higher order of organization in order to find voluntary action.
Comment by Gary Williams — September 27, 2009 @ 2:22 pm
5.
Some of you seem like you’ve been waiting for a good reason to talk about why people who look at Libet’s results and claim that they make a good case against free will are going about it all wrong. Let’s not forget that if you’re convinced that we have free will, you must be holding out for some pretty major revolutions in the physical sciences. You’re counting on some kind of data to be generated that can only be dealt with by a major reworking of some of the most basic(and experimentally successful in the sense that they can be used to make accurate predictions) principles of modern science. I think for the most part people who accept Libet’s results do so because free will doesn’t really make sense under current scientific paradigms, and because of that it’s easier to accept that free will is an illusion than it is to be certain that a major scientific revolution is on its way that will account for free will and make everyone confortable about being in control of their own lives again.
It’s not about “trying to be trendy, in an academically needy, carelessly hipster sort way,” its about accepting the view of the world that actual working theories and data provide. Being so certain that free will can be proven seems to be based more on faith and motivated by your discomfort with the alternative than by any actual evidence.
Comment by Alex — September 27, 2009 @ 4:17 pm
6.
After looking carefully into the experiment, it appears to me that the RP moment is still the moment when the decision is made. Even as is described as the preparation to take a decision, I would argue that is the moment when the brain does a little rehearsal of what is going to become conscious of. The LRP appears to be a moment of decision, but is an illusory one, the decision is taken prior to the moment of consciousness about it. Libet is still right in my opinion.
Comment by Doru — September 27, 2009 @ 6:07 pm
7.
If physicists or chemists conduct an experiment and observe a new relationship between the observed behaviour of things and the data, they try to explain it as was done here, but they do so in terms of models that have a reasonable foundation and proven record of explanation.
Here, I see people doing some decent experiments but drawing some facile and worthless conclusions talking about “free will” and “free won’t” and “decision”… what does any of this mean? Of course we understand these terms in an everyday sense, but to rely on these as a scientific explanation is unbelievable.
This is an unfortunately common example, in this field, of people running before they can crawl; there needs to be a reasoned and logical foundation for the language and concepts used before the results of such experiments can be interpreted scientifically.
Comment by David — September 28, 2009 @ 1:44 am
8.
Free-will is probably one of the most important topics for philosophy, since it is a core building-block for any attempt to contruct ethics. All these experiments, although very interesting, seem to be far too simple to be used in the free-will discussion. Most decisions that really matter need to be taken in much longer periods (yes, sometimes humans are forced to make up their minds in a few seconds in emergencies). Could be that simple decisions like pressing a button, are left to random processes in the brain, since there is no need at all for reasoning or considerations. Would it be possible to make a similar experiment where asking the subject to buy a new car, or accept or reject a job offer?
Comment by Vicente — September 28, 2009 @ 7:11 am
9.
Alex,
I believe that free-will is an illusion if by free-will one means to refer to a super or meta-causal force that works above and beyond the deterministic framework of classical physics. But when I refer to free-will I am referring to Ego, to some sort of centralized locus or source for behavioral modulation or neuromuscular change–to the self that causes and is aware of such a change. No scientific revolution would need to take place in order to accommodate such a notion. But to the contrary, it took Libet’s work to make the contrary (ie, the self is illusory) considerable in the first place.
As for my contention that supporters of Libet and his conclusions about the human mind make up a gang of hipster dolts who don’t think hard and criticize the scientific literature enough, well, in my experience it’s true, not neccesarily true of course, but simply, informally speaking, true of every person I’ve ever come across who makes a reference to Libet’s work, who does so always in that air of a person speaking in facts and never without even a hint of refrain or suggestion that such research is not undeniable, may be incomplete, the data itself provided by such research questionable and interpretable in different ways. Simply put, a lot and a lot more is needed to prove Libet is even basically right. Yet one wouldn’t sense that from wading through the opinions of the folk who follow these issues.
Anyway, let’s not forget that Trevena and Miller are not doing revolutionary work. Nobody here is proposing new a paradigm.
Comment by DATY — September 29, 2009 @ 1:36 am
10.
If you identify brain as the “agent” of consciousness, then Libet’s experiments obviously prove that free-will doesn’t exist. This is the position of the physicalists.
However, idealists don’t consider the brain to be the “agent” of consciousness, but rather the “instrument” of consciousness. I’ll clarify this position. Like in a remotely controlled robot, the brain is receiving instructions from elsewhere to execute choices. Only a part of these instructions are recorded (in a memory backup facility) and this act of backup happens after these instructions race down the neural highway. What Libet’s experiments prove is the latency between the backing up and the execution of these instructions. They say nothing about the origin of these instructions, even though Libet himself jumped the gun in drawing his conclusions about free-will.
In my opinion, free-will is tied to the notion of determinism in physics. Our universe is not deterministic, even though many scientists (and philosophers) desperately want it to be. Personally, I consider consciousness to be universal and singular. It has no seat in space and time. It is something even more fundamental than space and time, its nature should be investigated in the very question of “why existence”. Consciousness pervades this universe as a field, different objects are capable of interacting with it at different levels. Animal and human brains are just some of some of sharpest antennas that have evolved so far, to interact with this field.
Comment by vakibs — September 29, 2009 @ 9:42 am
11.
I think a good perspective on free-will is present in the writings of Erwin Schrodinger, particularly in the epilogue of his legendary book “what is life” named freewill and determinism.
Comment by vakibs — September 29, 2009 @ 9:51 am
12.
Hi Vakibs
If the brain is just an interface between the “spiritual” world and the material world then, does it matter wether the laws of physics are deterministic or not in the free will discussion?
If the brain is just an interface, by what mechanisms brain chemistry has such an influence in perception, reasoning, behaviour, mood and other “states of mind”.
If mind has no seat in space and time, how does it interact with “objects” in space and time?
Unless everything is mind, idealism seems incoherent.
Comment by Vicente — September 29, 2009 @ 1:28 pm
13.
Hi Vicente
There are no two different worlds : spiritual and material. There is just one single universe, and it is independent of anything outside it (if there exists anything beyond it). Whether there exists a finite (or even countably infinite) set of physical laws that determine the behavior of the universe is the question. I believe the answer is no : the universe is non-deterministic and this non-determinism cannot be resolved away at any scale of looking at it.
Brain is no different from any other physical (material) object in the way it is influenced by the laws of physics. It is subject to deterministic laws, and at the same time it has “access” to break away from this determinism. Any object in this universe (whether that be an electron or a brain) has a “free-will” (non-determinism) that is defined by the scale of the environment that can be sensed by it (or equivalently, the amount of information about surroundings that can be represented by that object). Without knowledge, there is no meaning for freedom.
If mind has no seat in space and time, how does it interact with “objects” in space and time?
I’d use the word “consciousness” instead of “mind”. My take on this problem is that consciousness is universal. It is the reason why space and time exist, to begin with. Take a piece of space-time in the universe, and consciousness will have to be present in it. The author of this blog uses the word “pan-psychism” or “pixies everywhere” to describe this. But I don’t want to use these words, because I’d like to highlight my position which is that consciousness is not only universal but also singular. This is best described by the word “monism”.
Comment by vakibs — September 30, 2009 @ 9:43 pm
14.
It is confussing to use the mathematical/physical concepts of determinism, that are well defined in terms of the mathematical properties of the set of differential equations we use to model a particular system, and the properties of its solutions. Then we have, deterministic systems that allow us to predict the evolution up to a certain extent, or chaotic systems in which boundary conditions require too much presion and accuracy in practical terms, therefore predictions are almost impossible, or quantum systems in which solutions are understood in terms of probability derived from the wave function. And all these concepts are well defined.
I don’t believe these concepts can be “directly” used in the free-will problem. Even if modelling the brain as a physical system, the problem is too complex too understand the decision making process in neurophysiological terms, irrespective of the nature.
If you toss a coin, wether you find head of tails, does not mean that the coin has made a decision. In a quantum system, once you measure a particular value (amongst a possible set) for a variable, does not mean that the system has “made the decision” to have that value.
Before using Libet-like experiments we should defined what kind of processes could be supporting decision making, and what do we really mean by making a decision. I believe there is a big range from compulsive actions to analytical decisions and cannot be treated in the same fashion. Free will has to terms. First, let see what do we really mean by “will”, and then if is is free or fully conditioned.
Moreover, if the free-will problem is ever solved, we would need to analyse the moral implications.
Up to what extent is a man responsible for his acts?
Comment by Vicente — October 1, 2009 @ 8:02 am
15.
If you toss a coin, whether you find head of tails, does not mean that the coin has made a decision.
No, it is not the “coin” which made the decision. But clearly a decision has been made here and a symmetry has been broken to a clearly defined outcome. If this decision is the outcome of a previously defined set of laws, then this outcome can be called deterministic. Otherwise, it will be called a “free” outcome, something that is beyond the set of laws of physics (as they are defined up till that point).
Stochastic determinacy is just a different level of looking at things. Things which are random or chaotic (like molecules in an ideal gas) usually present an order at a grander scale. My take is that the universe is not even stochastically deterministic, at any scale. There shall never be a finite (or countably infinite) set of laws that can completely define the universe (or a piece of it). This limitation is not just with respect to our current understanding of the universe, which is indeed woefully incomplete. But about the very nature of this universe.
The probabilistic nature of quantum systems need not be called non-deterministic. What is non-deterministic about quantum systems is the step where this probability is broken and where the wave function collapses into a fixed state. As we understand, this step cannot be explained today by any (countably infinite) set of physical laws. My take is that this shall forever remain so, no countably infinite set of physical laws shall *ever* describe this. This pure non-deterministic nature is the source of freedom in the universe.
It is a philosophical perspective whether you look upon this non-determinacy as due to an “agent” (in which case, these outcomes will be due to the “free-will” of that agent), or whether you look upon it as a split of the whole universe into parallel universes. I take the former perspective, because I don’t want to create a multitude of additional variables (parallel universes) to explain our current universe.
In a quantum system, once you measure a particular value (amongst a possible set) for a variable, does not mean that the system has “made the decision” to have that value.
I am not arguing about “what” made the decision about this value. But clearly, a decision has been made about this. I believe that there exists one *single* agent in this universe who makes decisions. Whether that decision is recorded in a particular physical object in this universe (whether that be the brain of a human being, or the molecular arrangement of a gas etc) is immaterial and secondary.
Up to what extent is a man responsible for his acts?
Up to the extent to which he is conscious of his decisions. In simpler words, up to the extent to which he has a recorded knowledge of his decision process (this information being stored either neurologically in the brain, or linguistically in an external region).
Comment by vakibs — October 1, 2009 @ 11:40 am