The coming death of the idea of free will

The idea of human beings having free will is so powerful that it would seem to be impossible to dislodge. Having free will seems to be so essential to the way that we view ourselves that denying its existence seems like denying our very humanity, transforming ourselves into mindless automatons, and thus we are loathe to relinquish it. Isaac Beshevis Singer captured this struggle well when he said, “We must believe in free will. We have no choice.” [Read more...]

Update on free will

Readers may recall my multi-part series on free will in which, among other things, I reported on the pioneering 1983 experiments of Benjamin Libet. Peter Hankins reviews a recent paper that uses latest developments that have been made possible by more recent sophisticated technology that can look at the activity of individual neurons in the brain. The researchers get results that essentially validate Libet’s conclusions and provide further insights. Hankins explains what it might all mean.

On free will-16: A sense of self in the absence of free will

(For previous posts in this series, see here.)

According to the writer Isaac Beshevis Singer, “We must believe in free will, we have no choice.” It is a funny line because of its paradoxical nature and yet also profound because of its multiple layers of meaning. On the one hand, it could be interpreted as saying that belief in free will is likely hardwired in our brains and we are thus compelled to believe in it, whether it is true or not. On the other, it implies that the idea of free will is so important to our sense of self as autonomous agents and to the way that our society is organized that even if we realize it is a fiction, it is a fiction that we must adopt because to abandon it might lead to cognitive confusion and social disarray. This series of posts has tried to show that this fear is unwarranted and in this, the last post, I want to address the issue of what it all means for our sense of self.

Does the lack of free will mean that I am an automaton, simply obeying the laws of physics, chemistry, and biology, and that my sense that ‘I’ am controlling my actions is an illusion? If by ‘I’ we mean an autonomous agent that acts independently of the body, then yes, that is an illusion. But what we mean by ‘I’ is more complex than that. As several alert readers have pointed out, even though this series of posts has argued that free will as traditionally conceived does not seem to exist, I have made statements that suggest that I am dependent on the concept, writing things like, ‘This may also explain why it is so hard to change the way we are used to doing things and the importance of developing good habits early.” As one emailer astutely pointed out, “If there is no free will how do you ‘change’ or ‘develop’?”

As another example, I wrote that there is benefit to society punishing crimes as a means of deterring future crimes. But this implies that society is making a choice of one policy over another. Who exactly is doing this choosing and what does it mean in the absence of free will? Similarly, while we can understand why devoting hours to practicing tennis can create brain networks that make good choices of play automatic, what was behind the decision by expert players to ‘choose’ to devote so much time to this kind of activity in the first place? Was that choice also predetermined?

Such questions go to the heart of our misgivings about the lack of free will.

Part of the problem is that our language is so immersed in the idea of free will that it is hard to avoid the kind verbal ditches that I appear to have plunged headlong into. Trying to carefully formulate sentences to avoid the impression of acting out of free will leads to convoluted language. Fortunately for us, as I said in the previous post, for most practical purposes, we can continue to act and speak as if there is free will without it creating any operational differences that we can detect, at least at a coarse, everyday level. One needs to go into the laboratory to see these effects.

But before we can agree to continue to use the language developed around the fiction of free will because it is familiar and simpler, we have to come to a consensus on what it really means, in the absence of free will, to say that ‘I’ ‘decide’ or ‘choose’ to do one thing instead of another.

Steven Pinker (The Blank Slate, p. 174) tries to clarify this point:

In the traditional conception of a ghost in the machine, our bodies are inhabited by a self or a soul that chooses the behavior to be executed by the body. These choices are not compelled by some prior physical event, like one billiard ball smacking into another and sending it into a corner pocket. The idea that our behavior is caused by the physiological activity of a genetically shaped brain would seem to refute the traditional view. It would make our behavior an automatic consequence of molecules in motion and leave no room for an uncaused behavior-chooser.

One fear of determinism is a gaping existential anxiety: that deep down we are not in control of our own choices. All our brooding and agonizing over the right thing to do is pointless, it would seem, because everything has already been preordained by the state of our brains. If you suffer from this anxiety, I suggest the following experiment. For the next few days, don’t bother deliberating over your actions. It’s a waste of time, after all; they have already been determined. Shoot from the hip, live for the moment, and if it feels good do it. No, I am not seriously suggesting that you try this! But a moment’s reflection on what would happen if you did try to give up making decisions should serve as a Valium for the existential anxiety. The experience of choosing is not a fiction, regardless of how the brain works. It is a real neural process, with the obvious function of selecting behavior according to its foreseeable consequences. It responds to information from the senses, including the exhortations of other people. You cannot step outside it or let it go on without you because it is you. If the most ironclad form of determinism is real, you could not do anything about it anyway, because your anxiety about determinism, and how you would deal with it, would also be determined. It is the existential fear of determinism that is the real waste of time. (Boldface emphasis is mine.)

The lack of free will in the traditional sense need not mean we are diminished somehow, unless our sense of self is totally intertwined with a belief in the existence of a ghost in the machine. Who we are and what we do are the products of our personal and evolutionary histories, along with some randomness thrown in along the way, all completely subject to the laws of nature. All these combine to make us unique and react in individual ways to the situations we encounter. The unconscious brain is not some kind of alien despot making ‘us’ (i.e., the conscious brain) slaves to its bidding whether we want to or not. The unconscious brain is as much truly us as the conscious brain and to the extent that we use the locution of it ‘making’ us do things, those things are completely consistent with who we are.

When we ‘choose’ one option over another, our brain really does go through the process of weighing all the options and consequences before arriving at a verdict and issuing a command to our motor neurons to execute an action. The fact that all this processing of information takes place behind a screen that is opaque to us, and that our conscious brain becomes aware of it only after the decision has been made, does not alter the fact that ‘we’ made the decision.

Our bodies and our minds, our actions and our thoughts, are all part of one internally consistent biological system. The many parts of our brain are working all the time, performing all their functions in concert with one another. The fact that we are aware of only the conscious part of it, and that this part may not be the instigator or driver of our actions, should only be disconcerting to those who wish to assign pride of place to the conscious brain and give it qualities of uncaused autonomy that it does not have.

We should view ourselves as a stage play that is unfolding. The stage setting and the actors are like the conscious brain, the things that we see and are aware of, but the performance also requires the participation behind the scenes of many unseen groups like the lighting crew, the sound crew, and the stage hands, all obeying the instructions of the director and the playwright, the last two items in this metaphor representing the laws of science. In a successful production of a play, each component system behaves in concert with all the other systems of the production to create an integrated experience. It does not detract from our enjoyment that the actors are not truly ‘free’ to say and do what they wish, because the play is all of one piece and for them to act independently in that way would result in incoherence and confusion. During a good performance we forget that the actors are playing predetermined roles and view them as responding spontaneously to their surroundings, even though we know deep down that this is not the case.

We should enjoy our lives and ourselves in the same way.

Bibliography

In preparing and writing this series of posts on free will, in addition to the journal articles and news reports that were linked to, the following books were explicitly quoted or referred to.

  • Steven Pinker, The Blank Slate: The Modern Denial of Human Nature, Penguin, 2002

  • Daniel C. Dennett, Consciousness Explained, Little, Brown, & Co., 1991
  • Rene Descartes, Meditations and Other Metaphysical Writings, Translated by Desmond M. Clarke, Penguin Classics, 1998

The following books, while not directly used, provided me with general background information about how the brain works.

  • Douglas R. Hofstadter, Godel, Escher, Bach: An Eternal Golden Braid, Basic Books, 1980

  • Roger Penrose, The Emperor’s New Mind: Concerning Computers, Minds, and the Laws of Physics, Oxford University Press, 1989
  • Steven Pinker, How the Mind Works, W. W. Norton, 1997
  • Daniel C. Dennett, Darwin’s Dangerous Idea: Evolution and the Meaning of Life, Simon & Schuster, 1995
  • Antonio Damasio, Descartes’ Error: Emotion, Reason, and the Human Brain, Avon Books, 1994

On free will-15: Acting as if there is free will

(For previous posts in this series, see here.)

Let’s consider two scenarios. In one case, John carefully plans and executes a murder. In the other case, Susan kills an assailant who attacks her. With a belief in free will, we assume that John freely made a willful and conscious decision to commit that act and is thus more culpable than Susan who reacted on the spur of the moment out of the instinct for self-preservation and thus did not use her free will. We thus feel justified in punishing John more harshly than Susan.

If there is no free will, that means that both John’s and Susan’s actions were the result of unconscious neural activity, the only difference being that John’s neural activity had sufficient lead time to create conscious thoughts. Shouldn’t the planned murder be treated in the same way as the self-defense? Doesn’t that imply that they should be punished the same? Is this fair?

No, we don’t have to punish them equally because the idea of fairness is determined by the rules that society has set for itself in order to function in an orderly manner. We may concede that in the absence of free will, the murderer who carefully planned his actions is no worse morally than the person who killed in self-defense, because both actions were the product of unconscious neural activity, but that does not preclude us from punishing them differently in order to achieve society’s purposes. Since the purpose of punishment is deterrence and deterrence is presumed to work whether we have free will or not, it makes sense for us to punish John more harshly in order to deter others from committing premeditated murder.

As a practical matter, the lack of free will may be buried so deep that we agree to run our lives and societies on the assumption that people are responsible for their actions, i.e., as if free will exists. As Steven Pinker says, (The Blank Slate, p. 180) “Most philosophers believe that unless a person was literally coerced (that is, someone held a gun to his head), we should consider his actions to have been freely chosen, even if they were caused by events inside his skull.”

In fact, in terms of our everyday practical lives, a society that believes in the fiction of free will be almost indistinguishable from one that does not. The complexity and unpredictability of human behavior is sufficient for us to continue to treat free will as the proximate basis on which we make decisions, even if there is no free will at the ultimate neural level.

Deciding to organize society on the basis of treating people as if they have free will even if we know they haven’t may sound odd but that kind of arrangement is not unusual. We do it all the time. For example, we manufacture all kinds of excuses for carefully planned murders to avoid punishing the killers. When the state executes prisoners, it is carrying out a carefully planned murder. No one would argue that it was done instinctively in self-defense or that we are not aware of what we are doing. But we excuse such murders. When countries go to war, they carefully plan and murder thousands of people, many of them totally innocent of any wrongdoing. Society has agreed to treat such murders as if they are not murders.

But there is a huge difference between truly believing in a fiction like free will and knowing that it is merely a convenient fiction. In the former case, it drives the way we think about things and can thus lead to erroneous policies, while in the latter case, the idea of free will does not form the basis for policymaking and the details of the fiction can be adjusted if necessary to conform to the needs of reality.

In fact the case can be made that the traditional notion of free will, that of an independently existing mind or soul that could truly act freely would, if true, be more dangerous to society because such an entity would not care what happened to the body and thus could command the body to do whatever it likes irrespective of the consequences. In fact, this is what drives religious fanatics who commit atrocities. They believe that their souls or spirits or whatever they call this independent entity that they consider their ‘true’ selves will not only survive their bodies’ demise, it will even reap rewards for their suicidal actions. It is such people who can be so cavalier about taking personal risks in their quest to harm others. A person who believes that the body and mind are merely different aspects of a single biological entity, and that the death of the former will result in the simultaneous disappearance of the latter, is far more likely to want to preserve the body and so act more prudently.

So the concept of free will, in addition to being unsustainable scientifically, is also undesirable as a practical matter. It is time to give it up.

Next: The unwarranted fear of determinism

On free will-14: Misuse of the insanity defense

(For previous posts in this series, see here.)

Many people are suspicious of the insanity defense, suspecting that it is abused by unscrupulous criminals and their lawyers. The fact that psychiatrists and other experts can be found to argue both sides of the case adds weight to the suspicion that there is no objective basis to many of the claims of insanity.

This problem arose when the grounds for the insanity defense was loosened from the strict M’Naghten rule. In a 1954 court decision Durham vs. United States, a US Appeals Court extended the reach of the insanity defense beyond cognitive incapacity and said that “The rule we now hold is simply that the accused is not criminally responsible if his unlawful act was the product of mental disease or mental defect.” (Steven Pinker, The Blank Slate, p. 184) As a result of the Durham precedent, there was a proliferation of expert testimony on both sides to argue the question of whether the accused did in fact have a mental disease or defect and whether the act that was committed was the product of that defective mental state, and thus not truly ‘free’.

The Durham standard is grounded in the idea of free will and assumes that in general everyone has free will to choose between right and wrong but for some people their brain defects prevent them from being able to make such choices. If it can be shown that someone’s actions are due to compulsions beyond their control, then they should not be held responsible for their actions since their will was not free. For example, lawyers in defense cases may sometimes concede that their clients did commit the crime and were aware that it was wrong (thus failing to meet the M’Naghten threshold), but they should not be held responsible because the ultimate cause of their action lay in childhood abuse or addiction to drugs or alcohol or violence in the media or rock music or pornography or the pressures of society at large, resulting in them having a defective mental state. Since it was this defective mental state that caused them to act in this way, it is argued that they were not acting freely and thus should not be held responsible for their actions.

One consequence of the understanding that there is no such thing as free will and that the purpose of punishment is deterrence and not moral judgment is that mental ‘defects’ by themselves (whatever their cause) are not sufficient to absolve people of responsibility for their actions, because every criminal act is always due to that person’s brain being different from the norm, and thus defective in some way. As Pinker says (p. 184), “Unless one believes that ordinary acts are chosen by a ghost in the machine, all acts are products of cognitive and emotional systems in the brain. Criminal acts are relatively rare – if everyone in a defendant’s shoes acted as he did, the law against what he did would be repealed – so heinous acts will often be products of a brain system that is in some way different from the norm, and the behavior can be construed as “a product of mental disease or mental defect:’” Hence the mere fact of a brain defect being the cause of an act should not be a defense.

The problem with the Durham rule is that, as a result of belief in free will, it mixes up explanation with exculpation. If we give up on the idea of free will, the legal process actually gets simpler. As Anthony Cashmore says, “psychiatrists and other experts on human behavior should be eliminated from the initial judicial proceedings—the role of the jury would be to simply determine whether or not the defendant was guilty of committing the crime; the mental state of the defendant would play no part in this decision. However, if a defendant were found guilty, then a court-appointed panel of experts would play a role in advising on matters of punishment and treatment.” Pinker adds:

And this explains why the usual exemptions from responsibility should not be granted to all males or all abuse victims or all of humanity, even when we think we can explain what led them to act as they did. The explanations may help us understand the parts of the brain that made a behavior tempting, but they say nothing about the other parts of the brain (primarily in the prefrontal cortex) that could have inhibited the behavior by anticipating how the community would respond to it. We are that community, and our major lever of influence consists in appealing to that inhibitory brain system. Why should we discard our lever on the system for inhibition just because we are coming to understand the system for temptation? If you believe we shouldn’t, that is enough to hold people responsible for their actions – without appealing to a will, a soul, a self, or any other ghost in the machine. (p. 183)

When we punish people for crimes, it should be solely for the purpose of deterring them and others from committing those same crimes in the future. The idea of punishment as a deterrent to crime makes sense even in the absence of free will but to be effective as such, punishments must be applied consistently. As Justice Oliver Wendell Holmes said (Pinker, p. 181), “If I were having a philosophical talk with a man I was going to have hanged (or electrocuted) I should say, ‘I don’t doubt that your act was inevitable for you but to make it more avoidable by others we propose to sacrifice you to the common good. You may regard yourself as a soldier dying for your country if you like. But the law must keep its promises.’ ” Note that while this example deals with capital punishment (which I oppose), the general sentiment of punishment as a deterrence applies to any form of it.

So giving up on the idea of free will, rather than making crimes less punishable as people fear, actually makes it harder to escape punishment because it applies it more uniformly and consistently. “The devil (or god) made me do it” would not be a defense unless the perpetrator’s brain was such that he or she did not know the difference between right and wrong.

So what would we do with people who commit crimes but who, under the M’Naghten rule, are deemed to have a cognitive capacity that is so impaired that they cannot judge the difference between right and wrong and so the sole purpose of punishment, that of deterrence, will not work? “Even for those who are completely undeterrable, because of frontal-lobe damage, genes for psychopathy, or any other putative cause, we do not have to allow lawyers to loose them on the rest of us. We already have a mechanism for those likely to harm themselves or others but who do not respond to the carrots and sticks of the criminal justice system: involuntary civil commitment, in which we trade off some guarantees of civil liberties against the security of being protected from likely predators.” (Pinker, p. 185)

In the next post in this series, I will look at the broader implications for the lack of free will. But for the moment, the following clip has an interesting discussion involving cognitive scientists and lawyers on the implications of neuroscience and the new understanding of the lack of free will for the law (via Machines Like Us).

On free will-13: Dealing with the consequences of not having free will

(For previous posts in this series, see here.)

It is time to examine the consequences if we are forced to conclude, as seems likely, that there is no such thing as free will and that our actions are determined by the unconscious neural activity of a physical brain that was itself the creation of the genes, environment, and stochastic processes that make up our personal and evolutionary history.

The most obvious implications lie in the areas of crime and punishment and personal morality. Does the absence of free will mean that we are condemned to an amoral anarchy, in which people can claim that they are not responsible for any and every action because they did not freely choose to do so, and thus should bear no consequences?

Actually, no. In chapter 10 The Fear of Determinism in his book The Blank State: The Modern Denial of Human Nature, Steven Pinker argues that we need not perpetuate the fiction that there is free will when there is none simply because of fears of such an outcome. Apart from the fact that it is almost always better to base our policies on what is true than on illusions, the lack of free will can actually be more effective than having it because it enables us to see more clearly when and how to assign responsibility for actions.

Take first the question of crime and punishment. Even in the absence of free will, punishment for committing a crime still makes sense because it has the effect of deterring future crimes by both the perpetrator of the crime and by other aspiring criminals who observe the culprit being punished and know that they will be punished similarly. Whether this deterrence is achieved via the product of unconscious neural network activity or a free will making a conscious decision is of no practical consequence. What the elimination of free will does is remove the element of moral judgment from punishment. The sole reason for punishing people is to deter the commission of future crimes, not to make moral statements about the culprit’s character or to seek retribution and vengeance.

The only reason for the mitigation of punishment is if the perpetrator’s brain system is incapable of responding to deterrence. As Pinker says (p. 183), “We don’t punish those who were unaware that their acts would lead to harm, because such a policy would do nothing to prevent similar acts by them or by others in the future… We don’t apply criminal punishment to the delirious, the insane, small children, animals, or inanimate objects, because we judge that they – and entities similar to them – lack the cognitive apparatus that could be informed of the policy and could inhibit behavior accordingly. We exempt these entities from responsibility not because they follow predictable laws of biology while everyone else follows mysterious not-laws of free will. We exempt them because, unlike most adults, they lack a functioning brain system that can respond to public contingencies of punishment.”

Right now we assume that people are responsible for their actions unless they are considered incapable of distinguishing between right and wrong, which is why we do not make moral judgments on the actions of infants, animals, etc. In the legal arena, the guidelines for absolving someone for responsibility were for a long time largely based on the M’Naghten rule, named after Daniel M’Naghten who, in 1843, wanted to kill the British prime minister but killed his secretary instead. He seemed to be what we would now call a paranoid schizophrenic and he was found not guilty of murder on the grounds of insanity.

This verdict caused general concern that people might invoke this kind of plea too freely as a means of escaping punishment, and in response the House of Lords drafted the following rule named after him to standardize the grounds for future claims of insanity: “Every man is to be presumed to be sane, and … that to establish a defense on the ground of insanity, it must be clearly proved that, at the time of the committing of the act, the party accused was laboring under such a defect of reason, from disease of mind, and not to know the nature and quality of the act he was doing; or if he did know it, that he did not know he was doing what was wrong.”

The M’Naghten rule focuses on the cognitive awareness of right and wrong and is quite a stringent test. The only reason to not punish a wrong action is if the person could not have been deterred by the thought of punishment in the first place because their brain was incapable of making the kinds of judgments involved. As Pinker says (p. 184), “If someone is too addled to know that an act would harm someone, he cannot be inhibited by the injunction “Don’t harm people, or else!” The M’Naghten rule aims to forgo spiteful punishment-retribution that harms the perpetrator with no hope of deterring him or people similar to him.” If everyone knows that that the lack of cognitive awareness is the sole reason for exculpation, then the deterrent effect of punishment is still strong. The only people who would not be deterred are those whose brains are similarly addled.

The rules for mitigation have sometimes been expanded to include cases where the person did know the difference between right and wrong but was unable to control their impulses or was coerced. For example, we believe that the instinct to survive is so strong that if we are faced with a deadly threat we may kill the attacker before they can kill us, even though we know that killing is wrong and that we may face punishment. The law recognizes that in such cases, we are not really making a free choice, but that we are acting on instinct, and so we have the self-defense argument. The cases of coercion are somewhat easier to adjudicate. If someone is forced to do something at the point of a gun, we view the action with leniency.

More complicated are the so-called ‘crimes of passion’ in which some acts occur because of emotions so strong that even if the perpetrator knows the action is wrong, they carry it out anyway. The ‘police officer at the elbow’ test (i.e., would the person still have committed the act even if a police officer was in the immediate vicinity) could be used to make such discriminations.

Where we run into problems is when too broad a view of brain science is taken in adjudicating crimes. Belief in free will actually creates more problems in determining who should be punished and for what, as I will discuss in the next post.

On free will-12: How about quick decisions?

(For previous posts in this series, see here.)

The 2008 research findings of Soon et. al., gave the surprising result that when we are allowed time to make decisions, our subconscious neural networks make the decisions up to ten seconds before we are consciously aware of it.

Of course, there are many situations in which we act without seeming to make any conscious decisions at all. If an object is suddenly thrown at us, we may duck, dodge, deflect, hit, or catch it, the ‘choice’ seemingly being made in much less than a second. In such cases, the action seems involuntary and we assign it to instinct, which is just another name for the unconscious neural activity of our brains. The instinct to duck when an object is directed at our head or to withdraw our hands from a hot object is due to the neural system having developed shortcuts because of its obvious survival value and has been selected for over a long time in our evolutionary history. The part of the brain that codes instincts must necessarily act very quickly to give commands to the motor brain in response to stimuli from the environment. Certain stimuli trigger a stimulus-action connection that bypasses those sections of the brain that indulge in time-consuming activities such as processing information and making judgments.

It is almost impossible to avoid, for example, even flinching when an object comes close to our eyes. Some people can do so after much practice, suggesting that they have over time developed new neural networks that can override their original instinct to create a new instinct that responds this way to specific stimuli.

But what about the case of (say) a tennis player who, seeing the ball come directly towards her over the net, seems to consciously choose in an instant whether to hit a forehand or backhand, return the ball cross-court or down the line, hit it short or deep? In this case, there seems to be a conscious decision being made and carried out, though the time available is a fraction of a second. It is such things that give us such a firm conviction that there is some part of us that is freely and consciously deciding things. How can we explain such decisions in the absence of free will?

I have not yet been able to track down studies on this particular question of brain activity for quick responses, so what I am going to suggest is pure speculation on my part, starting from the assumption that there is no free will.

The only way I can think of to explain how the tennis player’s responds is that when the ball is hit to her, the E (environment) part of the Genetics (G)-Environment (E)-Stochastic (S) model of the brain is triggered, which sets in motion a predetermined response. The unconscious neural network that decides what command to give the motor brain also sends a signal to our conscious thoughts/will that arrives there a fraction of an instant before the motor action is carried out. The fact that the conscious thought occurs before the action gives us the sense that the former caused the latter, when in actual fact both are the products of unconscious neural network activity in response to external stimuli.

This model might suggest that a tennis player will do the same thing in each situation, making their play highly predictable. In fact, there is considerable predictability in the way that athletes respond to game situations. There is a huge industry in professional sports devoted to analyzing individual players to detect patterns of their play so that their opponents can predict what the player will do in a response to a given situation and devise countermeasures.

But an expert tennis player does seem on occasion to be able to vary her shots to catch her opponent off-guard by doing the unexpected. This could be due to the fact that the stimuli they are responding to, though they may appear to be identical at a coarse level of observation, are not really exactly the same and thus cause different responses due to tiny variations. It may also be the case that there is a unpredictable element in the workings of the neural network (what I have referred to as stochastic processes) that sometimes cause her to go cross-court one time, and down the line the next, with the appropriate conscious thought being created just before the act takes place.

If this is the case, then that means that all the time when we think we are making quick decisions and acting on them, such as when we are driving, making conversation, playing sports, and so on, we are actually responding instinctively, the only difference from pure instinct (such as ducking to avoid an object coming towards our head) is that there is enough elapsed time between the decision made by our subconscious brain and the action for the subconscious brain to send a signal to our conscious brain just before the action is taken, giving us the illusion of being in control and consciously making decisions.

The part of the brain that makes quick decisions acts very much like instinct in terms of both the speed of the response and the involuntary nature of the act, except that ‘true’ instinctive responses have been hardwired into our brains over a long period of evolutionary time and we acquire them via our genes, while these quick decision responses are due to neural networks that we create over our own lifetimes and are unique to us.

Studies show that to become really competent at any skill or profession or sport (such as tennis), it takes about ten years of sustained practice. Perhaps that is how long it takes for a brain to develop the full range of synapses that enables it to respond with a range of subtle and sophisticated reactions to a wide variety of external stimuli. It is this variety of responses that gives us the illusion that we are making deliberate choices about how to respond to the current situation, rather than simply reacting based on our past experiences.

For example, when we learn to drive, we have to pay attention to road signs, to other cars and pedestrians, and be aware of the need, before changing lanes, to check the read view mirror, the side mirror, look over the shoulder for the blind spot, signal, then turn the wheel, and so on. For the novice driver, keeping all these things in the conscious mind makes driving nerve wracking, and every decision seems to take ages. I remember when learning to drive that I was mentally exhausted at the end of even a short practice session. But after much experience, we do all these things quickly and ‘without thinking’ which means that we have developed the appropriate neural networks that spring into action and provides the appropriate pre-determined response depending on the need.

It is not that we are not thinking about driving (or playing tennis) but have developed our own neural networks that enable us to think at a higher conceptual level, rather than at the level of the individual steps. So when we drive, the higher conceptual category of ‘change lanes’ triggers those neural networks that carry out all the required actions automatically. This may also explain why it is so hard to change the way we are used to doing things and the importance of developing good habits early.

Next in the series: Dealing with the consequences of not having free will

On free will-11: Recent fMRI studies of the brain

(For previous posts in this series, see here.)

In a recent paper (Unconscious determinants of free decisions in the human brain, Chun Siong Soon, Marcel Brass, Hans-Jochen Heinze, & John-Dylan Haynes, Nature Neuroscience, vol. 11, no. 5, May 2008, 543-545), researchers used the more sophisticated modern technique of fMRI (functional magnetic resonance imaging) to measure brain activity. The paper is not available online without a subscription but you can read a news report on the results of their paper here.

This experiment was designed to meet two key concerns about the Libet studies: that the time interval between act and the precursor unconscious brain activity prior to act was too small to definitively rule out measurement errors, and that Libet’s team had not shown that the early brain activity was a predictor of a specific decision.

The fMRI studies find that our decisions as to what actions we will take originate in our unconscious neural activity and only later informs our conscious mind of it, thus providing strong evidence against the existence of free will. The paper describes what the researchers asked their test subjects to do while they were hooked up to fMRI measuring devices.

The subjects were asked to relax while fixating on the center of the screen where a stream of letters was presented. At some point, when they felt the urge to do so, they were to freely decide between one of two buttons, operated by the left and right index fingers, and press it immediately. In parallel, they should remember the letter presented when their motor decision was consciously made. After subjects pressed their freely chosen response button, a ‘response mapping’ screen with four choices appeared. The subjects indicated when they had made their motor decision by selecting the corresponding letter with a second button press. After a delay, the letter stream started again and a new trial began.

Each letter was shown on the screen for 500 ms before switching to a new one and this was the time marker used by the researchers to determine when the decision to push a button was made. Note that in this experiment there are two decisions involved: when to push a button and which button to push. The fMRI data enabled the researchers to use sophisticated decoding computer programs to detect predictive signal patterns in brain activity, even in the absence of an overall increased signal strength, the latter being what the earlier experiments had depended upon. This enabled the detection of far more subtle effects.

In the trials it turned out that patients pushed both left and right buttons equally often and they were conscious of the decision to press within a time interval of one second before actually pressing a button.

But it is the other results of the experiment that are dramatic. Soon et. al. found that there was precursor activity in regions of the brain other than the SMA regions probed by Libet, and that this activity occurred much earlier than the SMA activity. Furthermore, this activity also predicted which button was going to be pushed.

[T]wo specific regions in the frontal and parietal cortex of the human brain had considerable information that predicted the outcome of a motor decision the subject had not yet consciously made. This suggests that when the subject’s decision reached awareness it had been influenced by unconscious brain activity for up to 10 s. (my italics)

Notably, the lead times are too long to be explained by any timing inaccuracies in reporting the onset of awareness, which was a major criticism of previous studies. The temporal ordering of information suggests a tentative causal model of information flow, where the earliest unconscious precursors of the motor decision originated in frontopolar cortex, from where they influenced the buildup of decision-related information in the precuneus and later in SMA, where it remained unconscious for up to a few seconds.

This figure shows the time sequence of events that the study revealed.

mind_decision_630px.jpg

The earliest precursors of an action lie in regions of the brain other than the SMA, which is the region that caused the electrophysiological effects that Libet was measuring, which explains why Libet (and Grey Walter before him) got just a half-second lead time while now it is a whopping 10 seconds. The new fMRI studies also enabled the researchers to determine that the leading brain activity selectively predicted the outcome of the subject’s choice of which button to push, and was not simply indicative of some nonspecific preparatory processes, which was the criticism made by Trevenna and Miller of the Libet team’s experiments.

They also found that the decision to push a button could be predicted up to five seconds before the act, and this information was present in the SMA and pre-SMA regions of the brain.

In this video clip, Marcus Du Sautoy records his experience of participating in this same experiment. (Incidentally, Du Sautoy, Professor of Mathematics at the University of Oxford, is the successor to Richard Dawkins as holder of the Simonyi Professorship for the Public Understanding of Science.)

Note that the predictions of which button to push were not perfect, with only around 60% accuracy. The absence of 100% accuracy is probably due to the lack of precision of the detecting apparatus and inadequacies of the pattern-recognition software, both of which are bound to get more sophisticated with time, thus increasing the accuracy of predictions. But the fact that the result is better than chance means that, as lead author Haynes says, “there’s not very much space for operation of free will” because “[t]he outcome of a decision is shaped very strongly by brain activity much earlier than the point in time when you feel to be making a decision.” Other researchers concur.

Dick Passingham, a cognitive neuroscientist at the University of Oxford in the U.K., says the paper clears up one of the major concerns about the original Libet experiment. “This activity that occurs earlier is … not just general preparation, it really is a proper decision,” he says.

Neurologist Mark Hallett of the U.S. National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, says the study confirms his understanding of free will as a perception rather than a driving force.

This seems to pretty much kill the idea of free will as traditionally understood. As biologist Anthony Cashmore says, “The reality is, not only do we have no more free will than a fly or a bacterium, in actuality we have no more free will than a bowl of sugar. The laws of nature are uniform throughout, and these laws do not accommodate the concept of free will.”

The Ghost in the Machine seems to be well and truly exorcised.

Next: What about quick decisions?