The claims by the government that the scanners deliver harmless amounts of radiation are being challenged by some scientists.
(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
Adam Savage (of the TV show Mythbusters) describes how the TSA put him through the porno scanner but later once on the plane he realized that he had in his jacket two twelve inch long steel razor blades that he had brought home from work and forgotten about. (via Balloon Juice.)
Recently, I have been receiving highly critical spam comments. Here is one typical example:
What a waste of time. You’re [sic] poor english [sic] made this article hard to read. Learn to write.
I have to admit I am puzzled by the psychology of this. One form that spam comments take is to give an effusive but generic compliment (“Your blog is great!”), presumably to flatter me so that I won’t delete it. It never works but I can understand the strategy.
But I am totally baffled by what the spammer hopes to achieve with an insult.
(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.
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?
One of the major thinkers on US foreign policy whose pre-9/11 book Blowback: The Costs and Consequences of American Empire made the concept of ‘blowback’ a key element in understanding why the US is in such a predicament, died on Saturday.
Steve Clemons reflects on his legacy. He says that Johnson started out as an establishment figure and strong supporter of the Vietnam war but later became on of the biggest and most influential critics of the drive towards creating and sustaining the American empire. As Clemons says, “Many of Johnson’s followers and Chal himself think that American democracy is lost, that the republic has been destroyed by an embrace of empire and that the American public is unaware and unconscious of the fix.”
(For previous posts in this series, see here.)
The idea suggested by Benjamin Libet that what we call free will is not the popularly assumed ability to decide all our seemingly deliberate (as opposed to instinctive) actions but consists of the more limited ability to either let the predetermined action be completed or to veto it may be unsatisfying to some but its implications are worth exploring in case it turns out to be true. What this model says is that I have no control over what I decide to do in any given situation but I do have control over whether that decision is actually carried out. In other words, I cannot control my thoughts and decisions but I can control (within a limited range) my actions.
Libet suggests that if, as he believes, our decisions to act are involuntary but the decision on whether to allow that act to be carried out or to veto it is freely arrived at, that should influence how our justice and moral systems should work.
How do our findings relate to the questions of when one may be regarded as guilty or sinful, in various religious and philosophical systems? If one experiences a conscious wish or urge to perform a socially unacceptable act, should that be regarded as a sinful event even if the urge has been vetoed and no act has occurred? Some religious systems answer ‘yes’. President Jimmy Carter admitted to having had urges to perform a lustful act. Although he did not act, he apparently still felt sinful for having experienced a lustful urge. But any such urges would be initiated and developed in the brain unconsciously, according to our findings. The mere appearance of an intention to act could not be controlled consciously; only its final consummation in a motor act could be consciously controlled. Therefore, a religious system that castigates an individual for simply having a mental intention or impulse to do something unacceptable, even when this is not acted out, would create a physiologically insurmountable moral and psychological difficulty.
Religious systems like Christianity punish people for even thought crimes, because god is apparently monitoring everyone’s thoughts all the time to check for any transgressions. But this makes no sense if we have no control over our thoughts (granting for the sake of argument that the idea of a god who can read everyone’s thoughts makes any sense at all). I am sure that if this understanding of the brain ever becomes firmly established, the ever amenable and highly flexible theologians will come up with new interpretations of their holy books to say that how they interpreted them earlier was wrong and that the correct interpretation is that thoughts alone are not sinful. This kind of theological flexibility to accommodate the latest science has been the pattern so far.
Libet argues that secular ethical systems will also have to adjust, though not as much.
Ethical systems deal with moral codes or conventions that govern how one behaves toward or interacts with other individuals; they are presumably dealing with actions, not simply with urges or intentions. Only a motor act by one person can directly impinge on the welfare of another. Since it is the performance of an act that can be consciously controlled, it should be legitimate to hold individuals guilty of and responsible for their acts.
The idea that we should only punish people for their actions and not their thoughts has implications for so-called ‘hate crimes’ legislation whereby people are punished more harshly for the same act if their actions are deemed to arise from intent to harm someone because of animosity towards their victim’s race or ethnicity or gender or sexual orientation. If what people think is beyond their control, it does not make sense to factor it in when determining punishment. (Since I already oppose hate crime legislation for other reasons, I would not be sorry to have a scientific reason to eliminate them.)
Libet makes a final plaintive plea for retaining the idea of free will by suggesting that according to the evidence, at least at the time he wrote it in 1999, believing in free will is at least as good an option as determinism, and so we should hold on to it until more conclusive evidence against it turns up.
My conclusion about free will, one genuinely free in the non-determined sense, is then that its existence is at least as good, if not a better, scientific option than is its denial by determinist theory. Given the speculative nature of both determinist and non-determinist theories, why not adopt the view that we do have free will (until some real contradictory evidence may appear, if it ever does). Such a view would at least allow us to proceed in a way that accepts and accommodates our own deep feeling that we do have free will. We would not need to view ourselves as machines that act in a manner completely controlled by the known physical laws.
Benjamin Libet died in 2007 and thus did not have to confront the results of experiments carried out the very next year that seem to provide just the kind of evidence contradicting free will that he clearly hoped would not materialize. I will discuss these in the next post in this series.
Next: Recent fMRI studies of the time sequence of decisions and actions.
Jerry Coyne has a post with photographs describing the devices used by the Catholic Church in Colombia to torture heretics into making confessions during the inquisition that lasted from 1610 to 1821. It is sickening what they did and the article is not for the squeamish.
But of course, all this was done in the service of a loving and merciful god, so it must be good, no?