Showing posts with label brain. Show all posts
Showing posts with label brain. Show all posts

Wednesday, November 26, 2014

Patience May Indicate Free Will


They say that patience is a virtue. It may also support the notion of free will. A person may defer action, as in pursuing a reward for example, because of a free choice to delay. This possibility lies at the heart of a new study in a long series of studies that began in the 1980s that have tested the notion that free will might not exist, that it is an illusion.

The prior experiments, widely interpreted to indicate that free will does not exist, demonstrated that neuron activity in  a movement-control area of the cerebral cortex accelerated prior to a conscious decision to press a button. Thus, scientists interpreted this to mean the decision was made unconsciously, prior to the conscious realization that a decision had been made. I have challenged this interpretation on both grounds of the scientific methods used and misinterpretation of the cognitive neuroscience (see manuscript at www.ac-psych.org/download.php?id=84).

In this new study, Masayoshi Murakami and colleagues in Portugal, this electrical marker of decision-making was studied in rats in a different paradigm. Highly thirsty rats were trained to wait in place after hearing a sound cue until a second sound, a "go-for-it" sound was heard that would give them access to water. If the rats showed the required restraint, they received a larger water reward.

As the rats waited, the electrical "decision-making indicator" grew in magnitude and reached a threshold at the point where rats lost patience and went for the reward. The progressive increase in neural firing is interpreted as a well-known "integrate-and-fire" mechanism, wherein activity grows until a threshold for action is reached.

But they also found a second class of neurons whose firing could predict the rate at which the integrating neurons added up toward threshold. This observation of preceding regulatory control enabled a new interpretation of the original free will experiments on illusory free will. The "integrate-and-fire" population of neurons may not be making the actual decision, but rather reflecting an earlier decision-making processes elsewhere that regulate the integration toward action threshold.

Decision-making is complicated, even when it just involves pressing a button. I try to explain all this in my new book from Prometheus, "Mental Biology. The New Science of How the Brain and Mind Relate."

Source:

Murakami M, Vicente MI, Costa GM, & Mainen ZF. (2014) Neural antecedents of self-initiated actions in secondary motor cortex. Nature Neuroscience, 17(11), 1574-82. PMID: 25262496

Friday, September 7, 2012

Are Humans Just Blameless Robots?


Ever make a really stupid decision? Or said something embarrassing? Or did something you were later ashamed of? I guess maybe we all have. Maybe you even committed a crime.

Not to worry. It’s not your fault, according to a growing body of philosophers, psychologists, and neuroscientists. These learned people tell us that humans do not make conscious intentions, decisions, or choices. Those are all made by our robotic unconscious mind, which makes its intentions, decisions, or choices known after the fact to conscious mind.

I wrote an earlier blog on this subject (http://brainblogger.com/2010/10/25/free-will-is-not-an-illusion/), but want to explore it some more because the growing acceptance of blamelessness is having serious consequences in our schools, courts, and in politics.

This idea has actually been around for a long time, apparently 2000 years according to Roskies (2010). But the modern father of the robot view was Ben Libet, who in the 1980s, performed some simple experiments that he and most others interpreted to support the robot view. Basically, he showed that brain signs of a decision to press a button appeared a fraction of a second before the experimental subject said a decision had been made―thus unconscious mind made the decision and later made conscious mind aware of it.

Actually, there are lots of flaws in this experiment and its interpretation, which were pointed out by several scholars in the succeeding years. In 2010, I summarized these objections and added some of my own in a review of the subject. My criticisms focus on three main points: 1) timing of when a free-will event occurs requires introspection, and other research shows that introspective estimates of event timing are not accurate, 2) simple finger movements may be performed without much conscious thought and certainly are not representative of the conscious decisions and choices required in high-speed conversation or situations where the unconscious mind cannot know ahead of time what to do, and 3) the brain activity  measures used were primitive and incomplete. I identified 12 categories of what I regarded as flawed thinking about free will.

Conflicting evidence was available too. Christoph Herrmann and colleagues had reported a study in which subjects were instructed to press one of two buttons, depending on the presented stimulus. They found neural activity preceding the motor response, similar to Libet's experiments. However, this activity was already present prior to stimulus presentation, and thus before participants could decide which button to press. They therefore concluded that this activity does not specifically determine behavior, but more likely reflects a general expectation or preparation for making a choice.

The major flaw in the robot theory is the assumption that conscious choice is a point process that can be quantified in fractions of one second. Yet, real-world willed actions are not instantaneous but often smeared out over long periods of time. In addition, there is overwhelming evidence of a substantial lag between when a conscious decision or choice is made and when it becomes recognized as such.

Soon after my paper, several investigators reported studies that challenged the robot view. For example, Trevena and Miller modified the Libet design to include instructing subjects to occasionally make a decision not to press the button. They saw the same antecedent brain activity irrespective of whether the decision was to move or not to move. Clearly, the antecedent brain activity is not specific to intention to move. The results do not, however, rule out the possibility that unconscious mind makes all decisions (including not to move, in this case),

So, just what does this activity prior to conscious realization represent? No one really knows. In all likelihood, it can reflect the initiation of actions consciously chosen prior to the experiment, or as I put it, consciously following the experimental protocol’s “rules of the game.”  The participants’ reported decision time may just reflect the conscious confirming recognition and re-approval of the initiated action. Sheffield and colleagues (2011) recently showed that neurons can integrate spikes over a period of minutes, slowly reaching a threshold that later produces persistent activity without any additional input.

First of all, I find it interesting that this question is even discussed by any scholars other than philosophers.  This is because free will is not a scientific question. Science requires that an idea or hypothesis has to be framed as falsifiable. Is any theory about free will really falsifiable?  I would argue that this is a metaphysical question and one for which we lack the tools to fully understand.  Like Immanuel Kant, I think we will always be blinded by the spectacles of our own human reason.

Secondly, to hold the robot view, especially on the basis of problematic evidence, is personally and socially unwise, even dangerous. And the problem is that laymen increasingly seem to embrace the position of the scholars. In such areas as education, criminal justice, and politics, personal responsibility is old fashioned, so yesterday.

Take education. Everybody recognizes that schools are in trouble. But nobody holds students and their parents responsible for poor performance. No, the blame is placed on insufficient funding, teachers, school boards, state and local government.

Take criminal justice. It is growing practice among defense attorneys to seize upon any indication of a brain dysfunction to get their client off or have a reduced sentence. Judges and juries often buy the argument. The latest science fad of brain scans has hit the courtrooms. If a scan is different from normal, that must then be reason for the crime. For example, one survey of a few murderers showed that they had abnormal brain scans. That was interpreted to explain the crimes. But nobody raised the possibility that the abnormal brain scan might have been caused by what the murder thought and did over the many years before the crime. This, despite the clearly established fact that what a person experiences, thinks, and does changes the brain structurally and chemically.

Then, there is politics. Democrats are big on “social justice” and particularly encourage people to think of themselves as members of a group that is unfairly treated.  Life is not fair, and if people can be convinced they are victims of one sort or another, politicians get votes by appealing to them as their protector. So the mantra goes like this: blacks and Hispanics are oppressed by Anglo racists, the poor by exploiting rich people, workers by greedy business owners, women by chauvinistic men, gays by homophobic straights, college students by those who set tuition rates. Everybody is encouraged to think of themselves as members of an oppressed group, bitter and envious, and in need of help from liberal politicians to get justice.

It is very comforting to believe that the adversities of life or even your own poor choices are not your fault. If you are not responsible, you get to blame something or somebody else. How convenient.

In terms of how the brain works, unconscious and conscious minds interact and share duties. Unconscious mind governs simple or well-learned tasks, like habits or ingrained prejudices, while conscious mind deals with tasks that are complex or novel, like first learning to ride a bike or play sheet music."

We do often act like robots driven by our unconscious drives when we act out of habit, prejudice, or prior conditioning. But we should and can be responsible for what we make of our brains and for the choices in life we make. In a free-will world, people can choose to extricate themselves from many kinds of misfortune―not to mention make the right choices that can prevent misfortune.

Brain activity causes other brain activity that results in intentions, decisions, choices, and assorted behaviors. Consciousness arises from and is part of brain activity. Therefore, the brain activity of consciousness can cause and modify other brain activity. People are personally responsible because they have a conscious mind with the power to program the brain and its unconscious mind.

Sources:

Herrmann, C. S. et al (2008). Analysis of a choice-reaction task yields a new interpretation of Libet’s experiments. International J. Psychophysiology. 67: 151-157.

Klemm, W. R. (2010). Free will debates: simple experiments are not so simple. Advances in Cognitive Psychology. 6: (6) 47-65.

Roskies, A. L. (2010). Why Libet’s studies don’t pose a threat to free will. In W. Sinnott-
Armstrong & L. Nadel (Eds.), Conscious will and responsibility (pp. 11-22). New York:
Oxford University Press.

Sheffield, M. E. et al. (2011). Slow integration leads to persistent action potential firing in distal axons of coupled interneurons. Nature Neuroscience, 14(2), 200-207. doi:10.1038/nn.2728

Trevena, J., and Miller, J. (2010). Brain preparation before a voluntary action: evidence against unconscious movement initiation. Consciousness and Cognition. 19 (1): 447-456.