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December 30, 2011 / compassioninpolitics

Do humans have freewill? Is the universe deterministic? Is the brain deterministic?

Michael Gazzaniga – Free Yet Determined and Constrained

Michael Gazzaniga is a Professor of Psychology and the Director for the SAGE Center for the Study of Mind at the University of California Santa Barbara.

In addition to his position in Santa Barbara, Professor Gazzaniga is also the Director of the Summer Institute in Cognitive Neuroscience, President of the Cognitive Neuroscience Institute, and is the Director of the MacArthur Law and Neuroscience Project.

This is probably on the “skeptical” side in terms of its conclusions. He speaks of the issue of downward causation (ie context/environment and social influences having an effect on our choices–which is true–the way he frames the end of the talk seems to be more determinist that I would like. But his science certainly supports choice. I wish earlier he has also pointed out the issue that deep human contemplation before an action could also possibly trigger false indications of determinism. Alfred Mele Professor of Philosophy at the Florida State University explains it better when asked this question:

Question: What are the mistakes?

Alfred Mele: Okay, it is an interesting result, but what does it really show? Do we know that it’s decisions that are being made at -550 milliseconds, that is about half a second before the muscle burst, as opposed to something else? Well, one thing it could be instead of decisions is a causal process is up and running that increases the probability of a subsequent flexing, but doesn’t raise it to one. So, what you might have then at -550 is a potential cause of a subsequent flexing. And the decision might be made later than -500 or -550. It might even be made around -200, when people say they think they made it. So, that’s one problem, we can’t really correlate this early spike with the decision at that time. And in fact, the way the study is done is what triggered the computer to make a record of the preceding second, or more, of brain activity was the muscle burst. So, there is a muscle burst, and that triggers the computer, okay, make a record of this preceding second of brain activity. But if you use that methodology then you never looked for cases where you get this spike about half a second before, call it zero time, but no muscle motion. You don’t because it’s the muscle motion that triggers the computer to make a record of the preceding activity.

So that’s one problem. And one thing you might wonder too is, so how long does it take a decision to flex your wrist now to generate a muscle burst, or a wrist flexing. And there’s a way to get indirect evidence about that. You could give subjects a reaction time test. So now they wouldn’t be making the decision, but they would be responding to a queue with an intention. So the task might be flexing your wrist whenever that clock changes color from red to green. Okay? And they could be watching the clock too. And it turns out that reaction time studies have been done with a Libet clock. And a mean reaction time, in one study anyway, was 231 milliseconds. There was just a 231-millisecond gap between the emission of the go signal, which was a sound in that study, and the muscle burst. But if it took an intention or a decision something like 550 milliseconds to cause a muscle burst, this result would be very surprising. I mean, here it’s only roughly 200. And of course after there is the go signal, it’s going to take some time to respond mentally with an intention. It doesn’t have to be a conscious intention, but it’s a causal process, so it takes time.

So, that’s another problem. And then there’s a third problem with these studies and it has to do with the measurement of awareness. So, after they flex again, subject moved the cursor to the spot and say that’s when I first became aware of it.

Question: How does measurement of awareness become a problem?

Alfred Mele: So, it must have been two-and-a-half to three years ago now that I gave a lecture on the neuroscience of free will at the National Institute of Health in a motor control unit. The idea was, I do my lecture and then after that they make me a subject in one of these Libet experiments, which was cool. I was interested. And then after that I got out to dinner. They take me out to dinner, but first I have to be a subject in the experiment. So, I gave my lecture then it was time to do the experiment. I was sitting at the chair, they set up the clock and I knew what my task was. And I wanted to pretend to be a naive subject. I wanted to put myself in the shoes of somebody who might do this and not really knowing what is going on. And so, I thought this is what I’ll do, I’ll sit there and watch the clock and I’ll wait for urges to flex my wrist to pop up in me to become conscious, and then as soon as I have such an urge, I’ll flex and then after I flex I’ll move the cursor to where I thought the spot was on the clock when I first became aware of that urge, or intention, or whatever.

So, I was sitting there a little while and nothing was happening. That is, no urges was coming to mind. And I thought, how did they do this? How do these people do it? And then I thought, I better think of a way to do it because otherwise I’m going to be stuck in this chair and I won’t get any dinner. Right? Dinner was next. So, I thought, this is what I’ll do. I’ll just consciously say “now” to myself silently and treat that as an indicator of an urge or a decision, and then I’ll flex and then after I flex, I’ll report where the spot was on the clock when I said “now” to myself.

Okay. So, I had to remember to do this then. Say “now,” flex as soon as possible after I say “now,” and then do the reporting. And at first the neuroscientist said I was flexing in too wimpy a way, so I had to remember to flex hard too. So, okay. I did all of that. And these experiments subjects had to do at least 40 times to get data you could actually read and use. So, I did it about 40 times. And one thing I discovered that although I could pinpoint the spot on the clock to maybe a range of the clock, I don’t know, 20%, 25% of the clock. I couldn’t pinpoint it to an exact tick, let’s say. That was one problem. Also, I had something every definite to look for internally. I was looking for the conscious “now” saying, and I know what that’s like. But subjects who are said, who are instructed to look for an urge or an intention, or decision, or whatever, might wonder, “Well, what the heck was that that I was just experiencing? Was I just thinking about doing it, was it an urge?” So, there could be confusion that they would have that I didn’t have.

Question: What is the bottom line of these experiments in terms of where we stand on that free will scale?

Alfred Mele: Well, these experiments are thought to show that there is no free will. And my main point here is, they don’t show that. For three different reasons really. These judgment times are unreliable, so we don’t really know when people first became aware of the urge. And we don’t have good evidence of what happens at -550 milliseconds, about half a second before the muscle burst, is that a decision is made as opposed to a potential cause of a decision is present. And we don’t have evidence that what’s happening half a second before the muscle burst is sufficient for subsequent muscle bursts. So, it just leaves free will wide open.

Another thing too is, notice what we’re studying here. We’re studying relatively trivial actions. Wrist flexions or mouse button clickings and decisions to do things now. And it may be that free will mainly isn’t at work in that dimension in our lives, but mainly is at work in broader dimensions when we’re thinking about maybe back to students they’ve been accepted into different graduate schools with different scholarship offers and they are thinking about which one to take. Or, maybe thinking about whether to propose marriage, or not, or whether it’s time finally to get the divorce or what house to buy. You know? It maybe that free will is more involved in things like that then in wrist flexions and the like. And then, now this is not a criticism of the scientists who do this work, but with the technology we have now, if you’re going to be studying something similar to free will, it looks like you’re going to be in this domain and not the domain of choosing graduate schools, buying houses, proposing marriage.


Roskies, Adina L., How Does Neuroscience Affect Our Conception Of Volition?, 33 ANN. REV. OF NEUROSCIENCES 33 (2010). (its available here)

(Other possible link)

(Even Bertrand Russell’s well known critique of the notion of causation, published in 1912: Russell, B., “On the Notion of Cause,” Proceedings of the Aristotelian Society, 13: 1–26.) This might also have some value:

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