Benjamin Libet: We live 1/2 second in the past and have no free will

[HamdenRice]

I was just wondering whether anyone else had come across this or pondered the neurophysiological work of Benjamin Libet, and the philosophical questions it raises.

Benjamin Libet did a series of experiments between the 1950s and 1990s that fundamentally challenge our subjective experience of reality and free will.

I won't go into the technical set up of his experiment, which is available on many internet sites. Basically at first, all he was trying to measure was the amount of time it took for a stimulus (say a pin prick on the skin) to be perceived consciously, subjectively by a person. Because of his collaboration with a neurosurgeon and consent of patients he was able to experiment on live human subjects before MRIs were available.

The results were surprising. After gathering data from the late 1950s until the 1970s, he came to the conclusion that it took about 500 msec for a stimulus to be subjectively and consciously perceived by a person. A half second was a surprisingly long time.

In effect, that meant that our conscious selves were "living" one half second later than objective reality. (In recent years, the amount of time has been challenged as much smaller, but in a sense it doesn't matter if the delay is much shorter, because as long as there is a delay, it means our subjective experience of reality and objective material reality were still offset.)

There were several equally disturbing corollaries.

The first dealt with the fact that people experience existence as happening "now". Libet proposed that because we live 1/2 second behind objective reality, our conscious brains then make up a story or illusion, called "subjective referral backwards in time" to make it seem as though our objective material experience of existence and our subjective internal experience of existence were happening at the same time. The experience is "antedated" from reality, in other words.

One essay I've read that discussed the amount of time it takes the conscious brain to parse grammar in conversation made me think of a metaphor for the world Libet described. If you speak a foreign language but are not fluent, when you listen to tv or radio in that foreign language it always feels that you are a half second or so behind, in putting together what the speaker is saying. Libet is saying that reality is like that, except that we then convince ourselves that the delay didn't happen.

Another troubling implication of the delay between objective reality and subjective conscious experience was that it should be impossible to do certain things if this were true. Humans do things much faster than would be allowed with a 500 msec delay. For example, it should be impossible to hit a fastball in baseball. It would be extremely dangerous to drive a car.

The solution to this quandry was solved by a set of even more disturbing experiments. Libet tried to look at the other side of consciousness -- volitional acts. He was able to use very precise markers and time recordings to determine when a person decides to lift a finger, when the various unconscious brain processes (eg motor, "readiness potential") involved in finger lifting began, and when his finger is lifted. (By this time, MRI was available.) The results of this experiment are what Libet is even better known for than the delay experiments or the theory of "subjective referral backwards in time" because they were more disturbing.

Libet found that the unconscious brain processes involved in lifting a finger occurred before the conscious decision to lift a finger occurred. The non-conscious brain prepares to do something before we consciously, subjectively decide to do it. Libet concluded that conscious free will was an illusion. Your unconscious mind is constantly carrying out your behavior, and then your conscious mind tells itself a story that says, "I did that."

This also solved the "subjective referral backwards in time" problem, because the conscious mind "dates" the stimulus at the time that the unconscious mind perceived it.

http://www.jstor.org/pss/187179

http://en.wikipedia.org/wiki/Benjamin_Libet

http://books.google.com/books?id=yHxJG56CnisC&pg=PA196&lpg=PA196&dq=subjective+referral+backwards+in+time&source=bl&ots=KGcp52q8PR&sig=REtd9pwBpe0c0OVLBp2tai-ABKg&hl=en&ei=6-5mSpf4MoGItgey1Ln2Dw&sa=X&oi=book_result&ct=result&resnum=5

edited for clarity and italics.

[bpcmxr]

1. Fascinating!

K&R.

[ashling]

2. Sounds like Libbet had too much time on his hands

about 1/2 second too much

:rofl:

[qazplm]

3. Whether it is our subconscious or conscious mind

it is still us. So not sure how it implicates free will. It might implicate the importance of subjective reality over objective reality to some minor extent. Almost nothing in the universe is instantaneous. There is going to be some sort of gap. Everything we see is in the past because it takes some amount of time for photons to hit our eyes. Same for sound, smell, and everything else.

The fact that we've (and one assumes to a certain extent all life) has come up with a trick to deal with the delay is impressive but does not in my mind (conscious or subconscious) implicate free will. At worst, it simply shifts it from totally being conscious decisions to being in whole or part subconscious.

[HamdenRice]

4. Libet also postulated that free will was the power to cancel unconscious action

In more complicated reasoning and interpretation of data he said that unconscious decisions could be canceled by the conscious mind, and that was where he posited conscious, subjective free will.

[qazplm]

7. well then

at the end of the day, your conscious makes the final call so you do have free will. So how does the fact that we live in the past by a near-infinitesimal amount of time mean we have no free will?

[HamdenRice]

8. Because under Libet's scenario...

the non-conscious part of your brain is deciding things before the conscious part of the brain -- the running monologue that you think of as "I" -- even knows what's happening.

Notice the OP says there is no "conscious" free will, not that there is no free will. The thing that has free will is the horse; the jockey's free will is the illusion.

[qazplm]

11. then first, you need to change your headline

because it says simply, no free will, not no conscious free will.

Second, the line between conscious and subconscious is so blurry and unknown that I see not how anyone can make such glib comparisons as jockey and horse or that one is "I" and the other is not "I."

For all we know, the subconscious is I too, and the conscious decision-making process is simply the final decision. In other words, the conscious mind has a lot of things it has to do, and if it's completely responsible for and focused on decision-making then that would I'd think make things difficult.

It's in my mind an artificial distinction to I am not sure what end. Our mind is a collection of parts, each working together, the conscious is but one of those parts, working with the other parts. It is not a horse and jockey, it is one combined entity.

[ixion]

5. very interesting...

thanks!

[phantom power]

6. Author Peter Watts likes to riff on that theme.

Our experience of consciousness is sort of like an executive summary prepared by the preconscious bureaucrats that do the real work and decision making.

It's the kind of idea that people love to hate, but it may be true.

[Gator_Matt]

9. Potentially flawed logic

Apart from some doubt I have about the accuracy of his timing (indeed the story admits large errors in measuring response times), I also have doubt in regards to hitting fastballs and driving cars. With those activities, you learn to anticipate the timing. In baseball, you start to swing well before the ball arrives; presumably your anticipate your own delay somehow and compensate.

I'm too lazy to look up the finger lifting experiment, but a crucial question would be whether the finger lifting is in response to some stimulus (e.g. pain). If that's the case, then there are already good explanations for unconscious responses.

Certainly the concept he proposed is interesting, but I have to be skeptical.

[Indenturedebtor]

10. Most subconscious and conscious actions are predetermined...

By how we choose to prepare ourselves for events before they happen.

Free will is not what happens in 500ms of a car crash... that's just reaction time.

Free will is what happens when you're deciding whether or not to marry a person, what career to pursue, whether or not to study hard for a test... etc.

Most decisions that you make in your life are made before you are actually faced with the situation to which they apply.

Libet was a good scientist though :) I had no idea he was so sensational in his time!

[RagAss]

17. I disagree.

What is your next thought going to be? The truth is you don't know, it will just appear and you will come in a nanosecond later and claim it was "you" who had it. Our brains operate like any other organ.
We do not "beat" our hearts. We do not have thoughts. "We" are what comes in later to claim the action.
The only lie is the ego.

[tinrobot]

18. You are not your thoughts.

Yes, thoughts may simply "appear," but there is still a more abstract part of you that observes the thoughts.

That part of you can also decide what types of thoughts to have. If I told you to think about something that made you very angry, you probably could do that very easily. Thinking angry thoughts would also cause you heart to beat faster, so in that sense, can control your heart beats.

[RagAss]

19. Yes, but is that abstract part of you the same you that you identify as "I"?

If you told me to think about something that would make me angry....then I would have to ask where did that thought come from that caused you to do that to me? Didn't that just appear?

[tinrobot]

21. Pretty much....

Descartes was little off when he said "I think, therefore, I am," because there's a part of you that witnesses the thinking.

If you learn to step back a little and watch your thoughts, you can see that most do just arise. If you want, you can also direct your thoughts towards certain subjects or areas. If you wanted to think about food, for example, you could easily do that. That part which directs your thoughts towards food, however, is the awareness that makes one conscious. That part of you is above thought and perhaps closer to the true "I".

Thoughts really are just an internal verbalization of ideas (i.e. a voice in our head.) But not all ideas are verbal or need to be verbalized. If you've ever gotten into a creative flow, you'll see that verbal thoughts start to diminish as you get lost in the process of creating.

[Jim__]

12. This equates consciousness with language.

In human beings, language is a big part of consciousness, but is it all of it? Can an animal that doesn't have language be conscious? Have you ever told a dog to stay, and another dog walks by? Most dogs clearly "want" to go to the other dog. They'll start the motion, but hesitiate, maybe whine a bit, then, depending on their training, either stay or go. Does the dog have language that constitutes its internal "I"? Is it possible that the dog is conscious without language?

Our conscious, internal "I" is a linguistic "I". It is the "I" of our internal conversation. But, do these thoughts originate as language? I think these thoughts have to originate in neuronal communcation, a language our internal "I" doesn't speak. So, all of our internal conversation arises as something other than language, neuronal communication that precedes our linguistic thought. It seems we are, at times, in control of this internal dialogue, even though the linguistic thought has to be preceded by processes outside the purview of our internal "I".

[HamdenRice]

13. Interesting take

I'm just not sure that the actual internal monologue was what he was measuring. In the volition studies, he was trying to measure when a person decided to lift a finger not necessarily when the person said to himself, "I'll lift my finger."

[Odin2005]

23. I tend to think in pictures and symbols, not words, something very common among us autistics.

the autistic animal behaviorist Temple Grandin being the most well known example because of her book Thinking in Pictures, she thinks completely in pictures. I actually have a hard time at "translating" my thoughts into grammatically coherent sentences, which is why I such at giving off-the-cuff explanations, instructions or directions.

[Odin2005]

26. KICK

[hunter]

14. We do stuff. And then we explain it later.

Anybody who's got themselves into an instantaneous life threatening situation involving physical trauma (car accident, explosion, gunshots) knows this half second gap, and may also know the half second gap is sometimes lost.

I've got a few half second gaps in my own memory. The deciding part never transfered the data over to the explaining part or the remembering part.

In the recording of accurate memories these gaps can be even larger.

If you are playing football and you get a concussion it's pretty easy to fill in the gaps with a reasonable explanation. But I've got a few WTF? gaps in my own memory that will never be filled in. (Some good advice: Never go rock climbing alone! Don't play with explosives!)

I loathe literature or movies where there is no gap between action and consciousness. People are utterly incapable of an instantaneous conscious response. The only "instant" responses are instinctive or achieved through intense and repetitive training.

The problem with this kind of training is that the trained response can be incredibly inappropriate in certain situations. The policeman who trains to shoot the bad guy pulling a gun on him might also shoot the kid with the toy or the guy reaching for his wallet. Kids go off to war and come back in ruins because the instantaneous survival skills they achieved at war are inappropriate in civilian life.

Humans are very sophisticated in the explaining part of consciousness, we can even explain things to others. But we've got pretty much the same instantaneous decision making equipment as any other highly intelligent animal.

[Odin2005]

24. Good post. Reminds me of Dan Dennett's description of consciousness as...

...a "Narrative Center of Gravity". There is no "Cartesian Projector" shunting things into conscious awareness, it's much more complex than that.

[bananas]

15. There's an interesting discussion at nature.com about fruit flies and free will

A couple of years ago, there was a bunch of news stories about an experiment indicating that fruit flies have some form of free will.
Here's an old news article at msnbc.com: Study hints that fruit flies have free will
One of the researchers, Björn Brembs, has more details at his website: Do Fruit Flies Have Free Will?

After reading your OP, I googled to see if there was anything new, and found this on Bob Doyles blog:

May 17, 2009
Martin Heisenberg on Free Will

This week’s Nature magazine (14 May 2009) has an essay on free will by Martin Heisenberg (son of Werner), chair of the University of Wurzburg’s genetics and neurobiology section of their BioCenter.

Since the indeterminacy principle was his father’s work, the comment that the physical universe is no longer determined and that nature is inherently unpredictable comes as no surprise.

What is unusual is that Heisenberg finds evidence of free behavior in animals, including some very simple ones such as Drosophila, on which he is a world expert.

He says:

"the activation of behavioural modules is based on the interplay between chance and lawfulness in the brain. Insufficiently equipped, insufficiently informed and short of time, animals have to find a module that is adaptive. Their brains, in a kind of random walk, continuously preactivate, discard and reconfigure their options, and evaluate their possible short-term and long-term consequences.

"The physiology of how this happens has been little investigated. But there is plenty of evidence that an animal’s behaviour cannot be reduced to responses. For example, my lab has demonstrated that fruit flies, in situations they have never encountered, can modify their expectations about the consequences of their actions. They can solve problems that no individual fly in the evolutionary history of the species has solved before. Our experiments show that they actively initiate behaviour."

When you combine some randomness with some "lawful" (read evolved and adequately determined) behaviors you get something like free will.

This is more or less exactly my work of the last few decades. Free will is a two-stage process.

<snip>

Heisenbergs article is behind a pay wall, but the discussion there is interesting,
and has this post by Björn Brembs (with several embedded links):

http://network.nature.com/groups/naturenewsandopinion/forum/topics/4760?page=1#reply-13970

Björn Brembs
25 June 2009 | 07:03

I have just read the two comments to this article. I’ve contacted Dr. Vermeersch about his comment. Here’s an excerpt of what I wrote:
-——
I have just read your commentary in Nature on the article of my PhD supervisor Martin Heisenberg on free will. Our group has recently found evidence for a plausible biological mechanism behind free will, which is close to what Martin Heisenberg was alluding to in his essay.
Reading your commentary, it occurred to me that it is possible you might not realize that in order for free will to make any sense, ‘free’ has to be separated from ‘will’. It is this separation that we believe we have found evidence for. Independent of us, the other commenter in the same issue of Nature, Bob Doyle, has developed similar lines of thought. He has also written a very nice summary of why the standard critique of free will fails . I think it addresses many of your thoughts expressed in the comment.
-——-
I have just recently learned of Bob’s interest in the matter and discussed some of these aspects with him over the phone last night. He has some more great information on the topic, such as a history of the debate and his own solution, the cogito model, which also comes very close to our interpretation of our data. However, for fruit flies, Bob would prefer prefer to call it the “‘biophysical basis for behavioral freedom’, which is conserved by evolution and shows up as a prerequisite for free will in humans.” Which is perfectly fine with me.

[RagAss]

16. You don't need Libet to know we don't have a free will.

If we had free will our lives would be perfect. No mistakes. No disappointments.

In reality, everything just happens and nobody does anything.

I knew this when I was 10.

[qazplm]

20. Huh?

Having free will in no way shape or form means no mistakes.

In order to not "make mistakes" or to be "perfect" or to not be "disappointed" you would have to have a complete knowledge of your own actions, everyone else's actions, most of which you cannot control, and then you would have to have complete knowledge of how every choice would play out ad infinitum.

A person with free will can decide they want my loved one's car, and shoot them in the head to do it.

All the free will in the world is not going to then make me not disappointed, and my life certainly isn't going to be perfect.

[tinrobot]

22. Everything is perfect.

We only think things are "mistakes" and get disappointed because we have egos that can't accept things for what they are.

[RagAss]

25. True.