Libet's experiments and the urge to act - what do you think?

[Graeme M]

Many may be familiar with the Libet experiments in the early 80s that suggested that the brain begins the process of preparing for a voluntary motor action before the subject decides to act.

Essentially Libet had subjects undertake a motor act - usually a flick of a wrist or finger - and note when they did this. He also recorded via ECG the brain activity to pinpoint any correspondence between subjective sense of the act and the objective neural activity underlying the act.

The times that were recorded were W, M, S and 0, where W is the time the subject perceived the urge to act, M is the time that the act was perceived to occur, S was the time that the subject perceived an electronic stimulus of the skin and 0 was the objective time of the act.

Subjects were to allow the act (wrist or finger flexion) to simply occur - that is, to be voluntary and not in response to any external stimulus - and not to prepare or pre-plan the act. It was found that the brain began preparation for the act via a Readiness Potential (RP) that arises some 500ms before the act. The W moment was typically noted at about 200ms before the act, and the M moment at around 85ms before the act.

Now, if I try this myself, I am simply not aware of any 'urge to act'. I can just sit here and then make my finger flex and hence clearly identify the moment it happens (M), but an 'urge to act' (W)? Not at all. Even if I try to keep my mind 'clear', I am simply not aware of anything other than the movement. How could I detect an urge to act, especially when you think it's within 200ms of the act occurring? That's a level of fine temporal distinction I don't think I can achieve.

Does anyone have any thoughts on what exactly Libet's subjects might be reporting?

[henry quirk]

If Libet's work hasn't been discounted, it has, at least, been called into question.

https://en.wikipedia.org/wiki/Neuroscience_of_free_will

Even Libet didn't/doesn't interpret his own work as a proof against 'free will'.

For myself: it seems to me I am an agent in the world, capable of choosing, capable of self-directing. Several folks, in-forum, argue such an assessment is simply misinterpretation on my part. Essentially these folks say I (and you) are nuthin' but bio-automatons.

Even if this is so, I'm not seein' how it practically matters. The illusion (if it 'is' an illusion) of intent and autonomy is strong and persistent, certainly plays a role in survival success, and probably shouldn't be monkeyed around with.

My point: one can fixate on the biology of the tree and totally miss out on the majesty of the forest.

[HexHammer]

I find Libet's experiment too narrow focused, too primitive, it doesn't account for long term and short term memory, nor subconciousness or fast reflexes where no thoughts are applied.

[Graeme M]

In posing this question, I'm not directly interested in Libet's experiment and what it illustrates, rather the idea that someone can be aware of an urge to act.

I certainly don't have that awareness and I'm beat if I can see what is meant by that. For example, I can simply choose to flex a finger. It just happens, there's no urge to act or prior sense that will happen. If I deliberate over it, and then say to myself, I will flex my finger, that deliberation can take as long as I want it to, so that clearly is not what is meant by the urge to act.

But even saying I am going to do it is not preceded by any sense of an urge. If I just sit here and then at random say "I'm gonna do it now", that sentence just springs forth, there's no prior sense of that, no sentence that says "I'm gonna say the sentence 'I'm gonna do it now', now".

Were the subjects just sitting there and suddenly had an urge to do it? If that is so, it's nothing I am aware of experiencing. In fact, that seems to make them appear to be automatons, quiescently awaiting the neuronal potential to cross the threshold of stimulating an action. So that cannot be what is claimed to be the W moment.

What then?

[Obvious Leo]

In process philosophy consciousness is modelled as a process and processes are events which occur over a finite interval of time. In the Libet scenario the decision to act must always precede the awareness of the decision to act because awareness is a subjective observation of a dynamic thought process. Naturally it is quite impossible to observe an event until after it has actually occurred so to translate this as simply as possible this means that it's impossible to be aware of having thought a particular thought until after we've actually thought it.