salienceI was interested to see reports here and there the other day that scientists had discovered the seat of the will in the anterior midcingulate cortex.

That’s not precisely the case, of course; there’s an article here which describes the research. The scientists in question had an unusual opportunity to use electrodes in the brains of two patients; although they did indeed operate in the anterior midcingulate cortex they believe they were stimulating the brain’s salience network, which is quite widely distributed. The effect was apparently to create feelings of needing to persist against challenging circumstances; the researchers themselves call it “the will to persevere”. The patients were fully conscious and able to describe their feelings, but alas no tests were carried out to see whether they were in fact more persistent when stimulated.

The correct interpretation of the results seems difficult to me. As I understand it, the theory of the salience network holds that brain activity is controlled by neural networks which stretch across several regions of the brain. The default mode network, or DMN, is the one that operates when we’re not focused on anything in particular, perhaps daydreaming. It has been suggested that loss of this function is what distinguishes people who have “locked-in” syndrome from those who are in a “persistent vegetative state” – if you lose your DMN you’re not really there any more, in other words.

When we concentrate on a task, another network takes over – the central executive network, or CEN. The role of the salience network, if I’ve got this right, is primarily to act as arbitrator between the two. It spots something that deserves attention – something salient, indeed – and switches control from DMN to CEN. That’s fine, but it doesn’t seem to have much to do with persistence; it’s actually about changing the object of attention, not sticking with it. But perhaps strong or continuing stimulation of the salience network has that kind of effect. The salience network says “you need to look at this”, so perhaps when it operates emphatically we think “yes, I’m going to look the hell out of that alright; I’m going to look at that intensively; when I’ve finished looking at that, by golly it’s going to stay looked at”.

More plausibly it might all be to do with physiological effects; besides directing attention the salience network has a role in gearing up our “fight or flight” state, and it might just be that in that state we feel ready for a challenge ( in which case a readiness to persist comes into it, but surely isn’t the whole point); that would be a William James style emotion, originally a matter of the gut more than the mind.

Anyway, this really has nothing to do with an organ of the will. That is an interesting notion, though, isn’t it? My own assumption is that the will emerges from the operation of general cognition and that there couldn’t be a separate will module. If such a module determined the actions to be willed, it would surely have to encompass almost the whole of cognition, and so be far more than just a module; if it merely willed the actions selected for it by the rest of the brain it wouldn’t amount to much at all.

People do, of course, often hypothesise that there might be a special function for assigning value, or flagging up those things we ought to pursue as desirable. To me, though, that seems a bit different; the will, properly understood, is not a matter of basic motivation, but a faculty which might over-ride that motivation, either by operating at a meta level or simply by acting as a restraining and countervailing force.

Would that even be a distinct faculty of its own? Some would probably question whether talking about the will is a useful approach at all, rather than a relic from outmoded ideas about the soul controlling the body through acts of will. I must admit I find it hard to think of any subject that can’t be adequately discussed without mentioning  the will. Even free will doesn’t really lose anything if we talk about free action.  So is the will even worth persisting with? I can feel my DMN kicking in…

5 Comments

  1. 1. Vicente says:

    Pretty interesting. Recalling the “war on consciousness” post, I was thinking that it would be useful to have drugs that instead of acting on the reward (dopamine pathway) mechanisms, they would stimulate this salience network. Very useful for finishing boring tasks. Also, sort of noradrenaline attention effect. The anti-procrastinator.

    Regarding triggering the “fight or flight” response, I don’t know, this is an electrical and adrenaline mechanism launched when a threaten is subconsciously identified by the first stages of sensorial info processing. I find it difficult to believe that such a survival mechanism inherited from reptiles in evolution, is connected to higher cognitive apparatus involved here.

  2. 2. Arnold Trehub says:

    As I see it, the “will” network is a vacuous concept. For my take on needs, goals, motives, and effort, see “Set point and Motive: The Formation and Resolution of Goals” in *The Cognitive Brain*, MIT Press 1991.

  3. 3. Charlie Chapple says:

    I find it more helpful to think of the Salience System in terms of engagement and focus, than necessarily as ‘prep for fight or flight’. This should be an equally important perspective considering how it could relate to human learning.

    There seem to be certain phrases thrown around to get people’s attention. The findings are fascinating, but the article still leaves a lot for interpretation. It seems there could be a lot this system may be relevant too. Though it often seems as soon as neuroscientists try to pin down one brain system, they find five more.

  4. 4. Tom Clark says:

    Peter:

    “People do, of course, often hypothesise that there might be a special function for assigning value, or flagging up those things we ought to pursue as desirable. To me, though, that seems a bit different; the will, properly understood, is not a matter of basic motivation, but a faculty which might over-ride that motivation, either by operating at a meta level or simply by acting as a restraining and countervailing force.”

    Of course the will, in assigning a value or in over-riding motivation, has itself to be operating on behalf of some value or motive. So we can see the will as a separate motivational faculty is otiose (unnecessary) since the value it acts on is what’s really doing the willing/motivating. So I agree as you suggest that we needn’t invoke the will as a distinct faculty when considering our agential capacities. But we can perhaps think of one’s will as the motivational net sum of possibly competing desires that ends up driving behavior.

  5. 5. Vicente says:

    Tom:

    But we can perhaps think of one’s will as the motivational net sum of possibly competing desires that ends up driving behavior

    This statistic treatment of Denett’s pandemonium needs to be modulated and weighted, differentiating between: instincts, desires, wishes, intentions, cravings, etc etc, at conscious and subconscious levels. It is much more complex than that. To have a net sum, all the terms have to be in the same units, which I don’t think is the case. In particular, there is a kind of desire, one to strive for real happiness and get rid of the yoke of biology and ignorance, quite different from the others. I don’t think Dawkins genes really account for true altruism and kindness. Of course, statistically speaking you see this motivation in 1 out of 1.000.000.000.000.000.000.000.000………

    Being more objective, the point is to spot any altruistic behaviour for which you can’t find an egoistic ulterior motivation in any sense (for most there is one, I sadly agree). This, believe me, makes a difference for the possible explanations…. of course it is personal experience. For will to be, there must be options (choices), and when everything is clear, there are no options, just one way to flow along, no need for will.

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