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LATEST DIALOGUES What Scientific Idea is Ready for Retirement?

Image: Amanda Tonis

Image: Amanda Tonis

The Neural Correlates of Consciousness 

Consciousness is a hot topic in neuroscience and some of the brightest researchers are hunting for the neural correlates of consciousness (NCCs)—but they will never find them. The implicit theory of consciousness underlying this quest is misguided and needs to be retired.

The idea of the NCCs is simple enough and intuitively tempting. If we believe in the ‘hard problem of consciousness’—the mystery of how subjective experience arises from (or is created by or generated by) objective events in a brain—then it’s easy to imagine that there must be a special place in the brain where this happens. Or if there is no special place then some kind of ‘consciousness neuron’, or process or pattern or series of connections. We may not have the first clue how any of these objective things could produce subjective experience but if we could identify which of them was responsible (so the thinking goes), then we would be one step closer to solving the mystery.

This sounds eminently sensible as it means taking the well-worn scientific route of starting with correlations before moving on to causal explanations. The trouble is it depends on a dualist—and ultimately unworkable—theory of consciousness. The underlying intuition is that consciousness is an added extra—something additional to and different from the physical processes on which it depends. Searching for the NCCs relies on this difference. On one side of the correlation you measure neural processes using EEG, fMRI or other kinds of brain scan; on the other you measure subjective experiences or ‘consciousness itself’. But how?

A popular method is to use binocular rivalry or ambiguous figures which can be seen in either of two incompatible ways, such as a Necker cube that flips between two orientations. To find the NCCs you find out which version is being consciously perceived as the perception flips from one to the other and then correlate that with what is happening in the visual system. The problem is that the person has to tell you in words ‘Now I am conscious of this’, or ‘Now I’m now conscious of that’. They might instead press a lever or button, and other animals can do this too, but in every case you are measuring physical responses.

Is this capturing something called consciousness? Will it help us solve the mystery? No.


Copyright: Jolyon Troscianko.
We know how pain signals travel from a pinched arm into the brain and lead to activity in the anterior cingulate cortex. But what about the subjective experience of pain?

This method is really no different from any other correlational studies of brain function, such as correlating activity in the fusiform face area with seeing faces, or prefrontal cortex with certain kinds of decision-making. It correlates one type of physical measure with another. This is not useless research. It is very interesting to know, for example, where in the visual system neural activity changes when the reported visual experience flips. But discovering this does not tell us that this neural activity is the generator of something special called ‘consciousness’ or ‘subjective experience’ while everything else going on in the brain is ‘unconscious’.
I can understand the temptation to think it is. Dualist thinking comes so naturally to us. We feel as though our conscious experiences are of a different order from the physical world. But this is the same intuition that leads to the hard problem seeming hard. It is the same intuition that produces the philosopher’s zombie—a creature that is identical to me in every way except that it has no consciousness. It is the same intuition that leads people to write, apparently unproblematically, about brain processes being either conscious or unconscious.

Am I really denying this difference? Yes. Intuitively plausible as it is, this is a magic difference. Consciousness is not some weird and wonderful product of some brain processes but not others. Rather, it is an illusion constructed by a clever brain and body in a complex social world. We can speak, think, refer to ourselves as agents and so build up the false idea of a persisting self that has consciousness and free will.

We are tricked by an odd feature of consciousness. When I ask myself ‘what am I conscious of now?’ I can always find an answer. It’s the trees outside the window, the sound of the wind, the problem I am worried about and cannot solve—or whatever seems most vivid at the time. This is what I mean by being conscious now, by having qualia. But what was happening a moment before I asked? When I look back I can use memories to claim that I was conscious of this or that and not conscious of something else, relying on the clarity, logic, consistency and other such features to decide.
This leads all too easily to the idea that while someone is awake they must always be conscious of something or other. And that leads along the slippery path to the idea that if we knew what to look for we could peer inside someone’s brain and find out which processes were the conscious ones and which the unconscious ones. But this is all nonsense. All we will ever find is the neural correlates of thoughts, perceptions, memories and the verbal and attentional processes that lead us to think we are conscious.

When we finally have a better theory of consciousness to replace these popular delusions we will see that there is no hard problem, no magic difference and no NCCs.

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10 Responses to “What Scientific Idea is Ready for Retirement?”

  1. April 30, 2014 at 3:24 pm, donsalmon said:

    It’s often difficult to read Susan Blackmore’s writing while trying to avoid the conclusion that she has suffered from a stroke or has some form of autistic disorder. If she was a good writer, one might suspect she has spent years pretending to live in an Orwellian world where up is down and war is peace. Another possibility is simpler – psychosis (Huston Smith once spoke to a psychiatrist who had concluded that if someone truly believes in physicalism they could properly be diagnosed as having a psychotic disorder).

    Then of course there were the years of lying about her research – perhaps she’s just pulling our leg, and she’s not demented, psychotic or autistic, and she’s just pretending to believe that the sun is blue and the earth is pink.

    Then (substitute your own theory….

  2. August 13, 2014 at 3:17 pm, Stan Klein said:

    It was not amusing. It sadly was accurate of much too much neuroscientific thought. Perhaps I missed the intent of your remarks.

    Another difficult issue about NCC is that, assuming intentionality (in the Anscombe, not colloquial, sense of the word), consciousness (save pure consciousness — which, if it exists is attained by very few) always is about something. That being so, any attempt to radiologically locate conscious in the brain has the problem of knowing whether image activation represents “consciousness” per se, or the object of consciousness, both or neither. Perhaps there is no clear separation — but even that assumption requires serious conceptual analysis — and such is not apparent in psychology devoted to the topic (and I, being a neuroscientist in one of my several lines of professional identity, am quite well aware of what characterizes work in this field).

  3. February 19, 2015 at 6:36 pm, Jess Byrne said:

    Refreshing! I too believe neuroscientists will never find a physical, tangible, source in the brain for NCC. If anything, its in the heart because all of our organs and systems are conscious of themselves, even if we are not constantly conscious of them and the heart is the energy center for love: a divine and universal power. The lack of a scientific answer for consciousness is a gift. it leaves us in awe of thought, imagination, intuition, and the notion that there exists more of this in another timeless dimension. We innately long for the mystical, spiritual, higher self. Neuroscientists are amazing and they will infinitely discover new and wondrous workings of the brain, but consciousness is much more.

  4. February 21, 2015 at 8:10 pm, I Haddox said:

    great article. high time to zoom out and say that consciousness is both inside and outside the body, some sort of superposition/interplay with an as-yet-undetected ‘field’ that can’t be perceived using scientific instruments.
    even if you MRI someone playing jazz or rapping or meditating zen-like to a ‘mind of no mind’ state, all your little detector shows is the brain ‘turning off’ – and what good is that?
    new logics, say those induced by quantum computing, might lead to a better understanding or clever way of cracking this problem, a sort of ‘higher’ Binocular Rivalry..

  5. February 22, 2015 at 2:41 pm, ileana tellechea said:

    I talk about having an ineffable understanding of the consciousness of the mystical self only because I have spent many hours inside the deepest mystical states any human being could ever wish for. If not for that, I’d be lost by the same longings, which in fact I am, since I haven’t had one in many years. But the memories don’t let me forget. Falling into deep states during my sleep and remembering them after waking taught me that the sleeping mind is the key to understanding the consciousness that we long to explain. Experiencing the existence of a higher consciousness external to the human body is a realization every human should possess. Even if the recognition of the mystical consciousness happens in each individual’s brain, the fact remains that, one, the mystical consciousness is a distinct entity that cannot be reproduced at will, and two, there is a clear recognition between being in a mystical state and not being in one. I have no confusion about having been in many; it was not an illusion of my brain. A higher consciousness is not created by the brain, it is experienced by the brain in a co-existence.

  6. February 22, 2015 at 5:21 pm, Yubal Masalker said:

    I agree with the first part of this article which says that the NCCs are not really any capturing of consciousness. But I am skeptic about the second part which says that consciousness is just a delusion of mind. The arguments in the article in favor of the delusion of consciousness, is like saying that also life is delusion by using the arguments that life is nothing but just our breathings and our heartbeats, that life is nothing but only our mind’s delusion, that life is nothing but only series of thoughts and emotions and experiences and memories running sequentially in our mind. Another example for the apparent incorrectness of the argument in favor of the delusion of consciousness can be a mirror. Also when we try to find a mirror, one can say that there’s not really any mirror because mirror is just series of reflections of what’s standing in front of the mirror. That a mirror is just a delusion created in our mind due to the endless reflections we saw reflected from so many mirrors since our birth. But we know that a mirror is not really a delusion. We know that a mirror is a real existing object which just reflects by its in-built nature everything projected upon it. So it seems that also the pure consciousness is something like that. The pure consciousness is the most perfect in-built reflector possible. But unlike a common mirror, it does not reflect just the physical reality, but also the mental reality (thoughts, emotions, memories, experiences and their countless interplays).

  7. February 22, 2015 at 6:01 pm, Shaikh Raisuddin said:

    CONSCIOUSNESS IS REAL AND PHYSICAL. It’s automatic periodic process of change management.

    Yes NCC is misnamed. There may be NC of sleep/wake up but not NCC

    Everyone is conscious of CHANGE !

    Consciousness is an INTERFACE between external and internal world like touch screen of mobile.

  8. February 22, 2015 at 6:25 pm, Shaikh Raisuddin said:

    Yes search of NCC is absurd because whole brain is NCC

    But Consciousness is not illusory. It is real. It is an automatic periodic process of change management to sustain existence.

    Everything is conscious of CHANGE !

    Consciousness is an INTERFACE (change translator) between external and internal world like touch screen of mobile.

    Inertia (physical property of matter) is consciousness enabler.

  9. February 23, 2015 at 4:08 pm, Paul Bush said:

    This is the best a materialist science can ever do – deny that cosnciousness exists with the promise that the illusion will one day be explained by self-referential brain processes. Blind faith bordering on the religious.

    The OP seems unaware of the distinction between pure awareness on the one hand, awareness without an object, and consciousness on the other, which is always consciousness of something. It seems quite clear that the contents of consciousness are conditioned by the brain. Pure awareness, however, is not ‘generated’ by the neural process of representing a thought or object to some internal subject. It is what exists independent of this process, in fact any process. Ironically, rather than consciousness being an illusion of material brain processes, the material world is an illusion presented to consciousness.

  10. February 21, 2016 at 12:58 pm, Stan Klein said:

    The concluding thoughts of this “article” are mind (which is what exactly?) numbing.

    Consciousness is a delusion or perhaps, as per popular sentiment of pontificators of this viewpoint — an illusion. But delusion (or an illusion) is an experience. And an experience (as per David Hume and about 10,000 others possessed of a modicum of critical thinking) assumes (and requires)an experiencer.

    Hence, according to the benighted logic presented in this opinion piece, consciousness is an illusion had by an illusion.

    This is why psychology will have to start attracting folk with conceptual skills (i.e., educated and not just trained) or it will eventually sink of its own vacuity (or at least the well-established, oxymoronic,version — i.e., academic psychology).

    It is becoming abundantly clear that we credential folk way beyond their abilities.

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