I just finished reading Stanislas Dehaene’s Consciousness and the Brain. Dehaene is a French psychologist and cognitive neuroscientist who is bullish on the idea of consciousness being something that can be scientifically investigated. It’s an interesting book, one that I recommend for anyone interested in the science of consciousness.
Dehaene accomplishes his scientific investigation by focusing on what he calls “conscious access”, which is roughly equivalent to Ned Block’s access consciousness and David Chalmers’ easy problems, that is, the ability of our minds to hold content available for reasoning, decision making, and verbal report. He holds this distinct from the sense of self and metacognition, which he sees being built on top of it.
And as I mentioned in the last post, he is not concerned with phenomenal awareness, typically characterized as raw experience. He actually barely mentions it in the book, being largely dismissive of it. He characterizes the hard problem as ill defined, and the idea of qualia, pure mental experiences detached from any information processing role, as an idea that in time will go the way of vitalism. (Those of you who know me may wonder if I’m projecting my own views here, but no, my views in this area just happen to match his pretty closely, right down to using similar language.)
After discussing the empirical tests able to identify what kinds of stimulus lead to conscious perception, as opposed to unconscious ones, he identifies four signatures of conscious access:
- The amplification of an early sensory signal leading it to an “ignition” of circuits in the parietal and prefrontal circuits
- The appearance of a slow P3 wave in an electroencephalogram, a slow massive wave throughout the parietal and prefrontal regions about 300 milliseconds after the stimulus
- A late and sudden burst of high frequency oscillations, gamma band power
- A synchronization of information exchanges across distant brain regions with oscillations in sync
All of this is referred to as “the conscious avalanche”, the widespread activation of neural activity in a network including the prefrontal and parietal regions whenever a perception makes it into consciousness.
Which leads to Dehaene’s theory of consciousness, the global neuronal workspace, a variation of Barnard Baars’ global workspace theory. The main idea is summed up by Dehaene as:
When we say that we are aware of a certain piece of information, what we mean is just this: the information has entered into a specific storage area that makes it available to the rest of the brain. Among the millions of mental representations that constantly crisscross our brains in an unconscious manner, one is selected because of its relevance to our present goals. Consciousness makes it globally available to all our high-level decision systems. We possess a mental router, an evolved architecture for extracting relevant information and dispatching it.
…According to this theory, consciousness is just brain-wide information sharing. Whatever we become conscious of, we can hold it in our mind long after the corresponding stimulation has disappeared from the outside world. That’s because our brain has brought it into the workspace, which maintains it independently of the time and place at which we first perceived it. As a result, we may use it in whatever way we please. In particular, we can dispatch it to our language processors and name it; this is why the capacity to report is a key feature of a conscious state. But we can also store it in long-term memory or use it for our future plans, whatever they are. The flexible dissemination of information, I argue, is a characteristic property of the conscious state.
Dehaene, Stanislas. Consciousness and the Brain (p. 163-164). Penguin Publishing Group. Kindle Edition.
The workspace is held to be in a network of regions including the prefrontal cortex, the anterior cingulate cortex, and parietal regions. I’ve discussed before that the middle parietal regions are the central integration of sensory association processing in the cortex, and the prefrontal cortex is the central integration of motor planning, so it makes sense that these regions would be highly interconnected and interactive, with ongoing recurrent loops of communication between the sensorium and the motorium.
I’ve also written about the central importance of the prefrontal cortex in imagination, the simulation and evaluation of action scenarios. This fits with Dehaene’s view of the central importance of this region for the workplace. Indeed, Dehaene implies that conscious access is centered on the prefrontal cortex, which fits with its role as the executive center of the brain.
So this theory appears to have a lot going for it. And viewed from a purely instrumental perspective, it seems predictive of a lot of observations. Unlike Tononi’s Integration Information Theory, it doesn’t aspire to recognize consciousness in systems outside of the brain, just in the brain itself, particularly in human or primate brains. (Although Dehaene does think it could provide insights into possible architectures for consciousness in AI systems.)
And yet, like most grounded scientific theories of consciousness, I tend to think it captures aspects of the reality, but not the whole reality itself. Even if we restrict ourselves to conscious access, the descriptions of the workplace feel a bit too simple to me. It’s described like its one big thing, like a type of giant data bus.
This isn’t to say I think conscious access doesn’t involve wholesale activation of the regions that Dehaene discusses, but I’m not sure I buy the implicit description of it as one unified whole. Based on all the reading I’ve done, it strikes me more as a complex web of disparate subsystems communicating with each other, with cross talk between the streams creating an emergent thing that may resemble the global workspace, but more messy, noisy, and less coherent than the theory implies.
But maybe I’m just quibbling here. Dehaene might argue that it’s the final result that matters, and he’d be right. And the global neuronal workspace seems general enough to be compatible with a lot of observations, as well as other theories such as HOT (Higher Order Theory). I suspect before it’s over we’ll need a collection of theories to account for all observations. But only time and more research will tell.
SelfAwarePatterns 
Interesting post and good analysis!
“Based on all the reading I’ve done, it strikes me more as a complex web of disparate subsystems communicating with each other, with cross talk between the streams creating an emergent thing that may resemble the global workspace, but more messy, noisy, and less coherent than the theory implies.”
This isn’t an area I’ve given much thought to, or done much reading on, but I agree with your thinking there.
Two things struck me reading the post:
Firstly, I was impressed by the physical nature of “the conscious avalanche” for reasons you know me well enough to guess. 😉
Secondly, as I was reading, I found myself comparing the idea of workspace-based versus focus-based. From what you wrote, Dehaene appears to think mental content is brought into a WS in some fashion.
Other theories suggest the information is more spread out, which is what you seem to be saying, and we somehow direct our focus to it.
This is just intuition on my part, but it feels more like we direct our attention to areas of interest rather than, as it were, we view some stage where things parade before us.
Focus seems a simpler concept to me, for whatever that’s worth. Either way something controls focus, but a WS theory also requires a WS.
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Thanks Wyrd!
On workspace vs focus, that’s an interesting question. But I’m not entirely sure they’re mutually exclusive. Remember, the workspace itself is pretty vast, so being in the workspace involves being broadcast or echoing around. But focusing on something seems like it would involve various systems choosing to retrieve information from a particular region.
I guess the actual difference here is whether it’s a push or a pull. Initially of course, it’s always a push. But then maybe various regions decide if they want more, and if enough do, it becomes spread around.
In truth, it’s probably some messy mix. A region receives information, say on a percept, and it’s something that region cares about or not. If it does, maybe it signals for more information, or for specific details on the information. For example, if we’re looking for a path down a hill, the action planning regions in the prefrontal cortex may request details on visual percept of that path.
There’s a lot of writing about recurrent loops in the conscious parts of the brain as though the loops themselves are causal in some way, but I think they’re a consequence of the various regions talking to each other synchronously, which manifest as recurrent looping circuits spanning the network.
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“I guess the actual difference here is whether it’s a push or a pull.”
Good way to put it. Often seems like a pull, something grabs the attention, but who knows what the lower mind pushes to our attention.
“In truth, it’s probably some messy mix.”
Agreed.
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Dude. I’m tellin’ ya again. A group of neurons that supports semantic pointers a la Chris Eliasmith perfectly matches the functionality described by global neuronal workspace. Said semantic Pointers also perfectly matches the functionality described by the “qualia space” described by Integrated Informationj Theory. Said workspace located in the Thalamus (or even upper brain stem) would have the connectivity expected to explain the cortical activity described.
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[btw, if this tone is off-putting, let me know]
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Do you think there’s any resonance between semantic pointers and the second or higher order representations in HOT (Higher Order Theory)? They seem similar.
The problem with the idea of the workspace being in the thalamus, or any other one subcortical region, is that I don’t think they have the substrate. In Dehaene’s theory, the workspace is a vast network, a broadcast echo chamber, not something like a small scratchpad. And putting it all in the thalamus ignores too much observational evidence on what happens in the prefrontal, anterior cingulage, parietal, and precuneus regions.
It is true that a lot of the communication between the regions in the network go through the thalamus, but it’s acting more in the capacity of a network switch. (Although not completely, since nothing is ever cleanly delineated in biology.)
There is an interesting discussion in the book on pathologies that mess up the loop between the brainstem, thalamus, and striatum, which end inhibiting the excitation signals those regions send to turn on consciousness in the cortex, but that’s more like the light switch turning it on or off.
[Dude, be open to other theories 🙂 ]
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I guess I would have to read the book to understand why he thinks the workspace is vast when a small scratchpad would suffice. Actually, I think a small scratchpad that can only hold about 4 concepts at a time fits better with the data, as long as that small scratchpad has the potential to represent a vast array of concepts, just not all at once.
Nothing about the scratchpad being subcortical would preclude all of that cortical activity. (Those were cortical regions, right?) In fact, all of that activity is necessary to determine what actually gets on to the scratchpad. The thing is, I have trouble imagining how access consciousness would work in regards to a vast network, but I would have no problem at all understanding how it would work with a smallish number of neurons implementing a semantic pointer architecture.
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[I am open to other theories. But when I see these other theories line up with my own understanding, it’s hard not to go with it. All of these theories fit together, more or less. The same thing happens when I learn about all these other philosophers like Hume, Kant, etc. Just today I went to a meetup on Husserl’s Phenomenology, and I just mapped everything he said to my understanding and it all lined up pretty well. I’ve read a little bit of Heidegger, and that seems to line up too.]
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The descriptions of the workspace are, in my opinion, unfortunately vague, so it’s easy to project a lot of different concepts unto those descriptions. But if you understand that Dehaene’s motivation for the theory comes from the empirical data showing widespread activation of the regions he includes in it (yes, they’re all cortical), it starts to make a bit more sense.
None of that is to say it isn’t possible that something is kept in the thalamus. A lot of communication does go through it. It wouldn’t surprise me if evolution didn’t make use of that fact. But it would indeed have to be fairly lightweight.
I think I’ve noted before that I see the thalamus and cortex as one integrated system (the thalamo-cortical system). (Incidentally, that integration, between the diancephalon and the telencephalon, is ancient, going back to early vertebrate evolution.) So, when I talk about the prefrontal cortex, I’m also talking about the medial dorsal nucleus in the thalamus, and when I talk about the parietal region, I’m also talking about the thalamic nuclei that project to it. It’s just tedious to mention that every time.
[On mapping concepts to existing understanding, I do the same thing, although we have to be careful not to be too aggressive with this. Sometimes we’re encountering a truly new concept. But it’s good to figure out where it intersects with what we already know.]
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A workspace does seem to match the way we “feel” about consciousness, as if there is an “I” sitting here, somewhere in the brain. I’m actually reading (at last) Michael Graziano’s Consciousness and the Social Brain, so I’m a little behind the curve, but getting there. Lots of interesting stuff in that.
As I woke this morning, I became aware that I was moving into consciousness from sleep, and that the dream I had been experiencing was slipping away from me. At that moment, I realised that I had been aware of the dream whilst asleep, but not conscious of it – a distinction that had not really occurred to me before.I became conscious of the dream, not surprisingly, as I entered the state of consciousness.
As I read more about the subject and think more about it, still none of it feels like a “hard” problem. I’m convinced that some people are wired to think of it as a hard problem, just as some people are unable to imagine a universe without a god or other spiritual entities directing us.
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It’s been a while since I’ve read Graziano. (Occasionally I think about re-reading him in light of everything I’ve learned since then.) The biggest thing I got out of his book was his approach. The idea that awareness is data, what he calls the attention schema, and that we should be leery of magical steps in any explanation of consciousness, was pretty eye opening. That magic step issue is why I’m not a fan of IIT, or most theories born out of straight physics.
Dreams are an interesting conundrum. Many people consider us to be conscious while we’re experiencing them. But are we? Or are we just interpreting information left afterward as a memory of the experience? Brain scans of people who are dreaming seems to imply that there is some experiential component there, but it remains a question for me how conscious we really are while having them.
I’m with you on the hard problem. I think it’s actually the psychological difficulty of reconciling a model we hold of ourselves with what we know about the brain. But in the absence of specific details to account for, that’s just an intuition difficulty, and science has shown us time and time again over the centuries not to trust our intuitions. Once we accept that we should bracket our intuitions in this area, the hard problem seems to disappear.
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“Many people consider us to be conscious while we’re experiencing them. But are we?”
I think so.
I have a lot of experience watching sleeping dogs (because you’re supposed to let them lie), and watching their various muscles twitch in what seems running and chasing and even barking.
Sleeping people likewise seem to go through an experience of some kind. I once kicked my ex-wife while I was sleeping. (Didn’t hurt her, but woke her up, and she woke me up wanting to know why I’d kicked her.) At the time I was having a dream involving playing football and had just kicked one. Being woken up, that was fresh in my mind.
And I’ve certainly observed apparent real-time behavior in sleeping people.
How meaningful any of that is… [shrug]
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You might be right.
My alternative interpretation (speculation) begins with pondering why we dream. I wonder if it isn’t the hippocampus consolidating memories. Which might make it a disjointed hodge podge of semi-episodic images, which might well cause the outward muscle twitching you observed. With us building an interpretation of a story when we wake up.
But that doesn’t necessarily mean we aren’t conscious in some manner while that’s happening. There are three types (at least) of consciousness:
1. awakeness / vigiliance
2. subjective experience
3. self reflection
Someone in a vegetative state can have 1 without 2 or 3. When we’re dreaming, it seems like 1 is off, but 2 is active, and maybe 3 in some reduced capacity.
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I’ve twice managed lucid dreams, where I was aware I was dreaming and able to think about that and do things, act on those thoughts.
In the second one I was able to hurl crates against a wall with my mind! I just mentally crushed a few, too. Both times I was indoors and couldn’t try flying.
When I awoke I remembered the dream experience, but I’m pretty sure (but who knows, right?) I also remember being in the dream. It’s not just a memory of experience, but something more layered. It does suggest #3 on your list, though.
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I have once or twice figured out I was in a dream and then worked to wake myself up. Once I woke up, but was still dreaming, before finally waking up from the whole thing. At least, that’s the way I remember it. So definitely 3 can spike in a dream.
But it does seem that for most dreams, 3 is fairly inhibited.
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Yeah, kind of a passive observer to a really weird movie you’re the star of. 😮
FWIW, here’s another data point. I’ve never had a nightmare. (The one time, as a small child, my parents accused me of having a nightmare, it turned out I really had seen a rat run across the floor. But not knowing about rats then, I could only tell my parents I’d seen a “bird” run across the floor and it had scared me. Obvious nightmare, right?)
But as an adult, anytime a dream gets too uncomfortable, some part of me says, “Hey, wait a minute,… this is my dream,” and the situation changes.
Like one time I was a passenger in a car driven by a friend, and then (as dreams do) suddenly I was running from the car and there was gunfire. I thought, Hey, wait a minute,… turned around, and was suddenly in some completely other dream.
So I’ve never really experienced nightmares or recurring dreams or any of the popular ones about being naked in class or whatever.
I sure do wish I could manage flying in a lucid dream, though. That’d be so cool.
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I envy your ability to avoid nightmares. I’ve had my share. (And the fact that I talk like this, and given my view that consciousness is in the eye of the beholder, is making me lean toward them being conscious experiences in every way that counts.)
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I’ve come to realize it’s a blessing. I love my dreams! I sometimes wake up laughing and thinking, “I’d pay money to see that!”
That I can wake up that way, or that you can wake up having a physical reaction to a dream, really does suggest we experience them phenomenally.
For me it’s pretty clear in sleeping dogs. The movements aren’t random. You can almost tell what they’re doing. There’s coordination there that strongly suggests real-time experience.
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The discussion of dreaming reminds me of the difference between phenomenal and access consciousness. What if there are two workspaces, one for phenomena and one for access? The senses (and other cortical areas) populate one (or more) phenomenal workspace, but only a few concepts get promoted to the access workspace. The phenomenal space would constitute a short term memory. If a concept there doesn’t get promoted to the access space it will dissipate.
The dreaming state then would populate the phenomenal space, but the access space is shut down. That is, until you wake up, at which point the phenomena left over from the dream still populate the phenomenal state and can therefore be promoted to the access space.
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I don’t know that a clean separation can be made in that way between phenomenal and access consciousness. But on the idea of two workspaces, I can envisage a sensorium workspace and a motorium one.
The sensorium workspace would be in the back parts of the brain, and would be centered in the superior parietal lobe (the precuneus) (and associated thalamic nuclei). It would house exteroceptive and interoceptive perceptual information. Note: this isn’t equivalent to phenomenal experience because it’s mostly missing associated affects, the feeling part of the experience.
The motorium workspace would be in the prefrontal cortex (and associated thalamic nuclei). It would house references to the content of the sensorium workspace, using higher order action-oriented representations (including perhaps semantic pointers). This workspace would include affective feelings generated by the lower motorium (midbrain and limbic system).
The motorium workspace would constantly be retrieving information from the sensorium workspace, as well as from many of its surrounding regions, as well as pushing top-down attention. This would generate the recurrent feedback loops that many scientists see as a chief signature of consciousness, although as I’ve noted elsewhere in this thread, the don’t see the loops so much “generating” consciousness but as a consequence of the information processing involved in it.
All that said, I’m not sure what this would mean for dreaming. Supposedly the prefrontal cortex is less engaged (although not entirely shut down) during dreaming.
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Okay, you want to say sensorium instead of phenomenal, and motorium instead of access. That’s fine. So I have two questions.
First, do you think mammals without a developed prefrontal lobe have a motorium of sorts involved in managing their actions?
Second question: how do you imagine “retrieving information” might work with neurons?
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“First, do you think mammals without a developed prefrontal lobe have a motorium of sorts involved in managing their actions?”
Definitely. Motoriums predate nervous systems. https://selfawarepatterns.com/2019/03/04/the-sensorium-the-motorium-and-the-planner/
“Second question: how do you imagine “retrieving information” might work with neurons?”
That’s a complex question. But I think the initial pattern of spikes from the sensorium causes a neural firing pattern in the motorium, which interacts with other patterns there, and may result in spikes back to the sensorium, where the patterns there cause spikes back to the motorium. (The motorium is requesting more information after being informed of a new percept.)
The result of this recurrent feedback loop, this interactive conversation, is the patterns in the motorium become increasingly refined based on the patterns in the sensorium. But it’s important to understand that the pattern in the motorium isn’t a copy of the one in the sensorium. It’s a unique pattern for its own needs, the need of planning actions. In HOT terminology, it’s a second (or higher) order representation of the lower order one in the sensorium.
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The following assumes you locate the motorium in the prefrontal cortex (possible including related areas of the thalamus)
Next questions: Does the motorium in an organism without a nervous system work in a way similar to a human, that is, similar enough to use the same word for it?
If my above assumption is correct, do you see evolution moving the motorium around, ending up in the prefrontal?
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The motorium is actually a multilevel thing. It exists at a basic reflexive level in the midbrain, at a habitual level in the basal ganglia, and a higher level in the frontal lobes. I’ve often referred to the prefrontal part as the planner, what many neuroscientists refer to as the executive. The prefrontal cortex is large in primates, and very large in humans in particular.
The motorium is the sum total of an organism’s abilities to produce action and behavior, to affect both itself and its environment. That obviously is a very broad concept, which can include unicellular organisms, but also plants. Obviously the motoriums in these organisms is much simpler than those with brains.
But I think what sets animals apart that we’re tempted to label “conscious” is complex communication between the motorium and sensorium, an ongoing conversation that results in a constant feedback loop, the recurrent processing a lot of people focus on. The communications between a unicellular sensorium and motorium tends to be one way, feed forward only.
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“But I think what sets animals apart that we’re tempted to label “conscious” is complex communication between the motorium and sensorium,”
As an aside, without disagreeing with anything, what’s wrong with giving it a label? It’s a real process with real results (us having this conversation, for instance). “Consciousness” is as good a name as any.
Is your objection more to the metaphysical weight people tend to give the idea? Perhaps that’s what you see as the real error?
I think the problem is that, given the {{Okay, if I can’t call it “special” what concept would you agree is characteristic of human consciousness? advanced? highly-evolved? I’m guessing “unique” won’t fly. If I say “nature” and by that mean the high degree of information processing (quasi-IIT), how about that?}} nature of {whateverwecallit}, and given the direct personal nature of phenomenal experience, that metaphysical weight seems inevitable.
People gonna people!
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“As an aside, without disagreeing with anything, what’s wrong with giving it a label?”
You can give it that label if you want to. And I think it might be a productive one. But a lot of people won’t sign on to it.
I just commented to someone else (not sure if it was on this thread or another) that I’m starting to see why so many people troubled by phenomenal consciousness are attracted to panpsychism. It reconciles the feeling that something special is happening with the apparently normal physics going on in the brain.
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FTR: I’m not attracted to panpsychism. My thermostat isn’t conscious. 😉
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Sorry, I didn’t mean to imply you were. Just thinking out loud.
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Sorry, I didn’t mean to imply you were, either. I saw your comment in the other thread and meant to just mention, in passing, that I wasn’t. You re-made the comment here, which let me do it here. My comment, likewise, an aside.
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Funny I am an atheist but also think there is something like a hard problem.
“According to this theory, consciousness is just brain-wide information sharing. ”
I can not put my finger on it, but I don’t like these sentences. Consciousness is what it feels like to have brain wide information sharing. To say consciousness is brain-wide information sharing, is like the behaviorist are trying to take over again. Dennet (a behaviorist) refers to Dehaene ( a behaviorist) and his research. The research is great also. But to play these word games and make the problem go away. There is no reason that brain wide information sharing should have a feeling to it. I am not a master of the history of these subjects and behaviorism, but I would say you just have pigeon people and non pigeon people. For the non pigeon people a short new book (Consciousness) just came out. Annaka Harris the wife of Sam Harris, the meditation guy and the making sense podcast, wrote a introduction to the problem. I think it pose and explains the problem of consciousness well.
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“I can not put my finger on it, but I don’t like these sentences.”
From most people’s perspective, it’s a very deflationary account of consciousness, so deflationary that many people equate it with illusionism. Dehaene doesn’t discuss illusionism, but he’d definitely not concerned with phenomenal properties.
Behaviorism is a vague term. Many people seem to fling it at anyone who doesn’t consider introspection completely reliable. But there are positions between regarding introspection as reliable and completely ignoring self report. A case can be made that we should consider self report as data to be accounted for (Dehaene does), but when that’s the only source of a conception, we should be cautious in assuming that conception is real.
I’ve heard of Annaka Harris’ book, but haven’t had a chance to check it out yet.
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The more I think about it, And my thinking, reading and general knowledge is definitely in a lower gear then yours, I think we are often disagreeing because we look at the issue from a different perspective. Annika Harris really handles the question what and why there is phenomenal consciousness, to which there is no good answer and a lot of the second part of the book explains pan psychism which seems the only reasonable answer.
Then you and other people think more about what consciousness does and what it function could be in the brain. Which is almost 100 percent related but slightly different. greetings
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I’m increasingly starting to see why so many people concerned about phenomenal consciousness are attracted to panpsychism. I noted in a post a while back that panpsychism is actually observationally equivalent to apsychism, the belief that phenomenal consciousness doesn’t exist. In both cases, we shouldn’t expect to find anything different in the physics of brains compared to outside of them.
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Eyeballing Harris’ book, it looks brief and basic (and pricey for the size). Would you say it has new insights that make it worth $13?
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I would say for you it is a little bit expensive. The audio edition was only 2 hours something and I thought it was an error.
But I do like the Harris people and I don’t want to be on the record saying her book is not worth to be bought.
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It seems he is talking about a fairly narrow range of brain functions, something more like the “aha” moment or the “recognition” moment. I guess it is okay to define “consciousness” that narrowly but what about everything else? Particularly everything leading up to that moment.
“According to this theory, consciousness is just brain-wide information sharing. ”
Is he saying things in the unconscious cannot be/are not shared?
How would you explain psychosomatic illness or placebos? Apparently in these cases something is shared sufficiently to cause physical symptoms. Or, subliminal perception?
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This is interesting.
https://journals.sagepub.com/doi/abs/10.1177/1073858411404079?journalCode=nroa
“These findings challenge the pivotal role of the prefrontal cortex in consciousness. Instead, it appears that specific brain areas (or cognitive modules) may support specific cognitive functions but that consciousness is independent of this. Conscious sensations arise only when the brain areas involved engage in recurrent interactions enabling the long-lasting exchange of information between brain regions.”
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The role of the prefrontal cortex in consciousness is controversial. My take on it is that it’s crucial for the higher order aspects of consciousness, such as introspection and imagination. But it’s important to understand that these are coordinating roles, not where it all happens. It depends heavily on functionality from the parietal, temporal, and even occipital regions.
The interaction between all these regions ends up being continuous loops of signalling, the “recurrent interactions” the authors mention. But I think focusing on the recurrent interactions, in and of themselves, as though they magically generate awareness, is wrong. Those interactions are a consequence of the two-way communication, the coordination between the prefrontal cortex, anterior cingulate, parietal, and other regions, not the cause.
It’s also worth mentioning that the prefrontal cortex is a large region (particularly in humans). Stimulating some parts of it in isolation, even repeatedly in a recurrent fashion, probably won’t generate conscious awareness. The dorsal and anterior regions in particular seem more involved in metacognitive and global awareness.
But even if the prefrontal cortex is knocked out entirely, a person might still be able to perceive their world and engage in habitual or reflexive action. We might still regard them as conscious, but it would be in a reduced capacity. Such a person is pretty disabled, much of their personality lost.
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“Particularly everything leading up to that moment.”
He actually spends a good amount of time discussing preconscious perception, and what it takes for it to make it consciously accessible. If I recall correctly, we need to see an image for at least 50 milliseconds for it to have the potential of making it into conscious awareness. But even if the image lasts longer than that, it can be defeated if we’re quickly shown a new image.
“Is he saying things in the unconscious cannot be/are not shared?”
The sharing of unconscious content is limited. It can be shared between a few regions, but generally doesn’t make it to most of them. He divides the unconscious into different categories.
1. The subliminal, perceptions that will never make it into consciousness
2. The preconscious, perceptions that may make it into conscious access if we attend to them, but will quickly fade if we don’t.
3. Unconnected processes, like the autonomous processes regulating heartbeat, metabolism, etc.
4. Memories we’re not current accessing.
(There may be others I’m not remembering.)
“How would you explain psychosomatic illness or placebos?”
I think in these cases we’re talking about local unconscious content influencing what is perceptions that do make it into conscious access, but that the influencing content itself doesn’t make it. But that’s my understanding. I’m not sure how Dehaene would respond.
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>>>the idea of qualia, pure mental experiences detached from any information processing role<<<
I don't know whether qualia play an information processing role, but clearly my experience of red exists. Therefore, qualia exist. Unless he's denying that the experience of red exists. Does he deny that?
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I don’t think he does. Only that it’s something separate and apart from the operations of the brain. Unfortunately, philosophers have made a mess of the word “qualia”.
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