Constructing Your Own Cartesian Theatre

Cartesian Theater
The Cartesian Theatre is the place inside your head where you sit and watch the world unfold before your very eyes. Well, not really. In order for cognitive scientists to better understand how our brains create an interactive conscious experience, they actually had to demolish the Cartesian Theatre in order to assemble a structure of brain and mind that better fit with the research.

The search for the seat of consciousness has been a long and tumultuous journey, and by no means have humans come near the hidden prize. But some ideas are better than others -- some have thought the thing through more clearly than others, incorporating more of the confirmed research data into more elegant theories.

In "Self Comes to Mind," Antonio Damasio reveals some of his deepest and most recent ideas regarding the origin of the conscious self. It is worth quoting from Chapter 9 of the book to illustrate Damasio's search for the origin of self:

Several possible structures come to mind, but only a few can be seriously considered. An important candidate is the thalamus, a perpetual presence in any discussion of the neural basis of consciousness, specifically its collection of associative nuclei. The intermediate position of the thalamic nuclei, between the cerebral cortex and the brain stem, is ideal for signal brokering and coordination.

Although the associative thalamus is busy enough constructing the background fabric of any image, it plays a very important, albeit perhaps not the lead, role when it comes to coordinating the contents that define the autobiographical self. I will say more about the thalamus and coordination in the next chapter.

What are the other likely candidates? A strong contender is a composite collection of regions in both cerebral hemispheres that is distinguished by its connectional architecture. Each region is a macroscopic node located at a major crossroads of convergent and divergent signaling. I described them as convergence-divergence regions or CDRegions in Chapter 6 and indicated that they are made of numerous convergence-divergence zones. CDRegions are strategically located within high-order association cortices but not within the image-making sensory cortices. They surface in sites such as the temporoparietal junction, the lateral and medial temporal cortices, the lateral parietal cortices, the lateral and medial frontal cortices, and the posteromedial cortices. These CDRegions hold records of previously acquired knowledge regarding the most diverse themes. The activation of any of these regions promotes the reconstruction, by means of divergence and retroactivation into image-making areas, of varied aspects of past knowledge, including those that pertain to one’s biography, as well as those that describe genetic, nonpersonal knowledge.

...One of the main CDRegions, the posteromedial cortices (PMCs), appears to have a higher functional hierarchy relative to the others and exhibits several anatomical and functional traits that distinguish it from the rest. A decade ago I suggested that the PMC region was linked to the self process, albeit not in the role I now envision. Evidence obtained in recent years suggests that the PMC region is indeed involved in consciousness, quite specifically in self-related processes, and has provided previously unavailable information regarding the neuroanatomy and physiology of the region. (The evidence is discussed in the last sections of this chapter.)

...The final candidate is a dark horse, a mysterious structure known as the claustrum, which is closely related to the CDRegions. The claustrum, which is
located between the insular cortex and the basal ganglia of each hemisphere, has
cortical connections that might potentially play a coordinating role. Francis Crick was convinced that the claustrum was a sort of director of sensory operations charged with binding disparate components of a multisensory percept. The evidence from experimental neuroanatomy does reveal connections to varied sensory regions, thus making the coordinating role quite plausible. Intriguingly, it has a robust projection to the important CDRegion that I mentioned earlier, the PMC. The discovery of this strong link occurred only after Crick’s death and was thus not included in the posthumously published article that he wrote with Christof Koch, in which he made his case.1

The problem with the claustrum’s candidacy as coordinator resides in its small scale when we consider the job that needs to be performed. On the other hand, given
that we should not expect any of the structures discussed earlier to perform the
coordinating job single-handedly, there is no reason why the claustrum should not make a relevant contribution to the construction of the autobiographical self. _Self Comes to Mind

Damasio also describes a number of other key brain structures -- including the brain stem -- in connection with their role in constructing a conscious self. The path to consciousness is serpentine, and feeds back upon itself in intricate ways.

Antonio Damasio

What is the point to this? Simply, if you want to understand the mind -- your own or someone else's -- there are a number of things which you will need to process almost simultaneously, at various levels of basic and emergent logic. You cannot do that without having done a great deal of reading, thinking, experiencing, observing, and experimenting. Fortunately for non-scientists, the entire human world is a great experimental laboratory for studying cognition.

Secondarily, if you want to create a machine consciousness, you may want to understand how the only proof of concept in the known universe -- the human brain -- manages to achieve the task at variable levels of competence.

Readings:

For an introduction to consciousness, Susan Blackmore's intro to the topic is one of the best places to start.

Antonio Damasio's book, Self Comes to Mind, is an interesting progression beyond an introductory review on consciousness.

At a somewhat deeper level, Gyorgy Buszaki's Rhythms of the Brain will connect many elements of neuronal structure and activity with higher levels of brain function.

A Dynamic Collection of Integrated Neural Processes, Centered on the Representation of the Living Body, That Finds Expression in a Dynamic Collection of Integrated Mental Processes

B&NReview
Cognitive scientist Antonio Damasio has authored some of the most successful, influential, and widely read popular science books on the mind. His latest book, "Self Comes to Mind," is an attempt at "starting over." Damasio wants to re-draw his vision of consciousness and the mind, on a larger canvas, and with the advantage of recent research findings and more comprehensive thinking on his own part.

But can a middle-aged man truly start over? Will society allow it? The publication of Damasio's new book has spawned a large number of published responses, from the respectful Jonah Lehrer interview, to the somewhat bemused Barnes & Noble review by philosopher A C Grayling, to the quasi-temper tantrum thrown by psychologist Alison Gopnik, in Slate.

When a person accumulates a body of work and thought, it is difficult to start over. And despite his claim, Damasio is not actually beginning again at the beginning -- that would be impossible. He is taking much of the respect and credibility that he has earned from past research and writings, and risking it all in an attempt to create something quite magnificent -- the beginnings of a seminal vision of how human minds work.

Damasio makes a case for the necessity of a "self", or subjective element, in the mind. And he locates the self precisely within the body -- or at least the parts of the brain that sense and map the body. Despite Damasio's claims of "starting over," feelings and emotions play central roles in this embodied self, this anchor of higher consciousness. In fact, threads of his previous thoughts pervade his newest work.

The author builds his argument chapter by chapter, bringing the reader up to date on known brain functions, theories of mind, and new research findings which utilise the latest tools. So far, so good. But then, in connecting the threads of self, the body, feelings, consciousness, perception, movement, attention, and some types of memory, Damasio climbs far out onto the brain stem. By doing so, he may be providing jealous rivals -- some of them possessing psychological chain saws -- an opportunity to cut him off at the stump. Damasio does not care. To Damasio, the vision is the important thing, not necessarily what others might construe of it. If the vision is true, eventually it will come through.

Damasio looks at the mind from the level of brain centers and pathways, and from the higher level of mental processes up to the self. Some readers will be satisfied with his weaving of the two levels together, and others will not. It is worth the time and the struggle, in my opinion, as an introduction to cognition.

The truly hard work has yet to be done. And since an ultimate understanding of the human mind -- as far as modern humans are capable -- will require a monumental acquisition of concepts as well as a monumental erasing of mis-concepts, it is unlikely that many of the current crop of cognitive scientists will ever live to see the promised land. Starting over is much harder than one might think.

Update 27Dec2010: Philosopher Ned Block takes a shot at Damasio's book in the pages of the New York Times. I admit to being a bit puzzled by Block's obvious and repeated mischaracterisations of some of the basic ideas in Damasio's book, until I reached the final paragraph in Block's critique. It seems that Block is disturbed that some of Damasio's ideas may be used to justify suffering by cows and chickens in the livestock and food production business. Apparently, Block did not read the book at all, but rather seized upon a few sections which raised red flags in the minefield of Block's politically correct consciousness.

You would be amazed how common it is that busy book reviewers fail to read the books they are reviewing. I suppose when one is politically correct enough, one hardly has to read or think deeply about an idea in order to recognise it as heresy. Understanding such emotional and reflexive "thinking" is part of the reason why thinking people should read books such as Damasio's "Self Comes to Mind."

Giulio Tononi's Theory of Consciousness

The New York Times recently did a piece on University of Wisconsin neuroscientist Giulio Tononi, which like most mainstream treatments of science failed to penetrate at all closely to the core. Instead, one would need to read this 2004 paper by Tononi to understand a bit of what Tononi wants to achieve.

Tononi has collaborated with Nobel Prize winning scientist Gerald Edelman on a number of books and studies. So you might think that Edelman's theory of consciousness would have influenced the younger Tononi's development of his own theory of consciousness.

There are bound to be similarities between Tononi and his mentor Edelman, but Tononi seems to be cutting his own path through the wilderness of consciousness. Unlike Edelman or Antonio Damasio -- another famous cognitive scientist -- Tononi does not appear to be as aware of his own body and the crucial role the body plays in generating consciousness.

Tononi's theory of consciousness penetrates more deeply into neurobiological realities than the philosophical work of David Chalmers and than the computational neurophilosophical work of Paul or Patricia Churchill. Yet it seems as if Tononi remains largely "stuck in his head" when attempting to tease the roots of consciousness.

Consciousness is extremely complex, but it is often made far more complicated than it needs to be. One of the favourite bugaboos of "philosophers of mind" is "qualia," or experiential quanta. Philosophers such as Chalmers enjoy riding mental merry-go-rounds such as qualia, because it provides them with arcane areas of expertise and plenty of material to publish -- regardless of any lack of practical significance in the real world. Academia is academia, and "publish or perish" says nothing about grounded relevance to the actual world. (For an interesting "party crashing" of some of the sensory phenomena related to qualia, see this [via commenter Loren])

And yet consciousness cannot mean anything unless it is indeed grounded to the real world. And consciousness cannot ground to the world by means of words. Even the best verbal metaphors of mentation cannot connect consciousness to physical existence. This failure of words is often the takeoff point for computational neurophilosophers and neuroscientists and theoreticians of sophisticated computational neural networks including Bayesian approaches.

But to be brutally honest, most scholars of consciousness do not even give lip service to the bare necessities of the physical underpinnings of conscious awareness and higher level consciousness. What about Tononi? I'm not sure yet. He showed a lot of promise in his earlier collaborations with Edelman. His "Integrated Information" theory of consciousness suggests some interesting possibilities, but so far I have not seen the necessary connecting, or grounding, of the mental processes with the bodily processes -- which are absolutely crucial.

Peepholes Into a Coherent World: BrainWorks Series

NewScientist

To most of us, the brain is a "black box." It creates a seemingly coherent world with which we can interact, but we have only limited understanding how it does what it does. But when focal brain damage happens to persons, neurologists and neuroscientists can begin to see how the brain puts the pieces of the puzzle together to create the world.

It's here that people with visual agnosias come in handy. Behrmann had previously studied people with integrative agnosia, who have difficulty recognising and naming complex objects as a whole, and instead seem to pay unusual attention to their individual features. One person, for example, mistook a picture of a harmonica for a computer keyboard, presumably thinking the row of air-holes in the mouthpiece were computer keys (Journal of Experimental Psychology: Human Perception and Performance, vol 29, p 19). Others have mistaken a picture of an octopus for a spider, and a pretzel for a snake.

In 2006, Behrmann put one of her patients, known as SM, through a series of experiments alongside people with normal vision. All were shown a set of three-dimensional objects on a screen, each made from two simple geometric shapes. Afterwards, the volunteers were shown a stream of these images, with a few new objects thrown in. Their task was to report whether or not they had seen the objects before.

While those with normal vision performed with nearly 100 per cent accuracy, SM made some intriguing mistakes. He knew he hadn't seen an object before if it contained a new part, but those that had the same parts in a different configuration confused him. About half the time he mistook these for the familiar objects (Journal of Experimental Psychology: Human Perception and Performance, vol 32, p 1169).

To Behrmann, the results suggest that our brains normally construct objects from a series of smaller building blocks, which she calls our "visual vocabulary". To recall our concept of an object, she says, we form a mental map of the way these parts fit together. It was at this stage that SM failed. "He had a good representation of the parts, but understood little of how they were combined," Behrmann says. _NewScientist

NewScientist

Advanced brain imaging is helping neuroscientists to sort between the different the different varieties of visual agnosias. This helps us understand the different functional brain modules, and to learn where they are located.

Brain scans have revealed that people with visual form agnosia tend to have damage to the ventral (lower) part of the brain's visual area. People with optic ataxia, on the other hand, have damage to the dorsal (upper) part. This led to the idea that we have two streams of visual processing. The ventral pathway is necessary for perceiving or recognising an object, while the dorsal pathway deals with an object's physical location in our visual field and, if we need to perform an action on it, guides the movement of our bodies. For this reason, scientists often refer to the two processes as the perception-action, or the what-where, streams of visual processing.

...In fact, the closer neuroscientists look, the more modular our visual systems appear. MRI scans of people with and without agnosias have suggested that within the ventral stream, separate aspects of appearance are processed independently. This year, psychologist Cristiana Cavina-Pratesi at Durham University in the UK found that shape, texture and colour are all processed in individual regions (Cerebral Cortex, DOI: 10.1093/cercor/bhp298).

Yet our experience feels markedly different. When we consciously see something, all these disparate elements are stitched seamlessly together, so we know instantly that an apple is smooth, green and round. The question of how we accomplish this is central to the study of conscious perception.

...So important is the role vision plays in most people's everyday lives that most research has concentrated on visual agnosias. Now the hunt is on for similar disorders that affect the other senses. Recently, for example, neurologists found a person who could understand speech but not other sounds. Coslett, meanwhile, is investigating whether simultanagnosics also have trouble binding other sensory sensations together, such as sights and sounds.

Now you see it...

There are many visual disorders, typically caused by damage to specific parts of the brain.

• Simultanagnosia - Seeing only one object at a time, even when viewing a scene comprising many items
  
• Integrative agnosia - Inability to recognise whole objects, tending to focus instead on individual features of an object
  
• Visual form agnosia - Inability to describe the shape, size or orientation of objects, yet exhibiting no problem in manipulating them
  
• Optic ataxia - Ability to report the shape and size of an object, though attempts to manipulate it are clumsy
  
• Prosopagnosia - Failure to recognise the faces of familiar people
  
• Pure alexia (aka agnosia for words) - Inability to identify individual characters or read text, even though subjects are sometimes able to write
  
• Agnosia for scenes - Inability to recognise known landmarks or scenes
  
• Colour agnosia - Ability to perceive colours without being able to identify, name or group them according to similarity

_NewScientist

We have discussed the binding problem before, but it is important to begin to zero in on the parts of the brain which are involved in binding different aspects of reality together into a "coherent whole."

It is also important to begin to learn the actual dynamic mechanisms which are responsible for creating the actual "sensation of consciousness." Or, "The Feeling of What Happens," as Antonio Damasio expresses it.

It is only by delving deeply into these processes that we will be able to conceptualise ways in which we may profitably reverse-engineer a human brain. But that will mean letting go of the "algorithmic theory of conscious intelligence" which has waylaid so many well-meaning artificial intelligence researchers in the past.

Scientific American has a short piece on a parallel topic

Beyond Kurzweil and Myers: A Useful Brain Emulation Viewpoint

George Dvorsky provides a measured and reasonable approach to the question of machines emulating the human brain in this well written article on "making brains". While quite short and lightly documented, Dvorsky's piece provides a useful outline of the problem, and a fairly sound description of a good approach for attacking the problem.

While I believe that reverse engineering the human brain is the right approach, I admit that it's not going to be easy. Nor is it going to be quick. This will be a multi-disciplinary endeavor that will require decades of data collection and the use of technologies that don't exist yet. And importantly, success won't come about all at once. This will be an incremental process in which individual developments will provide the foundation for overcoming the next conceptual hurdle.

But we have to start somewhere, and we have to start with a plan...The idea of reverse engineering the human brain makes sense to me. Unlike the rules-based approach, WBE works off a tried-and-true working model; we're not having to re-invent the wheel. Natural selection, through excruciatingly tedious trial-and-error, was able to create the human brain—and all without a preconceived design. There's no reason to believe that we can't figure out how this was done; if the brain could come about through autonomous processes, then it can most certainly come about through the diligent work of intelligent researchers.

...A number of critics point out that we'll never emulate a human brain on account of the chaos and complexity inherent in such a system. On this point I'll disagree. As Bostrom and Sandberg have pointed out, we will not need to understand the whole system in order to emulate it. What's required is a functional understanding of all necessary low-level information about the brain and knowledge of the local update rules that change brain states from moment to moment. What is meant by low-level at this point is an open question, but it likely won't involve a molecule-by-molecule understanding of cognition. _SentientDevelopments

Dvorsky goes on to describe the type of multi-disciplinary approach he has in mind, and bravely makes a prediction as to how long the effort will likely take: 50 to 75 years. This is a much longer timespan than Kurzweil and most AI researchers are giving, but I suspect it is closer to a realistic mark.

There are a couple of small criticisms I have to make. Dvorsky expects a workable brain emulation to be built within a "digital substrate":

.... if you believe that there's something inherently physical about intelligence that can't be translated into the digital realm, you've got your work cut out for you to explain what that is exactly—keeping in mind that any informational process is computational, including those brought about by chemical reactions. Moreover, intelligence, which is what we're after here, is something that's intrinsically non-physical to begin with.

Here, it seems that Dvorsky has it backwards. It is the persons who believe that intelligence can be made to work in a different physical substrate than the brain who bear the burden of proof to show that intelligence can be "transferred" to the "digital realm." We only have one proof of concept of intelligence up until now, which is a bloody ball of fat resting on a stalk rising between the shoulders of homo sapiens.

In another place Dvorsky asserts:

... the brain contains masterful arrays of redundancy; it's not as complicated as we currently think.

In truth, the brain is far more complicated than we can currently imagine. The question should be: Is the relevant functionality within the brain/mind which generates consciousness and intelligence, perhaps "not as complicated as we currently think?" Al Fin cognitive theorists believe that such a thing is possible, as long as we take care not to stumble amongst the numerous overlapping logical levels which present themselves whenever attempting to deal with this problem.

Dvorsky is quite right that the brain emulation problem is going to require extensive multi-disciplinary effort. We will need multi-disciplinary teams, as well as team members who themselves have multi-disciplinary training.

The great online debate between Ray Kurzweil and PZ Myers continues unabated, but it has very little to do with the eventual creation of a machine intelligence modeled after the brain.

If I had to choose one or the other to lead an effort to create an artificial brain, I would choose Kurzweil, hands down. Myers is an academic on the "intellectual" side -- an intellectual being someone who is rarely challenged by reality when he makes a mistake. Kurzweil's inventions and products have to work. That puts Kurzweil firmly in the reality-based camp, regardless of how many in the media and academia call him a kook.