Until recently, those interested in learning about consciousness have had just three options: (1) introspection (informative but deceiving), (2) books by philosophers (interesting but completely speculative), and (3) books by crazies (the majority of the literature on consciousness). Consciousness has long been a naughty word in science, but ho! No longer! While the “hard problem” of exactly why phenomenological states arise from the collective squirts of neurotransmitters washing across your brain at all is still a crapshoot, the relatively “easy problem” of correlating certain neural activity with certain phenomenological experiences is well underway.

Christof Koch of Caltech is one of the leaders in probing visual consciousness (or “awareness” if we are speaking to grant committees – shh!) – a particularly “easy” form of consciousness that is amenable to experiment both in humans. Dr. Koch’s “quest” is to identify the minimal set of neurons whose activation leads to consciousness. The book provides a grand tour of all the interesting quirks and subtleties of visual consciousness discovered in the last few decades, painting a picture that is far more fractured and fragile than our daily experience might suggest. If you still cling to the picture of the homunculus dictator riding a meatbag mech warrior around the world, this book will, at the very least, convince you that biological dictators can’t do their jobs without an army of unconscious robot agents. The book also includes some more speculative thoughts on the purposes and general nature of consciousness but, perhaps surprisingly for a book with such a lofty title, consists almost entirely of good old-fashioned science.

What Brian Greene’s The Fabric of the Cosmos is to modern physics, Quest for Consciousness is to modern neuroscience – the finest popular account available for lawyers, stock brokers, and mailmen with a bad science habit. Koch’s book might focus on visual consciousness, but he touches on learning and memory, motor control, and lots more on this quest and does so in his highly readable and concise style. While mucking around in neurobiology can make for dangerous trekking, Koch organized the book very well with small, informatively titled sections, making it easy to remember the salient point of a particular passage if you’re a neuro-rookie and easy to skim a particular passage if you’re a neuro-master.

For a more philosophical approach, I’d also recommend Daniel Dennett’s Consciousness Explained.

WARNING: The rest of this review is a collection of my reading notes. Readability not guaranteed.

• The evolutionary development of the brain makes it the ultimate kluge. New functions are continuous adaptations of old ones, making for some pretty wonky and unintuitive design principles. Speculative example: humans evolve disgust to avoid bad food. As humans form larger societies and viral epidemics become a problem, it becomes evolutionarily advantageous to avoid certain people. Rather than reinventing an avoidance mechanism, evolution simply co-opts the old disgust system (for dealing with bad food) to deal with potentially infected fellow humans.
• Is the function of emotions to allow detected correlations without known functional relationships to influence decision making? (In other words, I might not know by what mechanism two things are related but have unconsciously noticed a pattern in their coincidence.)
• Approach to decoding neural computation: consider that the typical sensory stimuli or brain info that feeds into a circuit will be highly tuned to the absolute scale, relative scales, and symmetries of that which it represents. Considering the nature of the input may constrain neural computation and suggest approaches to understanding it in a particular circuit.
• Does our consciousness integration window increase in unfamiliar environments and/or decrease in familiar ones? Does it increase or decrease in rapidly changing environments? How does one test the integration window in a dynamic setting? Traditional artificial masking protocols used in highly controlled environments don’t seem appropriate.
• As consciousness seems to change continuously, does this mean that the NCCs (neural correlates of consciousness) must be constrained in their activation patterns? How does the continuity of conscious experience arise from the somewhat digital spiking of neurons? Is there perhaps a continuous “read-out” process wedged between NCCs and qualia? Does the distinction between discontinuous and continuous dynamics suggest a useful approach to decoding neural computation?
• How does the brain optimize the balance between zombie agents and conscious processing? The zombie system offers speed at the cost of flexibility, operating through previously detected correlations and heuristics. Conscious processing offers flexibility at the cost of speed, offering a rich simulation of a series of events in order to consider and weigh consequences. (Simulation is the best word for this – you don’t know where your thoughts will end until you “run the program.”)
• How might one quantify consciousness? Do more explicit representations lead to more meaning and hence more consciousness? Would this justify deeming babies “less conscious”, since they have not yet developed the repertoire of explicit representations available to an adult?

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Dennett’s thought experiments and suggested activities for readers shed light on some fascinating phenomena of consciousness, including sensory dislocation & extension of self to tools and blind spots & the overly assuming nature of vision. This second investigation I found to be a powerful metaphor for much of the simulation that the brain performs in crafting our sensory experience. The discontinuity of consciousness is so striking particularly because of its apparent continuity. The brain doesn’t so much “fill in” the blanks as it ignores their presence. Dennett makes the important point that this absence of representation (ignorance) is not the same as the representation of absence (“filling in”).

The three themes of Dennett’s that resonated most with me were the relationship between time & consciousness, information sharing and information barriers in the brain, and consciousness as cultural software.

1) Noticing the varying speeds of sensory signal propagation outside of the body (light vs. sound vs. chemicals) and the varying speeds of neural signal propagation in the brain, Dennett points out that the “present” for us is really more of a “smear” in time rather than a “point”. He presents his Multiple Drafts Theory of Consciousness to show that in such a situation, different parts of the brain must act on different sets of information and, therefore, there is no single conscious experience. This is perhaps one of the most profound points that Dennett explores and he does so frequently throughout the book. Dennett also points out that temporal order outside the mind need not coincide exactly with temporal order as represented in the mind, though the two are correlated.

2) With so many specialized areas developing at different periods in human evolution, information sharing in the brain can be quite haphazard and arbitrary. The recognition that information may be present in one area of the brain but entirely unaccessible to another area is essential to understanding many functions and quirks of the brain. This is evident in many popular accounts of language disorders but Dennett also explores what this suggests for the evolution of consciousness. He imagines that early man armed with protospeech might have used “vocal autostimulation” (thinking out loud) as a means of bridging missing connections in his thought processes. In other words, if there’s no path from A to B in the brain, there might have been one from A to speech to hearing to B! This clever circuit could then have evolved into silent thought for more privacy and eventually developed into the “mind’s eye” visual experience of modern man. Even within the brain, there are likely many inefficient intermediary representations developed to bridge the internal “communication problem.” Beyond evolutionary explanations, this idea is also highly suggestive of neuroscientific approaches to creativity. Speaking out loud, doodling, and gesturing to oneself may be more than just nervous ticks or distracting habits; they may instead be integral yet inefficient attempts to circumvent the missing information pathways in the brain!

Dennett also includes a list of “primordial facts” that he claims any theory on the evolution of consciousness must explain. I found them insightful and important enough for any neuroscientist that I’ve included them here verbatim:

1. There are reasons to recognize.
2. Where there are reasons, there are points of view from which to recognize or evaluate them.
3. Any agent must distinguish “here inside” from “the external world.”
4. All recognition must ultimately be accomplished by myriad “blind, mechanical” routines.
5. Inside the defended boundary, there need not always be a Higher Executive or General Headquarters.
6. In nature, handsome is as handsome does; origins don’t matter.
7. In nature, elements often play multiple functions within the economy of a single organism.

3) As for the development of consciousness, Dennett proposes that viewing consciousness as cultural software provides an instructive and productive framework. His evidence includes the relatively recent development of consciousness (and therefore the reduced possibility that it is hard-coded). So why does consciousness still seem to be similar across cultures? Hardware biasing – we’re all still working with roughly the same base. Some interesting results of this hypothesis are that some humans may not experience consciousness, particularly babies and special cases of children who developed with very little social contact.

Just as evolution is a difficult topic to write on given that our language is peppered with words conveying “intent”, consciousness often has Dennett tripping over his own words. He fares far better than most, but be forewarned – books on consciousness can’t help but be clumsy.

In addition to being an excellent introduction for me to many theories on consciousness, this book has piqued my interest in the consciousness and cognitive development of children and the general AI framework known as SOAR.

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