Some good things about Crick & Koch’s “Framework for consciousness.”

Science and Consciousness Review has just published a summary and four commentaries about the significant new article by Francis Crick and Christof Koch, titled “A framework for consciousness.” Most SCR commentaries in this series have been critical. I understand the criticisms. What may be lost in the debate, however, is an understanding of how far we have come in the scientific study of consciousness, in little more than a decade. In my view, Crick and Koch give us a progress report: Yes, there are many remaining gaps, but we are consistently learning more and more. Consciousness is back on the scientific frontier as a major topic, and there are signs of an early consensus on a number of questions.

Don’t forget how long human subjectivity was a taboo subject in science. In little more than a decade, we have come far in the scientific study of consciousness Even in 1995, John Kihlstrom tells us, he had a conversation with a famous cognitive psychologist who proudly boasted that in all his books he had always managed to avoid using the word “consciousness”! (Kihlstrom, 2003) That kind of “cryptobehaviorism” still prevails in some places. It is a carry-over of seven decades of behavioristic taboo against human subjective experience, perhaps the central topic of 26 centuries of philosophical thought.

Science has come back to consciousness only in the last decade or two. In that time, we have gathered a vast amount of evidence. Crick and Koch’s “Framework” tells a reasonable, early story about the role of consciousness in the mind-brain.

Let me suggest some ways Crick and Koch are moving the discussion forward.

1. The homunculus. Philosophers since Gilbert Ryle have told us there can be no scientific conception of “self,” in spite of both common sense and empirical evidence for it. Ryle ridiculed self as “the homunculus,” a little man inside of the brain that is supposed to look at incoming sensations. This was a dominant taboo for decades, and even today is taken seriously by some philosophers.

Yet we have known since the 19th century that damage to frontal cortex can cause a change in personality. Damage elsewhere in the brain can change the perceived nature of self, such as whether one’s left arm belongs to somebody else; and deficits of self follow predictably from such things as trauma and even hypnotic suggestion.

Well, if Crick and Koch are right, the “self” is back where it should be: As a major, testable question for brain and psychological science; it is associated with prefrontal cortex in humans, but of course it extends to many other parts of the brain.

To me that is progress.

2. Qualia. Philosophers have taught us to ask the question, “What is it like to be a bat? How can we be sure that your experience of ‘red’ is like mine?” They have argued for centuries that these questions cannot be solved.

I’m a skeptic about this line of attack on mental qualities; the evidence we have about the perception of red could fill a small library. All that evidence involves human beings telling us “yes, that object you are showing me, Mr. Scientist, looks red to me, and it’s different from pink and purple.” We are always getting phenomenological reports, and after 200 years we have found more and more evidence that a single, underlying neuronal system is responsible for that experience.

Nevertheless, philosophers are never satisfied, and Crick and Koch suggest that qualia may be the hardest problem. As they point out, science advances by solving workable problems. In Darwin’s time, “What is life?” was not a solvable problem. In the third millennium we know about DNA and a million other molecules that together provide a better answer. That is the strategy Crick and Koch advocate for qualia: Find out what we can today, and see if the barriers crumble as we learn more.

That may not sound like progress. But 100 years ago, when biologists were being attacked by vitalistic philosophers for not knowing what “life” really meant, their answer was to turn to solvable problems: fruit fly genetics, for example. Today we know the entire genome of fruitflies and human beings, and we are learning more every day. It is not a bad idea for scientists to do the same thing today with consciousness.

3. Zombie modes: Do you know how your eyes are moving right now? If you say this sentence out loud, do you know what your tongue is doing? The answer is: Uniformly no! Humans are unaware of automatic actions that are essential to our normal functioning. We have learned a great deal about such “Zombie modes” of processing in the last few decades. For example, we know that a new skill, like riding a bicycle, involves a great deal of activation in cortex as long as the details are conscious. When we become skilled and automatic, with fewer conscious details, we see a dramatic decrease in cortical activity. It is one of many pieces of evidence that suggests that cortex is involved in the contents of consciousness. (In contrast, the state of consciousness is maintained by brainstem areas).

4. Coalitions of neurons. We can be conscious of visual events, which we know involve visual cortex; or of touch, which involves a different piece of real estate, the somatosensory region. Yet both events are conscious — we experience them as conscious, we can describe them to other people, and different conscious experiences tend to compete against each other. (For example, try tying your shoe laces while watching a football game on TV; it’s hard to do, because those two conscious actions compete against each other).

A plausible idea is that each conscious content involves a specific “coalition” of neurons, which all work together to represent an event or a goal. Since there may be many coalitions at any time in a brain of 100 billion neurons, and since only one consistent event becomes conscious at any moment, it must be true that coalitions compete against each other, and the winner at any single moment becomes conscious. (Exactly what it means for a coalition to become consciousness at the neural level is of course one of the great unanswered questions).

What is important here is that the coalition idea moves away from Crick and Koch’s previous emphasis on single neurons, which by themselves are not adequate to account for the facts. This is part of the emerging consensus, expressed by Gerald Edelman and coworkers, and by Baars, Damasio, and others. Again, we are seeing signs of an early agreement on the essentials for a scientific theory of consciousness.

5. Snapshots. Neural coalitions last for only a short period of time, “snapshots” that can shift to from one to the next in fractions of a second. This point allows us to make sense of a very large body of evidence on the timing and integration of different sensory experiences.

6. Attention and binding. The role of attention is to push a coalition across the threshold of consciousness (although the exact nature of that threshold is not settled). There are two ways to do this: voluntarily (by asking people, for example, to shift attention from one thing to another), or involuntarily (driven by “salience” — by emotional and motivational areas of the brain, all the way down to the lower brainstem). Voluntary control in humans requires frontal cortex. Again, there is a wealth of evidence for this proposal.

7. Penumbra and Meaning. The “penumbra” or “fringe” of consciousness, in William James’ language, is all those conscious events that are not like coffee cups and musical melodies. They are “feelings of knowing,” esthetic judgments, senses of right and wrong — all experiences that are hard to characterize, but which people can often report with high confidence and accuracy. By listing this topic among the major questions of consciousness, Crick and Koch are joining the wide consensus that fringe judgments must be a significant part of the problem.

There are many other points worth noting in the “Framework for consciousness.” I don’t agree with all of it, just like the other commentators. But after almost a century of taboo, what Crick and Koch have given us is a first sketch of the nature of the topic, a plausible approach, and a description of the facts that most scientists will find reasonable.

Not a bad accomplishment.

© 2003 B.J. Baars

References

1. Kihlstrom, J.F. (2003) On B.F. Skinner – who, if his theory had been true, wouldn’t have been B.F. Skinner. Commentary on B.J. Baars, “The Double Life of B.F. Skinner.” Journal of Consciousness Studies. Vol. 10 (1).