Larry:

A very thought-provoking card! This is an area that has always interested me and I have about a hundred things to say. So much, in fact, that I am generating TWO cards on the subject. In this card I present my vague theory about how the brain might work and in the next I try to answer your questions about IQ testing.

First, on the subject of central processors... There is no doubt in my mind that the human brain is a computer, but as I've mentioned before, the computer is a much broader concept than most people realize. It seems equally clear that the architecture of the brain is radically different than that of any computer now in existance.

A standard computer such as our beloved Mac has a very rigid, centralized, synchronous structure. Everything passes through a "Central Processor" (or CPU) and all events march in lockstep to the ticking of a single clock. The brain seems to be much more asynchronous in the firing of its signals, and its processing seems to be much less centralized.

I have a theory about brain structure that goes something like this: back in the deeps of time when we were all squigling around in some swamp, our nervous systems consisted of a set of essentially separate processing networks performing (relatively) low level tasks. In a frog, the motion detectors which spot flies are wired DIRECTLY to the tongue. When the doctor taps our kneecaps it only takes a few neurons in our spinal cord to react (our brains find out what happened after the fact). There are a thousand similar "Processing Loops" in nervous systems everywhere which begin as a detector wired to an effector.

Natural selection constantly prods all of these loops to become more clever. A frog who can tell the difference between a fly and a moving finger will eat more regularly than his less clever contemporaries and thus has a better chance of living long enough to reproduce and pass on his clever fly catching loop. Thus a few extra neurons are inserted into the loop between eye and tongue and the same thing happens to all the other loops in the system.

Another thing that happens over time is that the different loops start exchanging information. When the right hand begins to see what the left hand is doing the payoffs are enormous! Different loops eventually merge into "larger" loops with all sorts of detectors on the input side and all sorts of effectors on the output side. The result of all this merging is a brain or "CENTRAL Nervous System."

So although the brain as a whole can be seen as a Central Processing Unit, it is also a hodgepodge of independent and sometimes conflicting decision loops. We each possess what Marvin Minsky calls "The SOCIETY of Mind." There is an eternal cocktail party going on inside our heads with many voices competing for attention. And yet we think of ourselves as "individuals" as if there was a single captain at the rudder.

The reason for this, I think, is that the experience of consciousness arises primarily from one very special processing loop: the language loop. It is this one loudest voice at the cocktail party that is the focus of our attention. (In fact, it's the ONLY actual "voice" at the party.) And this language loop is mostly what gets measured when we try to measure IQ.

This leads me to my LOOPY THEORY OF CONSCIOUSNESS. As I see it, there are two major loops involved in consciousness, the language or ear-mouth loop, and the spatial or eye-body loop. They both followed the same evolution and eventually became severely intertwined.

In both cases the loops formed almost by "accident." The ear probably began as a simple "BANG!" detector and evolved into an auditory processing system that could distinguish between and encode all sorts of different squawks and bleets and growls. At about the same time, the mouth, which was already being used for both eating and breathing, began to take on yet another function. By shaping exhalations, the mouth became a versatile noise maker. So what we had was a powerful detector and a powerful effector residing almost by chance in the same head! And that made it possible for a grand new loop to arise.

For whenever the mouth squawked, the ear heard squawking noises. This was a very tight loop, a loop which didn't really involve the outside world. Not only was the detector wired to the effector, but the effector fed directly back into the detector.

One of the first consequences of this new loop, was that it became necessary to invent the concept of self. The ear had to learn to distinguish its own squawks from the squawks of its mother and brothers and sisters. It absolutely HAD to invent "me-ness" in order to survive and this was the beginning of both language and consciousness.

At first it was probably necessary to think aloud. The ear system sent encoded sounds directly to the throat muscles and then reacted to the sound waves that resulted. But then a few more neurons were added to the loop and it became possible to create a "computer model" of the the mouth, a system that could predict what noises would result whenever a certain code was sent to the throat and generate appropriate noise codes. Once this system was in place, it was possible to send signals around an even tighter loop: much more quickly and privately.

Meanwhile, a similar sort of thing was happening with the eyes. Like the ears, the eyes evolved from a simple light detector into a complex signal processor that could distinguish between and encode all sorts of shapes and colors. Just as an auditory processor arose to encode sound patterns, a visual processor arose to encode light patterns. And the "Language" of light is "Space".

As it turns out, we don't have the visual equivalent of a mouth, that is, an organ that projects visual images. But our entire bodies, and especially our hands, can produce spatial patterns and can also move the head and thus radically affect the eye's spatial relationship with the outside world. Thus our bodies can be a kind of visual mouth and speak, albeit less effectively, to our eyes.

(At this point, if you haven't already done so, you should examine the diagram underneath the reply boxes.)

The result is a somewhat weaker but still quite potent grand loop between the eyes and the body. Once again, an internal "computer model" arises, this time a model of our own body and its relationship to the world. Thus a more efficent internal feedback loop replaces the external feedback loop and we are able to "visualize" with our eyes closed. It should be possible, in principle, to think with the visual system by "imagining" symbols and then "seeing" those symbols with our eyes closed. Mathematics is sort of like that. Perhaps if evolution had taken a slightly different course we would be thinking with pictures instead of words.

This loopy view of the brain suggests, by the way, why reading and writing are more difficult than either speaking/hearing or moving/seeing. Reading and writing involve an extraordinary coordination between these two very different grand loops. It's not a hard-wired behaviour and thus it doesn't come naturally. Kids can learn to speak and see and move on their own (as long as there are things to see and words to hear). But they have to be taught in order to read and write.

In 1983 I made a journal entry on this subject in which I reached the following conclusion:

"Consciousness resides NOT in a central "CPU" unit but is based on the dedicated processors of the major sensory organs. It resides PRIMARILY in the auditory processor because the auditory system provides a natural feedback loop... We literally think with our mouths and our eyes and our ears and our hands!"

What does this have to do with reaction time based IQ tests? I'll tackle that one on my next card...