The Structure of Intelligence
"Human Nature: a hopeful polemic"
Introduction
1. Chaos and Complexity
2. The Structure of Intelligence
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One primary attribute that clearly distinguishes humanity from other species, partisan snarking aside, is our intelligence. As such, an understanding of its structure and function is likely to be central to any description of human nature. Decades of research have been invested in the relationship between brain and intelligence, but I wish to call your attention to one recent book (courtesy Instapundit, around two years ago) which I consider to be incredibly significant. "On Intelligence" (2004), written by Jeff Hawkins with Sandra Blakeslee, introduces a powerful theory of the neurological structure of intelligence, and discusses the impact such a structure will have in the quest for artificial intelligence.
I find this book incredibly significant because I have come to believe that the memory-prediction framework at the heart of Hawkins' theory of intelligence is the primary piece in a set of rules which convincingly account for the entire spectrum of human thought, capability, and behavior. I STRONGLY recommend reading his very accessibly written book, but in order to provide necessary context I will attempt to briefly summarize the parts of his argument that are essential to understanding my own. (for the record, we have no affiliation, although I did send him an email alerting him to an early version of this post! Therefore, any and all mistakes are entirely my fault.)
In a nutshell, here's how it works.
Basically, your brain creates and then auditions pattern-recognizing models for their ability to sieve useful information from the torrent of incoming sensory data. This is what gives you the quick reactions you need to function in real time, in spite of the sluggishness of neurobiological processing speeds and the overwhelming volume of data.
The most successful models are reinforced and optimized, becoming dominant. Why? Because a model accurate enough to dependably recognize a repeating pattern essentially allows prediction of the completion of the pattern before it happens, which allows the brain to anticipate events, thus enhancing the chances of survival.
These predictive models are then layered to achieve more sophisticated predictions. Hierarchical layers are created when existing models are dropped below the threshold of consciousness, a process which automatically happens once they reach a sufficient level of predictive precision to become usable. Processing power then becomes available to construct new models. These learn to recognize patterns in the outputs of completed models, which have already been pushed down to the next level, and the process repeats. The deeper the stack, the more sophisticated its predictive capabilities are. Events not predicted by a given model are passed upward through the stack until they are accounted for, or until they reach your awareness.
You can't prevent this process any more than you can command your heart to stop beating. It's what your neocortex does. Hawkins maps this activity to specific neurological structure of the brain, and does a much more thorough job of developing this memory-prediction framework in his book than I can here. The gross oversimplification I am inflicting on his material is necessary in order to hold down the length of this post!
By way of a clarifying illustration, your ability to read this essay offers a good example of how this hierarchical layering works:
When you learned to read, you started by learning to recognize letters. Once your letter recognition models got good enough to become dependable, your brain started to use their output as the basis for constructing new predictive models that could recognize entire words. This is why it isn't necessary for you to consciously process every single letter when you read, although you can, if you focus your attention appropriately.
Extending the example, we can say that further modeling of phrase units, sentence structure, grammar, and composition are the subjects of yet higher layers, and your ability to coordinate the motion and focus of your eyes make up lower, older, more basic layers. Your knowledge of vocabulary and grammar actually allow you to predict what you will read before you finish each word or senten (see?) Hawkins argues convincingly that this predictive element is pervasive and central to the operating structure of intelligence.
The process works in reverse as well; if I wish to run up a flight of stairs, I start with a high-level prediction (running up the stairs) that propagates backward down the hierarchy of models that describe the correct sequence of muscle firings until it fires the appropriate individual motor neurons in the appropriate complex pattern, which is why I don't have to micromanage individual muscle movements while I am on the stairs. The better the models, the more natural and efficient the movement, and the deeper in the stack they are, the more unconscious your movements will be.
The expression "muscle memory" is often used to describe deeply learned complex movements, especially those of musicians and other performing athletes. The speed and relaxed precision of their movements are due to the layers of highly accurate models of body structure and function, integrated with equally well developed models of the execution of the task at hand, whether it's meeting a ball with a diving catch or playing a cello concerto from memory. The unconscious ease of a physical talent at work bespeaks entire subsets of accurate models pushed below the threshhold of consciousness, whether they were discovered quickly and "naturally" (a great definition of intuition!) or learned and refined more slowly and painfully through extended trial and error.
Interestingly, this same structure also provides an explanation for the phantom limbs sensed by so many amputees; the predictive models remain even when the limb is gone.
I'll leave you with one more tidbit: Hawkins also points out that because the patterns being recognized by these models are composed purely of neurological activity (sound, light, and touch already having been converted to nerve impulses before reaching the cortex), there is absolutely no difference between abstract and concrete concepts at this level. While "abstract" patterns can be harder to recognize because we have had far less experience in recognizing them than we have had in learning to operate our bodies, they are not handled any differently within the brain. This is an extremely important insight, and we'll come back to it later.
Now the above summary is merely a taste--there is much more to the book, including a much greater emphasis on mapping these functions to brain structure--but it should give the flavor of Hawkins' theory.
What can we do with it?
That will be the subject of the next chapter.
While I construct the next part of my explanation, I am posting what I have just written. Check back soon for more!