delanceyplace.com 11/30/12 - reverse engineering the human brain

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In today's selection -- the secret to understanding the human brain is to realize that it is not a logic machine -- in fact, it has a weak ability to process logic. Instead, it is a superb pattern recognizing machine. Armed with this insight, scientists across the world are racing to "reverse engineer" the human brain and vastly extend the powers of our own intelligence:

"There is now a grand project under way involving many thousands of scientists and engineers working to understand the best example we have of an intelligent process: the human brain. It is arguably the most important effort in the history of the human-machine civilization. ... Reverse-engineering the human brain may be regarded as the most important project in the universe.

"The goal of the project is to understand precisely how the human brain works, and then to use these revealed methods to better understand ourselves, to fix the brain when needed, and -- most relevant to the subject of this book -- to create even more intelligent machines. Keep in mind that greatly amplifying a natural phenomenon is precisely what engineering is capable of doing. ... In this book I present a thesis I call the pattern recognition theory of mind (PRTM), which, I argue, describes the basic algorithm of the neocortex (the region of the brain responsible for perception, memory, and critical thinking). In the chapters ahead I describe how recent neuroscience research, as well as our own thought experiments, leads to the inescapable conclusion that this method is used consistently across the neocortex. The implication of the PRTM combined with the 'law of accelerating returns' is that we will be able to engineer these principles to vastly extend the powers of our own intelligence. Indeed this process is already well under way. There are hundreds of tasks and activities formerly the sole province of human intelligence that can now be conducted by computers, usually with greater precision and at a vastly greater scale. ...

"My goal in this book is definitely not to add another quotation to the millions that already exist attesting to how complex the brain is, but rather to impress you with the power of its simplicity. I will do so by describing how a basic ingenious mechanism for recognizing, remembering, and predicting a pattern, repeated in the neocortex hundreds of millions of times, accounts for the great diversity of our thinking. Just as an astonishing diversity of organisms arises from the different combinations of the values of the genetic code found in nuclear and mitochondrial DNA, so too does an astounding array of ideas, thoughts, and skills form based on the values of the patterns (of connections and synaptic strengths) found in and between our neocortical pattern recognizers. As MIT neuroscientist Sebastian Seung says, 'Identity lies not in our genes, but in the connections between our brain cells.' ...

"Human beings have only a weak ability to process logic, but a very deep core capability of recognizing patterns. To do logical thinking, we need to use the neocortex, which is basically a large pattern recognizer. It is not an ideal mechanism for performing logical transformations, but it is the only facility we have for the job. Compare, for example, how a human plays chess to how a typical computer chess program works. Deep Blue, the computer that defeated Garry Kasparov, the human world chess champion, in 1997 was capable of analyzing the logical implications of 200 million board positions (representing different move-countermove sequences) every second. (That can now be done, by the way, on a few personal computers.) Kasparov was asked how many positions he could analyze each second, and he said it was less than one. How is it, then, that he was able to hold up to Deep Blue at all? The answer is the very strong ability humans have to recognize patterns. However, we need to train this facility, which is why not everyone can play master chess.

"Kasparov had learned about 100,000 board positions. That's a real number -- we have established that a human master in a particular field has mastered about 100,000 chunks of knowledge. Shakespeare composed his plays with 100,000 word senses (employing about 29,000 distinct words, but using most of them in multiple ways). Medical expert systems that have been built to represent the knowledge of a human medical physician have shown that a typical human medical specialist has mastered about 100,000 concepts in his or her domain. Recognizing a chunk of knowledge from this store is not straightforward, as a particular item will present itself a little bit differently each time it is experienced.

"Armed with his knowledge, Kasparov looks at the chessboard and compares the patterns that he sees to all 100,000 board situations that he has mastered, and he does all 100,000 comparisons simultaneously. There is consensus on this point: All of our neurons are processing -- considering the patterns -- at the same time."