Thursday, October 19, 2006

On Intelligence: Hawkins HTM computational theory

I LOVE blogging.

Two days ago I made the FYI post "Brain boss (prefrontal cortext) acts in step-wsie manner?" Shortly thereafter, someone posted a "comment" suggesting a link between the sequential step-wise hypothesized functioning of the prefrontal cortex and Hawkin's (2005) Hierarchical Temporal Memory (HTM) computational theory of intellectual functioning (as outlined in his book "On Intelligence"). I had never heard of this book or theory.

What I find intriguing is the fact that Hawkins is no minor player on the modern technology stage. He is well known for a number of activities--namely, he has founded founded three companies: Palm Computing (who has not heard of Palm Pilots?), Handspring, and Numenta, and the non-profit Redwood Neuroscience Institute, a scientific research institute focused on understanding how the human neocortex works.

The typical reader of IQs Corner may be wondering why someone with his background is now dabbling in understanding human intelligence. I wondered this myself. The answer lies in the Prologue to On Intelligence. A portion is reproduced below.

Maybe some readers of IQs Corner will explore this area in greater detail
  • You may be wondering why a computer designer is writing a book about brains. Or put another way, if I love brains why didn't I make a career in brain science or in artificial intelligence? The answer is I tried to, several times, but I refused to study the problem of intelligence as others have before me. I believe the best way to solve this problem is to use the detailed biology of the brain as a constraint and as a guide, yet think about intelligence as a computational problem—a position somewhere between biology and computer science. Many biologists tend to reject or ignore the idea of thinking of the brain in computational terms, and computer scientists often don't believe they have anything to learn from biology. Also, the world of science is less accepting of risk than the world of business. In technology businesses, a person who pursues a new idea with a reasoned approach can enhance his or her career regardless of whether that particular idea turns out to be successful. Many successful entrepreneurs achieved success only after earlier failures. But in academia, a couple of years spent pursuing a new idea that does not work out can permanently ruin a young career. So I pursued the two passions in my life simultaneously, believing that success in industry would help me achieve success in understanding the brain. I needed the financial resources to pursue the science I wanted, and I needed to learn how to affect change in the world, how to sell new ideas, all of which I hoped to get from working in Silicon Valley.
  • In August 2002 I started a research center, the Redwood Neuroscience Institute (RNI), dedicated to brain theory. There are many neuroscience centers in the world, but no others are dedicated to finding an overall theoretical understanding of the neocortex—the part of the human brain responsible for intelligence. That is all we study at RNI. In many ways, RNI is like a start-up company. We are pursuing a dream that some people think is unattainable, but we are lucky to have a great group of people, and our efforts are starting to bear fruit.
  • The agenda for this book is ambitious. It describes a comprehensive theory of how the brain works. It describes what intelligence is and how your brain creates it

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1 comment:

Dox O'Ryan said...

You mentioned Jeff Hawkin's HTM theory. His book made me wonder (among other things) about the "shape" of memories and how that might affect thinking. My recent blog post at does some public wondering about that. It's copied below to avoid anyone clicking away. Any thoughts on the question?:

On Intelligence II: Does Hierarchy Shape Matter?
In my first entry on Jeff Hawkins' On Intelligence, I said it became a filter for an unbelievable number of the things I notice and wonder about...and yet I haven’t added new entries about it. Truth is, it's mostly because I fear it may seem so bizarre to use a single set of ideas as a filter for so many things, that you'll find my selection of blog topics even more oddly random than you already do. But it's time. To kick it off, I'll briefly mention step 1: The Hawkins Memory-Prediction model of the brain focuses on hierarchy. Ignoring the details, parts of your brain get information (typically from the senses) and if it matches what they expect, they do nothing. If it doesn't, they pass the information up the hierarchy. It's sort of like an entry-level worker escalating a new problem to his or her boss. And like the CEO (which, in a sense, you are), you don't have time or mental cycles to stay on top of what's happening at the low levels in the hierarchy, so you generally keep track of what's being passed up the chain. You could say, "Your brain--and therefore, you--only notice something if it differs from expectation." Simple, elegant, and able to explain many of our perceptions.

OK, step 2. The more accurate the predictions are at the lower levels of the hierarchy, the less they have to pass upward. How do the predictions get more accurate? By experiencing information more often, predicting something, and checking results. Practice makes perfect. They get "smarter." Suffice to say this works identically for observing something--as in knowing immediately whether a dirty, brown rock is a clump of dirt, a piece of quartz, or a diamond OR for doing something--like playing a sonata on a violin or designing a brilliant ad for a new soft drink (is there such a thing?).

Step 3. If a talented person spends 18 hours a day playing the violin, the violin-connected parts of their brain will be very smart. The lower levels of the hierarchy won't need to escalate messages often. When this happens, the theory claims, the upper levels of the hierarchy don't just take a vacation. Instead, they think higher thoughts. They look for connections between the things the lower levels are doing. It's like a lucky manager leading such a great team that she gets to spend time focusing on long-term strategy, integration between functions, or new ways to think about everyday tasks. The hierarchy of the dedicated violinist becomes very "deep." It has many levels because what is complicated and "escalated" one day becomes rote and simple the next. Of course, our master violinist will probably be a lousy diamond finder.

Now things get interesting (at least for me ;-). Imagine another person who is a dilettante. He dabbles in a thousand things, paying attention in the moment, but gaining no expertise. The theory would say his brain is constantly passing messages upward. Little is rote. The lower levels have mastered little, so escalation is the norm. You could say this person's brain hierarchy is extremely flat. Poor guy, right? But along the way, he is certainly creating connections and, if the theory is right, his dabbling brain is still making constant predictions. And he's really fun at parties. And since the brain doesn't "know" when it's playing the violin and when it's looking at dirty rocks, it seems clear that experiences in one field will start to inform predictions in others. I'm not speculating that if you look at enough rocks you'll be able to play the violin. But if your brain only has random data, it's going to use it the best way it can.

So here's my quandary: Of these two people, who would you trust to build your kid a treehouse? Or set up your Tivo? Or make you dinner? Or join your bowling team?

If you had them both on your team doing something neither had done before, would you assign them to different types of tasks?

Too ridiculous a question? Ok, then how about just this: What would you encourage for your child? What do you wish was encouraged for you when you were young? (Assuming this sort of thing can be encouraged at all.)

Will a flat hierarchy drive more diverse connections and relationships? Will a deep hierarchy--more practiced in "thinking about thinking"--provide more abstract, in-depth considerations in other fields?