Books about Brains and Machines

Phantoms in the Brain: Probing the Mysteries of the Human Mind, by V S Ramachandran and Sandra Blakeslee

This book has a bit of a split personality, both in terms of its structure and writing. How much this has to do with the fact that it has two authors I'm not entirely sure, but the effect was to undermine Ramachandran's credibility in my mind. This the first of his books I have read, and may not have been a good place to start. However, it was weak enough in some ways that it makes me less likely to want to read more.

The first half is pretty much what I was expecting: a set of interesting anecdotes about the experiences of the patients of Ramachandran and others, and how these have illuminated our understanding of the workings of the brain. We hear stories about amputees with phantom limbs (and how the latter have been removed), people who believe that their parents are imposters, patients who cannot see anything on the left side of the world. These stories are told compellingly (presumably Blakeslee's contribution), and the way they are connected to the science is generally convincing.

Of these, one of the more memorable examples was the woman who developed sexual feelings in her phantom foot. It turns out the parts of the brain that process sensory information for the feet are adjacent to those for the sexual organs (according to the Penfield map). Assuming that the latter brain area expands thanks to the sensory vacuum created by the missing leg, it seems reasonable to think that the feeling in the phantom limb might be a mixture between the two. This may also account for foot fetishes. Interesting.

The second half is much more speculative, with Ramachandran explaining his hunches about areas that, as yet, have little evidence to back up any particular theory. Having heard Ramachandran speak about the brain before, I was actually expecting to enjoy this section, but this did not turn out to be the case: mainly because I was simply not convinced by his arguments. An element of this, no doubt, was his inability to be clear about where he stood on the issue of God: the subject of one of his chapters. This I found slightly cowardly, as if he were trying to avoid alienating either the faithful or the athiest elements of his potential readership. I will come clean and say I fall into the latter camp.

More importantly, I was very disturbed by a section in which he first explained why scientists were rightly suspicious of thought experiments, and then proceeded to describe a truly terrible one. He suggests if you were color blind he might be able to get you to feel the sensation or qualia of red not by just knowing that light coming in has a particular wavelength but, by "hook[ing] a cable of neural pathways from the color-processing bits of my brain to the color-processing bits of your brain." He claims that, though far fetched, there is, "nothing intrinsically impossible," about this scenario.

But how would a color-blind person develop color-processing bits of the brain? Though we know the brain has an architecture that determines which bits are used for what general tasks, we also know that elements of the brain that are not used atrophy (like the sexual organs over-writing the bit of the brain previously allocated to the foot). For instance, those born blind do not have wasted visual cortices: this section of brain is devoted to the remaining senses. In fact, it could be argued that someone's inability to experience certain qualia is caused by the fact that they never developed the appropriate circuits in the brain to process that 'feeling'.

When reading sections that, to me, seemed so illogical, I wondered whether some dumbing down had occurred in order to make the book sufficiently 'popular' science. However, it feel it unfair to blame Blakeslee when, at best, Ramachandran went along with this strategy (if that's what it was). Don't misunderstand me: there was far more in it that I found sensible than didn't (and pretty much all of it was at least interesting). However, there were enough fairly major deviations from reason as I know it that it undermined my trust in Ramachandran's analysis.

Another weakness in the second half of the book was the explanation of Ramachandran's theory about the elements that make up consciousness. I won't go into detail about these elements because he didn't... and that to me was the problem. The definitions he gave were far too lightweight for my taste: the issue, for instance, of what 'the self' is in the context of an embodied creature was given just a paragraph of explanation, when the subject could easily fill a chapter of its own. Of course, that would be a different book, but a clearer elaboration might have convinced this reader in a way that the current version didn't.

For my blood pressure, I wish I'd read the just the first half of the book with his fascinating patient histories and experiments. The more speculative stuff might also have been interesting, but only if taken seriously and explained properly. If this couldn't be done for a popular science audience, then perhaps it should not have been included in a popular science book.

On Intelligence by Jeff Hawkins

I have mixed feelings about what I consider to be 'celebrity' popular science books: being big in Silicon Valley and having something sensible to say about intelligent machines are two different things. In my view, however, Jeff Hawkins has paid his dues and deserves to be taken seriously. Though there is a lot wrong with On Intelligence, I believe Hawkins central theses—that much of what we call intelligence is based on the ability of our neocortex to make predictions, that the function of the neocortex is basic across sensing and actuation, and that this function can be understood in a relatively straightforward way—are all correct. If we're smart, some of us in the machine intelligence and neuroscience communities will take up his challenge to work on filling out this new theory.

However, I fear that this book was as much about promoting Hawkins new company as really pushing neuroscience forwards. If so, it's done a great job.

The book's biggest flaw from my perspective is that it puts up several unncessary barriers for those of us who are serious about the subject. The introductory chapters, for instance, are both too aggressive and too defensive. On the one hand Hawkins slights the last 30 years of research into artificial intelligence and neural networks in a far-too-general way, and on the other hand he talks up his own contribution in a way that made me uncomfortable (maybe I've been based in the UK too long?). Even if he's right, it's not polite (or necessary) to say it in the way he does. I don't know whether the writing style reflected Hawkins personality or not, but he didn't come across as a terribly generous person. This has nothing to do with his theories, of course, but much to do with the digestibility of the book.

I also found that the book was just a little too popular-science to be useful at times. I wanted more examples of real research, more cases where the theory tied into the reality of what other scientists had found. I also wanted more diagrams and fewer handwaving explanations. I felt particularly cheated because at various times we were promised that the sparse bibliography was supplemented by more stuff on the book website. This claim gave the book an undeserved credibility, as there are a total of four additional references on that site (at time of posting), hardly enough to have been worth missing out of the original book bibliography in the first place.

That said, the thesis is consistent with what I know about the brain (I'm no neuroscientist), well thought through, and well explained (if in a way that is not very helpful technically). Essentially, Hawkins argues that as information comes in from the senses it is sorted into increasing levels of complexity as it rises up the layers of neurons that make up the neocortex. So, for instance, lines become shapes then faces then specific people as you move up the hierarchy. At the same time, feedback from above filters the information coming in, so that the lower levels are specifically 'looking' for particular things. So if you see the top half of your friends head and then the rest is revealed, you'll be predisposed to see the bottom half you're expecting.

The next issue is that, if you don't (see what you're expecting), the information will be passed up the hierarchy until some level does expect it: either that, or it forces a new memory to form (Hawkins believes this happens in the hippocampus). Finally, he argues that this hierarchical traffic can go both ways: you can think about what you see (going up), or you can see (and do) what you're thinking about (going down). There's more to it, of course, but that's the gist.

Hawkins is right in that, as far as I know, that no-one has expressed this as an overarching theory in this way before. And I've little doubt that he's basically correct. However, all the pieces of this puzzle have been floating around for a while, and most researchers are only given the opportunity to work on pieces rather than the big picture. I felt a little more modesty wouldn't have hurt.

But perhaps that's the Silicon Valley talking. The book had two things in common with a patent application: a constant discussion of novelty with a distinct lack of details that would make it useful as a point of research for other people's work. A mixture of "insanely great" with "I'd tell you but then I'd have to kill you," if you will. I'm sure Numenta, the company formed to take advantage of the new technology, will do extremely well from this book.

The latter sections vary, and should be treated with care. After convincing us of his neocortex idea, he exposes us to several predjudices about embodied intelligent machines (robots), and  dismisses the problem of interconnections between neurons as hardly worth discussing. (It's a hard problem, and—many believe—a dealbreaker for artificial brains of any size). On the other hand he says some sensible things about consciousness and creativity

Anyone serious about machine intelligence, or brains in general, should read this book. Unfortunately, there is another, better, book out there to be written that really ties together Hawkins thesis with the evidence that supports it and explains his model well enough so that we could all go out and work on it... as he claims he wants to encourage us to do.