Book Review - On Intelligence

This week's class assignment is to read a book and write a critical review of it, so here is mine.



←　This is the book I'm reading at the moment.

It is a science book written by Jeff Hawkins, a theoretical neuroscientist who first worked in Silicon Valley developing personal computing software and hardware, then later returned to his first love - neuroscience - to seek answers to the question of how that lump of matter in our heads determines who we are.

Since I am a cognitive scientist with particular interest in theoretical neuroscience, this book is especially relevant to me.  However, I would recommend it to anyone who is interested in understanding the details of how the brain works at at the neuronal level.

Hawkins opens by explaining how in his early years he came to work for a number of computing companies because he had been unable to find any place where he could pursue theoretical neuroscience.  There were people studying neuroscience, but he thought they were too focussed on the cells rather than the functions that they perform (cognition, intelligence, etc), and there were computer scientists and artificial intelligence researchers, but they were too focussed on the functions without paying any attention to how these functions could be occurring in an animal (via neurons).  Because there was no field of study that suited him, he applied for a job and ended up designing several pieces of pattern recognition software that were very popular and made his name.

With this under his belt, he went back to study neuroscience and eventually founded his own non-profit research facility, now called the Redwood Centre for Theoretical Neuroscience, where he continued to develop the theory of neocortex information processing that he has laid out in this book.  He now has his own company that aims to implement his theories of the neocortex in useful artificial intelligence applications - Numenta.

The theoretical part of the book starts by explaining why he believes the neocortex to be the seat of intelligence.  As far as our nervous systems are concerned, it is the cortex that differentiates us (the mammals) from the other animals (lizards, birds, fish, amphibians, insects...).  Animals with and without a neocortex are much the same in terms of their repertoire of motor behaviours; they run, jump, bite, chew, swim, etc.  However, Hawkins argues that it is not this kind of behaviour that exemplifies intelligence, but rather the more abstract and unobservable behaviours, like remembering the layout of the environment, planning actions that may not receive a reward for some time, or developing complex social relationships (not to mention language).  The neocortex does this by discovering patterns in the things that we experience, and sequences in these patterns, and then by using these sequences of patterns to make predictions about what we will experience.

The most fascinating part of the book is the middle few chapters, in which Hawkins goes into detail about how the pattern and sequence detecting could occur in the columns that make up our cortex.  It all comes down to hierarchies.  The environment is sensed by our eyes, ears, etc, and simple patterns are detected by low levels of the hierarchy (early processing in the cortex).  Then the next level of the cortical hierarchy looks at these and finds more complex patterns, and then the next layer does the same to find even more complex patterns.

Above you can see how one of these hierarchies could be understood in terms of function, while to the right you can see how neocortical columns can implement these hierarchies.

I actually read about this book a few years ago and wanted to get my hands on a copy at the time.  I am glad that I didn't though, because I have recently been doing a lot of research into hierarchical processing and learning in different parts of the brain (cortex, basal ganglia and cerebellum), and reading this book at this time in particular has provided answers to many questions that I have only just started asking, as well as guiding me towards many more questions that I would like to find the answers to from now.