How Brains Think: Evolving Intelligence, Then and Now (Science Masters Series) by William H. Calvin

Product Details
Amazon Sales Rank: #504675 in Books
Published on: 1997-09-01
Number of items: 1
Binding: Paperback
196 pages
Editorial Reviews

Amazon.com
William Calvin, a neurophysiologist and author of The River That Flows Uphill: A Journey from the Big Bang to the Big Brain, attempts to reclaim the study of human consciousness from physicists like Roger Penrose. Physicists, Calvin suggests, reduce the mind to subatomic particles and mathematical equations, whereas those in his specialty see the seat of consciousness and intelligence in higher levels of brain physiology--the neurons, synapses, and cortex. Calvin is a Darwinist who regards the unique level of human consciousness as the product of evolutionary forces that began with the ice ages two million years ago. The human response to this natural threat, he argues, was to develop mental faculties that allowed high-level communication and, thus, cooperation, leading to complex language capabilities and the distinguishing human characteristic of abstract thought.

Sunday Times [London], 1997
"Calvin is fizzing with ideas and this is a provacative, stimulating book."

The New York Times Book Review, Marcia Bartusiak
... an exhilarating intellectual journey ... [Calvin is] a member of that rare breed of scientists who can translate the arcana of their fields into lay language ... lyrical and imaginative in his presentation.
Customer Reviews

A Review of How Brains Think
Calvin contends that brains (OR COMPUTERS!)
are able to THINK by virtue of being "Darwin
machines," machines that emulate biological
evolution but on a much reduced time scale.
Calvin's Darwin machines possess six essential
properties:
1. Patterns are recognized and manipulated.
2. The patterns are copied and
3. modified.
4. Patterns are evaluated during their use
and compete for limited storage space.
5. The values assigned to the respective patterns
measure their success when used to control actions
of some agent in an environment.
6. The best patterns are retained for future
reuse while poorer ones are discarded.
Calvin attempts to show how these 6 processes
might be obtained with realistic biological
neural networks. I found these latter arguments
to be incomplete and unconvincing. To be fair
Calvin refers the reader to another of his books
THE CEREBRAL CODE for a more detailed discussion.
I need to read that book but have yet to do so.
I do believe, however, that modern artificial
intelligence software does qualify as a Darwin
machine according to Calvin's criteria (see,
for example my Asa H, Transactions of the Kansas
Academy of Science, vol. 109, No. 3/4. pg 159,
2006, R. Jones)

What to do next?
Calvin offers an evolutionary description of the development of human intelligence. He's very careful to avoid using "consciousness" since Dennett, Humphreys, Pinker and others have firmly employed that term. Calvin cites Piaget's "intelligence is what you use when you don't know what to do next" as a foundation thesis. From this he compares human mental talents with those of other animals, mostly primates, to demonstrate evolutionary roots for our intelligence. Behaviour issues common to everyday life become visible evidence for what is going on in our brains. Calvin manages to take his analysis into the physical processes that occur as we decide on our actions. It's a well written and "down to earth" explanation of many questions we have on what intelligence is and how we use it.

Piaget's comment reflects the growing knowledge of brain processes. Much of the brain's time is spent collecting, storing, retrieving and applying information. This means that both "unconscious" events and our expressions and actions only come about after numerous and complicated signal processing has already occurred. Calvin describes in both text and graphics how neurons are constructed, convey data, and interact within the brain. Clearly, nothing is instantaneous and many elements are competing for dominance during every moment awake. Clear, too, is the notion that while other primates have many talents to deal with their surroundings, none possess the powers evolution gave humans.

What drives these powerful mental abilities? He rebuffs the idea of the "quantum brain". It's too deep in the brain's structure - "in the subbasement of physics". That's too far removed from areas of vision, speech, and memory. There are certainly quantum events going on with all that chemical and electrical activity inside your skull, but Calvin sees these forces as far to deep to have direct impact on mental processes. Calvin is more concerned with the human level of analysis. One proposal he adopts wholeheartedly, but without attribution, is Daniel Dennett's concept of the "multiple drafts model" of thinking and expression. Calvin, to his credit, outstrips even Dennett's abilities of description in depicting this process. He shows, for example, how the brain's memory storage facility considers many images before it resolves that the round thing flying past is a tennis ball. It's an exquisite example, and you perceive clearly how many other daily occurrences are resolved in a similar manner.

The accumulation of evidence about our evolutionary roots, the environmental changes forced on us and the rise of language and use of syntax are all contained within a device Calvin labels the "Darwin Machine." The Machine has six "essentials" which cover topics like replication, mutation and success in adaptation. He demonstrates how the "essentials" provide a mechanism for complexity from simplicity. Where some creatures modified things like limbs, teeth or hair, it was our brain that evolved from simple to complex.

While evolution of the human brain isn't a new topic, Calvin presents a better summary of its roots and operations than most cognitive scientists. This is a fine book to start any study of the brain, but must be enhanced by other, more complete, works. [stephen a. haines - Ottawa, Canada]

Calvin's Neocortical Darwin Machine
This book is an attempt to "pull together all of the essentials.....of a darwinian process" and "describe a specific neural mechanism that could implement such a process in primate neocortex." Calvin is an advocate of the idea that brain-based darwinian processes are what provides brains with what we call "consciousness" and "intelligence". The first six chapters do the pulling together and chapter seven presents the proposed mechanism. Chapter 8 explores implications of darwinian brain processes for artificial intelligence.

As we plod along towards Alan Turing's dream of constructing intelligent machines, there are a few road-blocks we need to get around. Calvin mentions that any explanation of biological intelligence ought to have implications for artificial intelligence. He admits that, "the ad-hoc schemes of AI might also produce intelligent robots", but he clearly likes the idea that the most efficient path to intelligent man-made devices that can duplicate human mental abilities (what Calvin quaintly calls a "workalike") is to learn the essentials of how biological brains work and then apply those principles to the problem of making a workalike. One road-block is the fact that so many AI researchers ignore the task of reverse engineering the human brain or, at best, they assume that what was known about brains in the 1940's is enough. Unfortunately, I doubt that Calvin's hop-skip-and-jump over this issue will move any AI researchers away from their "ad-hoc schemes". Even AI researchers who like the idea of evolutionary processes pay little attention to the idea of adapting the physiological mechanisms of biological brains to evolutionary computing.

A second road-block is the distinction that is usually made between hardware and software. Turing was among the first to recognize how to use electronic devices to implement the power and beauty of this distinction, and most AI researchers remain devoted to hardware-software duality. Unfortunately, biological brains were not designed by an electrical engineer. It thus becomes a danger that biologists will mistakenly attempt to make sense of biological brains by looking at brain processes through the distorting lenses of hardware-software duality. I think that Calvin gets caught in this trap of dualism and it deflects him from paying close enough attention to the details of how biological brains really work.

Calvin's dualistic thinking starts with the harmless division of brain processes into two types, those that depend on "cerebral ruts" (hardware) and those that dance more freely through the brain and so are able to function like "software".....Calvin usually calls these "firing patterns". The dangerous step comes when Calvin suggests that the pattern of action potentials in any particular neocortical minicolumn can be replicated and spread through the cortex like a piece of software code and be "played" on the millions of other minicolumns in the same way you can play a million copies of a CD on a million CD players......the key difference being that while all CD players are designed to do basically the same task, the various cortical minicolumns can all have their own unique "ruts" and the copies of the firing patterns are not exact duplicates. This allows for a "cerebral symphony" rather than just a million-fold amplification of the same tune and a "survival of the fittest" process whereby those firing patterns that resonate best with the existing pool of "ruts" will dominate our consciousness and generate intelligent behavior.

Allegorically, this is an appealing model of cortical function, and the sort of evolutionary mechanism that AI researchers like to build into computers. Unfortunately, biological brains were not made by engineers. Where does Calvin go wrong?

For Calvin, "copying" is the essence of darwinism, but people such as Stuart Kauffman (see his, "The Origins of Order") and Freeman Dyson (see his, "Origin of Life") have long ago made the point that evolution does not REQUIRE copying. Life as it now exists involves molecular replication, but that is just a special trick that proved useful for living organisms. Life probably had an initial "metabolic" period without molecular replication. George Dyson (in his book, "Darwin Among the Machines") has pointed out that man-made machines (such as industrial robots) can evolve without replication.

Is there another way that evolutionary processes might exist in biological brains without the emphasis that Calvin places on copying? Gerald Edelman's theory of "Neural Darwinism" (see his book by that name) provides an alternative to Calvin's emphasis on copying. Anyone who reads Calvin's theory (chapter 7) should compare it to Edelman's theory. My guess is that Edelman provides a better framework for thinking about evolutionary processes in biological brains, but Calvin's theory is more accessible and "intuitive", so it may be better as an introduction to the importance of evolutionary processes in the brain.

Calvin does not dogmatically push the "darwin machine" mechanism described in chapter 7, and, in fact, seems to invite people to simply skip that chapter. He devotes considerable space (particularly chapter 3) to discussion of trying to find the level of detail required to find the essence of how biological brains produce consciousness and intelligent behavior. I suspect that Crick (in his "The Astonishing Hypothesis") and Edelman are closer to identifying this critical level, with Calvin just a bit too reluctant to delve into the details of how synapses work. Although Calvin does touch on the function of synapses briefly in chapter 7, he spends considerable space clumping the study of synaptic learning mechanisms in with quantum consciousness theories as examples of inappropriate attempts at reductionism. But even if Calvin has slightly missed the mark, he provides an accessible account of why it makes sense to continue trying to identify and elucidate evolutionary processes in the brain.