The Birth of the Mind: How a Tiny Number of Genes Creates the Complexities of Human Thought [Paperback]

It's a great pleasure to be able to highly recommend this book. I was suspicious of it because of the hype sent from the publisher, and the extremely broad topic covered for a science book, but it turns out that this is really good science writing. Gary Marcus certainly knows his stuff and has a distinctive talent for making complex things crystal clear. More, he has an infectious positive enthusiasm for scientific exploration.

With most popular science books about the human mind, the author tends to allow the material to be organized by their political and moral thinking. By that I mean the way the author thinks about human reason, autonomy, free will, and the essential nature of humans in general. So we most often have authors interpreting scientific data to show how the mind is: hardwired (or flexibly changing during our lives); highly specialized (or a general purpose problem-solver), built from adapted computational modules (or is essentially a useful artifact or "spandrel").

Each of these different ways of selecting and interpreting the data reveals a different way of thinking about ourselves. A hardwired, specialized, modular brain gives a very different way of thinking about ourselves than does an autonomous reasoning agent, and the implications for morality and for politics are profound. While cognitive science and biology are our greatest allies in the physical understanding of the world, when we try to rely on science to understand ourselves, we have been forced to speculate and extrapolate from them heavily in trying to get an accurate picture of humanity.

I bring this up to illustrate why Gary Marcus' "Birth of the Mind" is such a notable book. Somehow he manages to steer a course between the jagged rocks of innateness, the whirlpools of environmental determinism, and even the usual awkward compromises. Marcus celebrates the triumph of interactionism (genes plus environments) not by simply claming it to be true but by explaining exactly what it means and what it tells us. This is not a speculation about how genes and minds might be related; it is a carefully built skeleton of the conceptual bridge between the two. "Nature and Nurture" are not waved away here but deeply engaged. "Nature" here is not a collection of guesses about how we acted in the stone age and the challenges we faced in our evolutionary history, but an exposition of cellular biology and the way genes guide the construction of minds as a direct consequence of how they construct bodies.

This is a wonderful change from the polemics we find too often in books discussing research in genetics, evolution, and human behavior. Marcus isn't entering into one side of the technical debates on human nature here as we find in much of the popular sociobiology literature and popular behavior genetics literature. He isn't arguing about whether the mind is modular or whether it is a product of evolution. Nor does he argue about whether we have a soul or free will. As his title implies he is rightly more concerned about specifically HOW the mind arises, and this in itself hints at useful answers to the thornier questions. The tone of this book is simply that of shedding much needed light on the entrance to a long path to growing scientific knowledge of ourselves. Marcus appreciates both what we know and what we don't yet know about the mind, and that's an extremely valuable quality for writing about such a complex topic.

The spirit here is similar to that of Matt Ridley's recent book on nature and nurture. It is based on the emerging technical consensus that genes are central players in virtually all processes in living things, yet that genomes are not blueprints but self-regulating recipes. A relatively tiny number of genes is able to guide the development of brains consisting of an enormous number of neurons, and miniscule changes in the genome can produce dramatic changes in the outcome. Yet people with the identical genome have neither identical brains nor identical minds.

The solution to this dilemma is the centerpiece of the book, and it is answered by the way the genes work. They act as recipes, but as self-regulating recipes. This, Marcus explains, is the answer to the two great paradoxes of the mind: (1) a relatively small number of genes can reliably guide the self-construction of such complex multi-cellular organisms, and (2) the body is elaborately structured by genetic information yet still so flexible to environmental influences during development.

These are important and difficult questions that have great implications for our lives, so it is admirable that Marcus has addressed them without any obvious political axe to grind regarding human nature.

The book starts off introducing the hard questions: the surprising ratio of genes to cells, and the confusing mixture of stable and flexible developmental outcomes.

It then describes how we come out of the womb not with empty or fully formed minds, but as well-prepared learning machines with amazing and previously mostly unsuspected talents for observing and remembering in particular ways. The distinction between a brain that is "hardwired" and one that is "prewired" is the next topic. The brain has a definite structure, but one that is built for flexible change. Even identical twins, who share exactly the same genes, have different brain structure. When the crucial concept of the self-regulating genetic recipe is introduced, we see how the brain is built in exactly the same way as the rest of the body.

Next we see how genes guide the way neuronal connections are laid down: both how the brain is wired and how its structure is revised over time.

There is a single chapter focusing on human evolution, particularly on our capacity for language. Language has long been the classic example of a "modular" ability, but Marcus takes a different slant here, genetic rather than sociobiological. The evolutionary origin of language is used to show specifically how a small number of genes can have huge evolutionary consequences.

Although I found The Birth of the Mind by Gary Marcus to be a very well written book, I don't think that the author has added anything significantly new. Anyone who has read Penrose, Pinker or Dawkins is pretty much aware of the theory of mind as emergent property of brain function. Anyone who has kept abreast of research in genetics is aware that most of what we are as biological beings is dictated by our DNA. That the brain and the mind are part of that is hardly a surprise either. Of Dr. Marcus's illustrations of physical and cognitive dysfunction drawn from neurology and neurophysiology, few were new and most have been discussed in far greater detail in other volumes, the best known probably being Oliver Sac's The Man Who Mistook His Wife for a Hat.
What the author does do is put all of the most recent work together in a very cogent and readable manner for the average reader on the subject. His friendly, chatty writing style makes the subject very accessible. A youthful Associate Professor in the department of psychology at NYU, with a primary research focus in the brain and the mind in cognitive psychology, he is well placed to pull recent and germane literature together. For anyone who has read very little about the topic but who wishes to get a well rounded idea of the subject, this is a good place to start. It's current and well written even if the conclusions are not especially new.
For THOSE WRITING TERM PAPERS in psychology, history of science,or philosophy, this book might provide you with a large, very current collection of sources from which to begin your own literature search. Most of them come from 1995-2002. Among the list of periodicals are journals like the American Journal of Human Genetics, Brain Research, Cognition, Journal of Comparative Neurology, Journal of Neurobiological Science, Nature, the Proceedings of the National Academy of Science USA, and Science. Some of these, like Science and Nature, will be readily available in most college libraries and even some local public libraries, while others will only be available at large university, especially those associated with medical schools.

Marcus says, "From a mind's-eye view, brains may seem awfully special, but from a gene's-eye view, brains are just one more elaborate configuration of proteins."

This book is a compilation of very recent research about how the brain as an organ puts itself together. This process is not unlike the process for any other organ, but results in a product that is highly malleable and ripe for environmental adjustment. The book has been explained very adequately by many reviewers, so I will mainly try to provide you with some representative quotes and add only a few comments.

About Nature vs. Nurture:

"The nativists are right that significant parts of the brain are organized even without experience, and their opponents are right to emphasize that the structure of the brain is exquisitely sensitive to experience."

" At the core of our story has been a tension between the evidence that the brain can - like the body - assemble itself without much help from the outside world, and the evidence that little about the brain's initial structure is rigidly cast in stone.....To an earlier generation of scholars, the evidence for innateness and the evidence for flexibility seemed almost irreconcilable. Most scholars simply focused their attention on the stream of evidence they were more impressed with....Both sides have their points. The brain is capable of awesome feats of self-organization - and equally impressive feats of experience driven reorganization. But the seeming tension between the two is more apparent than real: Self-organization and re-organization are two sides of the same coin, each the product of the staggering amount of co-ordinated suites of autonomous yet highly communicative genes."

The above non-debate (to a hard science person) is well-covered, but the jist of the book is more about how the pre-wiring occurs, relying occasionally on computer science analogies:

"Each gene acts like a single line in a computer program."

"As soon as the IF part of the gene's IF-THEN rule is satisfied, the process of translating the template part of the gene into it's corresponding protein commences."

"With one more trick - regulatory proteins - that control the expression of other genes - nature is able to tie the whole genetic system together, allowing gangs of otherwise unruly free-agent genes to come together in exquisite harmony."

"Each gene does double duty, specifying both a recipe for a protein and a set of regulatory conditions for when and where it should be built. Taken together, suites of these IF-THEN genes give cells the power to act as parts of complicated improvisational orchestras."

How do the "billions of neurons in your brain" develop "trillions of connections between them." There is a well done scientific description given, but I also like his caricature description: "Even in a simple organism like a worm, the mechanics of (neuron) migration are so complicated they could have been borrowed from one of John Madden's playbooks. Cell number 1 goes right, number 2 goes left, and cell 3 goes long for a pass."

About language development:

" If language came onto the scene relatively quickly by evolutionary standards, it is because much of the genetic toolkit for building complex cognition was already in place."

"To understand the origin of language will be to understand how a relatively small set of new genes coordinates the actions of a much larger set or pre-existing genes."

"If language arose de novo, it would, I suspect, have to go through a long series of gradual steps, but if language arose by a novel combination of existing elements - such as neural structures for memory, the automatization of repeated actions, and social cognition - it is possible that it could have developed relatively quickly."

"A language module may depend on a few dozen or a few hundred evolutionarily novel genes, but it is likely to depend heavily on genes - or duplications of pre-existing genes - that are involved in the construction of other cognitive systems, such as the motor control system, which coordinates muscular action, or the cognitive systems that plan complex events."

There is lots more, including an appendix on methods for reading the genome, but I'll close with this quote from the final chapter: "In the coming decades, we will all - collectively , as a society - need to decide what we think about biotechnology and what applications we are and are not willing to allow. The debates we have now, about cloning and stem cell research, pale in comparison to debates we are likely to encounter as the technology for manipulating genes advances."

About a personal item:

When I was in school, I decided that I needed to study a concept an arbitrary number of times (say, 5 times), maybe from the different points of view of several scientific disciplines, in order to really learn it. I guessed that synaptic and neuronal pathways could be built up like bicep muscles. Marcus covers this and calls it "synaptic strengthening," along with a lengthy explanation that "More than a hundred different molecules may be involved, and there are at least 15 distinct steps in the process."

I highly recommend this excellent book.