This is a wonderful book which I heartily recommend to
any interested readers who want to explore either genomics or the workings of
the mind/brain.  In fact, I loved this book and think that many readers will
view it similarly.

   Throughout the book, which is
written for reasonable well-educated lay-readers, Marcus points out the
misconceptions which are rife in most peoples’ views of genomics and especially
psychogenomics and explains how just 30,000 genes can and do encode the
incredibly complex brains of human beings, with billions of neurons and
trillions of neuronal connections.   He makes the major point that "what
is good enough for the body is good enough for the brain", and that the
genes which build the body overlap with and work in the same way as the genes
which build the brain, using many examples throughout the book from ocular
dominance columns and other areas.

   In nine short chapters he
covers a great deal of ground, and the chapter titles themselves keep us
reading – "Born to Learn", "Brainstorms", Aristotle’s
Impetus", "Copernicus’ Revenge" and "Paradox Lost",
among others.

   He begins with a quote from
Richard Dawkins:  "The genetic code is not a blueprint for assembling a
body from a set of bits; it is more like a recipe for baking one from a set of
ingredients.  If we follow a particular recipe, word for word, in a cookery
book, what finally emerges from the oven is a cake.   We cannot now break the
cake into its component crumbs and say:  this crumb corresponds to the first
word in the recipe; this crumb corresponds to the second word in the recipe,
etc."  Genes "work" with one another, and they have major
interfaces with the environment as well.   Thinking and behavior are not
completely determined by the genes, which are necessary but not sufficient
conditions.

   Marcus uses MIND rather than
BRAIN in his title, but immediately cites Pinker’s definition of mind as
"what the brain does."  He is a fan of Crick’s fascinating book, The
Astonishing Hypothesis, so this is not a dualistic book, and the author
dismisses dualism without really considering its arguments.   He extends
Crick’s thesis, arguing that the mind has its origin in the brain, and the
brain has its origin in the genes, and he points out that consideration of
genes has been very deficient even in recent work on theory of mind.  At the
same time, he is very careful to point out that genes do not control our
destiny – they contribute importantly, as do all kinds of internal and external
environmental factors.

   After this introduction, Marcus
turns to the question of the mind/brain of human neonates and argues about what
is encoded and what is plastic.  He next turns to the structure of the brain
and its flexibility.  He provides a wonderful description of genes and proteins
and develops the concept of "genetic recipes".   He argues well that
the role of genes in the brain is the same as in all other organs.  He moves on
to the interaction of genes and the environment in brain function – an
excellent and well-informed discussion.  He follows with a wonderful chapter on
evolution which clarifies more than anything I have read why, with 98.5%
genomic similarity to chimpanzees, human beings are so different.   Finally, he
argues that vague concepts such as "nature and nurture" are truly on
the verge of being replaced by "a synthesis of biology and the cognitive
sciences".

   Throughout the book, he
downplays a special role for genes in the brain vs other organs, and he is very
convincing.  "In fact, I use the term ‘mental gene’ as a bit of a joke.  Although
many genes affect our mental life… ‘mental genes’ are pretty much the same as
other genes:   self-regulated instructions for building parts of a very complex
biological structure… Many of them … are the same.  From the perspective of
the toolkit of biology, there is little difference between a gene expressed in
the brain and a gene expressed elsewhere.   A gene is a gene is a gene." 
And this, for Marcus, is an organizing principle.  Our genes lead to our sense
of self, and our sense of self realizes that it shares its genes with others
throughout the animal kingdom:  he (and I) find this unifying, gratifying –
solace, in fact.

   The chapter on evolution is the
heart of the book, in some ways, and a truly outstanding discussion.  Our genes
add to survival value by making our brains and our selves flexible enough to
adapt and care for ourselves.  Marcus considers many important topics but has
an especially fascinating view of   the role and place of language in our
evolutionary development, which is central, crucial, and certainly imperfectly
understood and still very controversial.  The author presents the arguments of
Fodor, who believes that formal language is distinct from a "language of
thought" in the brain, and Gleitman, who points out the lack of cognitive
differences in people who speak different languages and argues that a
pre-existing conceptual component of the brain produces what we view as
language as its mental representation.   (There are many opposing arguments
about this issue, of course.)  Marcus points out that the "genes for
language" reported by the media are not unique to language, and that our
"language genes" do not just come from the 1.5% of genes we do not
share with chimpanzees but from the other 98.5% as well.   He also makes
explicit the roles of many genes in determination of mental traits and
downplays the idea that we shall find one gene for depression, for example.

   He provides a very brief but
fascinating overview of real and potential ethical issues, especially in regard
to "designer babies".

   Marcus provides an excellent
appendix providing interested readers with a good account of methods used in
genomic research – an excellent introduction to this topic.  There is an
outstanding glossary, seventeen pages long, defining common terms of molecular
biology and genomics for the general reader.   The chapter notes which follow
are useful and are annotated in many cases.  There are thirty pages of
references which really provide a major resource for scientific and medical
readers who wish to pursue the book’s topics in more detail.

   I cannot find any significant
aspect of this book to criticize.  It is well written, and the author has a
sense of humor, which can be very helpful in a book like this.  For example, he
alludes to a "study" allegedly finding that human infants are stupid,
which is a wonderful, satirical piece in The Onion.   He realizes that psychogenomics
is in its infancy and makes an occasional delightful comment such as,
"Scientists are a lot better at ‘finding’ genes for complex mental traits
than they are at replicating their findings."  This is a superb book, and
I recommend it most highly.

© 2004 Lloyd A.
Wells