The Evolving Brain: The Known and The Unknown

The author of this book, a neurophysiologist in the field of psychiatry, has superbly described breakthroughs in basic neurobiology, debunked "intelligent design," and both argued and demonstrated the need for cross-disciplinary collaboration to address issues such as consciousness, creativity, and self-knowledge. Well written and informative, The Evolving Brain is recommended to a broad audience, including students wishing to gain an appreciation regarding how neurobiology can help address big questions in both normal psychology and in psychopathology, as well as established clinicians and researchers wishing to see the larger panorama within which their own focused work resides.

I personally found the review of basic neurobiology, from the action potential to emergent complexity, reinforcing in areas where I am knowledgeable (mental disorders and their biological correlates), informative in areas where I am less adept (computer modeling of mental processes), and refreshing throughout in its interdisciplinary breadth.

Paradoxically, given its title, the only area that I felt was not handled expertly was in its handling of how and why evolution had chosen us—Homo sapiens, with our large prefrontal cortex and our increased plasticity and capacity for learning and communicating—to be the rulers of planet Earth. Possible answers include intelligence, language, communication, theory of the mind, and activation of pleasure circuitry because of affiliative behavior—all lead to collaboration and sociality of our species.

But what external changes emerged 50,000 years ago allowing this to give us a selective advantage? Evolutionary theory itself has evolved, and this is not addressed. Specifically, whereas early models suggest that individual traits gradually take over because of their conferring an increased chance of procreating by their host, punctuated equilibrium argues convincingly that speciation confers stability, with new species emerging only when external factors throw ecosystems into disequilibrium. A clear example of this, supported by the fossil and geographic record, is the sudden end of the dinosaurs after a meteor hit Earth rendering it uninhabitable by dinosaurs and giving mammals a selective advantage. So what factors gave us, the intelligent afilliative communicator, a leg up? Did a planet lacking an adequate food supply select us because we, by virtue of our ability to collaborate, could hunt in tribes and follow game, as well as develop societies where agriculture and breeding of other animals could occur? I do not know. But I had hoped that Dr. Steen's book about the evolving brain would answer such questions.

Steen unequivocally delivers a slam-dunk victory for evolution over intelligent design. But I kept waiting for cutting-edge neurobiology and psychology to meet cutting-edge evolutionary theory, and this did not occur.

But, other than this, I found this book a tour de force. Paraphrasing Steen's closing sentence—"If great science is revolutionary, it follows that good science should be at least subversive"—the book is at least subversive.