The Evolving Brain is stylistically an engaging and entertaining tour through a variety of contemporary topics in neuroscience, neurophysiology and related studies of the mind and brain. It covers a range of distinct yet related themes, ranging from basic neurophysiology to consciousness, which will be of interest to a broad spectrum of readers, providing a clear overview of the state of empirical research, and the conjectures that have arisen as a result of these discoveries.

R. Grant Steen opens the discussion, and sets the agenda, with an analogy which I immediately found annoying: comparing the functional and physical complexity of the brain to that of an anthill. Thankfully reference to this opening analogy is brief, and while I see the motivation behind some kind of (related) analogy, and perhaps appreciate its purpose as a means of making the subject matter more accessible it is, to my mind, unnecessary. That being said Grant Steen thankfully avoids the standard computer analogy — which, in a later chapter, turns out to be a result of certain claims about the brain being analogue, rather than digital — instead opting for something more organic.

The book carries the reader through the basics of neural anatomy, which I found both interesting and insightful, and of great benefit in later, more subject specific chapters. The information is presented clearly and effectively, with useful comparisons, decent diagrams and an air of competent instruction that is at no time monotonous or lacking in content.

Chapter 6, The Psychology of Learning, is particularly interesting, and spends sometime investigating types of Pavlovian conditioning, and relating conditioning to specific areas of the brain (that are now familiar thanks to the earlier chapters on neural anatomy). Some of the conclusions are frankly startling (at least to a layman), for example the claim that forms 'of learning that are motivated by fear require an intact amygdala' because the amygdala is a 'crucial locus of fear memory' (p. 120/121) may have interesting consequences both for psychiatrists treating people with post traumatic stress disorder, and for philosophers considering emotion and the mind/brain dichotomy.

The section within this chapter on language acquisition is also fascinating, and offers an insightful explanation of why adults insist on addressing newborn children in the hyperarticulated manner which most of us will be familiar with: the claim is that this infant specific dialect (with hyperarticulated vowels etc.) encourages language acquisition in children, and allows them to discern the differences in daily speech. By far the most interesting empirically based theories in this chapter are the links between memory (and learning) and i) sleep, ii) exercise and iii) (mental) training: in effect, by treating the brain as a muscle, training it regularly, and allowing for proper sleep — which allows newly acquired memories to become embedded — and physical exercise — which, in rats, has been shown to increase their neural development — we, as learners, can maximize our capacity to learn and acquire skills and memories.

In Chapter 7 Grant Steen goes on to articulate the neurobiology behind memory, which is so critical to learning, offering the reader cutting edge hypotheses about how and where different types of memory are stored in the brain. However, he does offer the caveat to his own explication of these hypotheses, stating that 'this description of the molecular events that occur during the formation of memory is a gross abridgment of an extremely complicated process, the understanding of which is still emerging' (p. 154).

One element of the book which I feel obligated to mention, simply to reiterate Grant Steen's own point, is the discourse which appears in chapter 8, and the potential benefits of neural stem cell research. Stem cell research is, as many people will no doubt be aware, the locus for much contemporary debate — specifically the (alleged) ethical dilemmas facing (local and national) governments and companies that decide to fund and engage in this type of research. The vital distinction Grant Steen makes is between reproductive cloning (which he, like most other people, is against) and research cloning (which he endorses), and he argues that the discussion needs to move away from a debate about the 'moral status of human embryos', which is, as he rightly points out, the current formulation (p. 182), and address the real issues of the potential benefits such research could deliver. There is, Grant Steen claims, a contemporary ignorance concerning stem cell research in this specific area (research cloning) that results in '400,000 blastocysts, which are produced by nuclear transplantation preparatory to in vitro fertilization [sic.], [being] thrown away every year in fertility clinics rather than being used for research that could benefit hundreds of thousands of people' (ibid). Given the potential benefits of this type of research (see chapter 8 of the book for some discussion of the applications of this type of research for things like Alzheimer's disease) which has nothing to do with reproductive cloning, it seems irrational to dispose of materials that could be employed in the (eventual) treatment of numerous neural disorders and diseases. Although this will certainly not be the end of the debate, Grant Steen's point is a good one, and well worth reiterating here.

As a philosopher the most interesting chapters were those on consciousness, altered states and emotions. What was perhaps most illuminating was the vast empirical literature available, and the definitions of the terms being employed by the various disciplines working on ostensibly the same problem. Consciousness, as Grant Steen readily admits, is a thorny problem for the neuroscientist, and because of its (seemingly intractable) subjectivity it is exceedingly difficult to study empirically (other than, one assumes, via testimony), and almost (if not actually) impossible to make accurate comparisons between test subjects. What impressed me most was the breadth of Grant Steen's philosophical view of consciousness, and the connections between the empirical discoveries cited in this book and the higher-order theories of consciousness discussed by philosophers such as David Rosenthal in Consciousness and Mind (2005) and William Lycan in Consciousness (1995). In effect I think that these chapters are emblematic of the need for interdisciplinary research and collaboration between philosophers, neuroscientists, psychologists and psychiatrists studying consciousness, and The Evolving Brain is certainly a valuable contribution to this ongoing research project.

Grant Steen goes on, in later chapters, to question, on the basis of empirical evidence, hypotheses such as the Whorfian hypothesis that 'thought is impossible without language' (p. 343) or the interconnection (and misunderstandings) between nature and nurture as it applies to social behavior. Finally Grant Steen's dismissal of Intelligent Design is also worth noting as he quite correctly points out that it (intelligent design) is not a theory with empirical evidence 'systematically organized to explain a broad range of facts', but is rather a 'stubborn refusal to consider the possibility of evolution' and is 'nothing more that a "just-so" story, devoid of intellectual content and lacking in any rationale save faith' (p. 386).

In short, although much of this book is concerned with "possibilities" and the "potential meanings" of a plethora of empirical investigations — indeed Grant Steen acknowledges, repeatedly, the limits of science and its ability to investigate, measure and interpret the information quickly being accrued about the mind and brain — it is an incredibly clear, wonderfully engaging tour de force through some of the most interesting aspects of the human brain, and its emergent mental capacities. Recommended reading for anyone who wants to discover what we know, what we think we know, and what we speculatively conjecture about the most complex organ of the human body — the evolving brain.

© 2007 Nigel Leary

 Nigel Leary is currently studying for a PhD at the University of Birmingham, working on the AHRC funded Metaphysics of Science Project. Broadly speaking his area of research is Natural Kinds as they appears both in post-Kripkean philosophy of language and in recent work in the philosophy of science and the metaphysics of laws. More specifically his research is focused on a metaphysics of mind question of whether Natural Kinds can be applied in any useful fashion to the problem of mental causation, and his intention is to argue that the mental can be causally efficacious.

Categories: Psychology