TLS on Brain

on Brain

On The Right
by W.F. Bynum

a review of Iain McGilchrist's
THE MASTER AND HIS EMISSARY
The divided brain and the making of the Western world 597pp. Yale University Press. £25 (US $38).978 0 300 148787

In 1859, Richard Owen announced that he had discovered a unique structure within the human brain. This Hippocampus minor, as he called it, was so significant that it warranted a radical revision of the biological classification of human beings. Instead of sharing - as Homo sapiens - the same genus with the great apes, as Linnaeus had proposed a century before, we were now to have our own subclass, which Owen named Archencephala, by which he meant, "that which includes man alone". T. H. Huxley successfully challenged Owen's anatomical investigations, and Charles Kingsley immortalized the debate in his children's classic, The Water Babies.
In 2004, on his deathbed, Francis Crick, the discoverer, with James Watson, of the structure of DNA (1953), edited his final article, in which he and his co-author Christof Koch suggested that the claustrum, a sheet of neurons nestled between the cerebral cortex and the thalamus, might be the consciousness-producing conductor of the orchestra that is the brain.
These are only two of many examples of the search for the soul or whatever it is that makes us human beings. Neither features in Iain McGilchrist's far more subtle scrutiny of our brains and how they work. The claustrum does not even rate a mention, and the hippocampus is assigned its current neurological function as intimately involved in memory. (London cabbies apparently have well developed hippocampuses.) He wisely declines to confront the issue of consciousness head-on, concentrating instead on the myriad of mental capacities we possess, many of which we share with other animals.
read more McGilchrist himself is a psychiatrist with an earlier career as an English don, and he puts both of these talents to good use. Unlike Francis Crick, he also takes philosophy seriously, and although he protests that he is no historian, half of his book is historical: indeed, he views the whole of Western history through the lens of his primary concern with the human brain.
The essential facts of what is called laterality are well known. The left side of the brain controls the right side of the body. Most of us are right-handed, the speech centre is located on the left side of the brain, and therefore the left brain is generally called the dominant hemisphere. That a left-sided stroke or injury could cause paralysis or weakness on the right side was known to the ancient Greeks, and Paul Broca pinpointed the speech centre in the left cerebral cortex in the midnineteenth century, through autopsies on patients who suffered aphasia following a left-sided stroke. (Although Broca usually gets the credit, he was not even the first to show that the speech centre is in the left cerebral hemisphere.) Our brains do a lot more than merely allow us to talk and move, however, and during the past few decades, neuroscientists have used animals to elucidate the functional capacities of many parts of the brain. "Natural" experiments - injuries, strokes, tumours, congenital malformations - have provided neurologists with a good deal of information on which functions are associated with which brain structures, and McGilchrist uses both his own clinical experience and the extensive medical literature to good effect. It turns out, for example, that despite the fact that they can still speak, patients who have lost the use of parts of their right brains have even more difficulty adjusting to their disabilities than do aphasic patients who have suffered left-sided insults.
Modern magnetic equipment can neutralize the functional capacities of discrete portions of the brain, and this has provided a powerful, non-invasive way to examine, under experimental conditions, what happens when bits of the brain are briefly not working.
McGilchrist employs this evidence to argue that the right and left sides of our brains have different functions. One of the most powerful images in his book is that of chickens eating their food. The right eye (left brain) concentrates on the food at hand, while the left eye (right brain) keeps a scanning watch for predators or other dangers in their environments. The left brain is focused, rational and goal-directed. The right is concerned with the whole picture, the surroundings and the context.
McGilchrist's careful analysis of how brains work is a veritable tour de force, gradually and skilfully revealed. I know of no better exposition of the current state of functional brain neuroscience, even if his interpretations always bear a pronounced phenomenological bent. Throughout, he emphasizes the asymmetry between the two halves of the brain, and how this is reflected in different but complementary tasks. In birds, this means that the left brain makes sure that food is eaten, while the right brain tries to ensure that something else doesn't have a meal at the same time. For human beings, the left-right dichotomy is much more complex. The left brain is logical, precise and concerned with atomizing things within its ken. The right brain is softer, able to hold contradictions within its grasp at the same time, and concerned with wholes and context. The right brain performs the Gestalt functions so beloved of the branch of psychology that goes by that name. Our right brains process the duck/rabbit image that has been part of psychology for more than a century. We see either one or the other, but not both simultaneously.
Within McGilchrist's model, the right brain is also the source of many of the human characteristics we value: love, reverence, music, the experience of art or literature, affection, companionship. These and other psychological modalities are processed in the right brain and then presented to the left side of the brain, mostly through the corpus callosum, a structure of conducting fibres that connects the two cerebral hemispheres. As long ago as 1981, Roger Sperry shared the Nobel Prize for Medicine for his work studying the effects of splitting the corpus callosum in patients, an operation sometimes performed to control epilepsy. Sperry provided scientific evidence for the different functions of the right and left sides of the brain in his careful "split-brain" investigations. McGilchrist can call on these and more recent and imaginative experiments in his own exposition of brain functions. He has many suggestive things to say about the role of right-left imbalance in the genesis of various psychiatric disorders, such as schizophrenia and anorexia nervosa. He repeatedly reminds us that the two halves of the brain are connected, and that both parts must function in order for normal psychological processes to be carried out. In the "scientific" part of his substantial book, he drops hints of what follows, but a casual reading of it could leave the impression that he is a modern, up-to-date neuropsychiatrist, eager for the next experimental findings to be published.
This characterization of McGilchrist is probably accurate, but many of the subtleties of the first half of his book get lost in the second portion, in which he offers a reading of the whole of Western culture, as a battle between the right and left potions of the brain. Having already argued for the role of musical sounds in the origin of language, he contrasts the archaic world of Homer and the pre-Socratics with the more precise and abstract vision of Plato. Plato, with his ideal types, becomes one of the large cast of leftbrain dominated thinkers who have had a pernicious influence on the long trajectory of Western thought.
In this account, McGilchrist comments on many works of art, music and literature. He is most comfortable in three periods: pre-Socratic Greece, the Renaissance and the Romantic period. These periods, he argues, allowed the kind of balanced creativity that right-brain dominance permits. Philosophy, too, from Plato to Hegel is pretty much of a left-brain wasteland. He is especially hard on Descartes, in whose philosophical enterprise he sees parallels with the experience of schizophrenia.
The fact that one could set one's watch by Kant's daily mid-afternoon walks damns this great philosopher, whereas people like Hazlitt, who enjoyed skulking around at dawn and twilight, are to be admired. Bentham's love of precision and facts counts heavily against him; Claude Lorrain's mastery of colour and light places him with the sheep.
If people come in for praise or condemnation, so do epochs. McGilchrist tells us that Hegel's spirit is like an "unseen presence" through his volume. He interprets Hegel masterfully, and uses the Hegelian Geist to survey whole historical periods. The Renaissance allowed the right brain to flourish, whereas the Reformation turned out to be a bit of a left-brain disaster. For the most part, so was the Enlightenment, even if Samuel Johnson and Thomas Gray pass muster (Gray's 1750 "Elegy" is annexed to Romanticism).
Worst of all, though, was the Industrial Revolution, the ultimate triumph of materiality, exploitation and greed. It was, in McGilchrist's memorable phrase, "the left hemisphere's most daring assault" on mankind.
It has been downhill all the way since then, relieved only by some art, music and literature, philosophers such as Nietzsche, Heidegger and Max Scheler, and critics like Isaiah Berlin. McGilchrist agrees that people are better off materially, but this has been achieved at a high price.
These snippets, probably picked out by my left brain, hardly do justice to McGilchrist's achievement. The book has real power, sustained as it is by a disarming style and some good jokes. It is hard not to agree with his values: respect for nature, the cultivation of human relationships, the intense appreciation of great art, music and literature. Nevertheless, there are problems. First, McGilchrist's view of history is an unremittingly elitist one: 95 per cent of humanity (and their brains) do not get a look-in, except perhaps as greedy modern slobs. His Reformation is simply Luther posting his Theses and then seeing it all going awry. His French Revolution is the bloodbath of the few. E. P. Thompson's works could have enriched his account of the Industrial Revolution.
Second, McGilchrist's world is an intensely male one. He is good on the development of the infant and child brain, but anyone wanting some sense of gender differences in brain functions, or of women's place in cultural history, will need to look further. Women occasionally appear as patients or sufferers from anorexia nervosa, but he fails to engage with the research that is devoted to exploring differences between the sexes. Given the stereotype of women as more right-brain dominated (nurturing, emotive, concerned with context), this is a serious omission.
Finally, there is the problem of Heidegger. Heidegger's phenomenology underpins many of his views of brain function. McGilchrist rightly condemns fascism and Nazism as regimes based on all that he attributes to left-sided brain functions: rationality, ruthlessness, obsession with efficiency and utilitarianism.
Heidegger's allegiance to the Nazis does not necessarily invalidate his philosophical positions, but this disjunction ought to have been addressed here. Had McGilchrist done so, he might have found it in himself to forgive Descartes for looking out of his window and seeing his fellow human beings as so many machines.
Philosophy does matter, and the aggressive scientific materialism that McGilchrist decries may not be the answer to the human condition. On the other hand, matter may turn out to be all that we have. In the meantime, perhaps we should spare a thought for that quintessential philosopher of the Enlightenment, curiously marginalized in McGilchrist's book. Hume wrote brilliant philosophy, but, he tells us, when he finished writing his philosophy, he left his study and went out and was the sociable chap, which earned him the epithet le bon David. Maybe we should all strive to emulate him.