The human factor

The Private Life of the Brain

Susan A Greenfield <em>Penguin, 249pp, £18.99</em>

ISBN 0713991925

The idea that the brain works like a computer is rapidly passing into intellectual history. Born amid the technological confidence of the Fifties and Sixties, it was based on the view that the brain was, in essence, an information-processing machine which somehow produced consciousness. This view was conditioned by the spectacular advances in artificial information processing that have been made over the past 50 years. After all, if computers could play chess, there seemed no clear reason why they could not do everything else.

This led to the conviction that we would soon be able to engineer artificial intelligence (AI) and possibly even self-consciousness in machines. Yet, in spite of the huge increases in the processing power and efficiency of computers, nobody has produced a machine with anything remotely resembling even rudimentary intelligence, never mind consciousness. The reason is that the computer model - proselytised by writers such as Daniel Dennett and Douglas Hofstadter - is plainly wrong. To see the human brain as an information-processing system is to omit all its most important features - the self, emotion, the whole paraphernalia of subjectivity involved in that unique and unprecedented entity known as me.

Now science writers such as Gerald Edelman, Terrence Deacon and, in The Private Life of the Brain, Susan Greenfield have decisively rejected the computer model. Their problem is that, as soon as you abandon that relatively simple idea, it is hard to know where to turn. Evolution is one answer - Deacon persuasively though speculatively argues for meat-eating and its consequent requirement for strong sexual pair bonding as decisive in the formulation of higher consciousness. Another answer is brain chemistry - which is Greenfield's speciality. But, for the moment, nothing is certain. Indeed, Greenfield confesses that, over the past decade, "it seems to me that we have not really moved forward at all".

In effect, the collapse of the computer model has sent us back to square one, and now every book on brain science seems like a new, tentative beginning. And yet, as Greenfield shows, although we lack a single convincing theory, we do have an immense amount of very sophisticated information about what the brain actually does. We can study the firing of neurons and the cascades of neurotransmitters and hormones, and we can, to some extent, link these to aspects of conscious experience. What these seem to show is an ever-changing ballet of interactions which seems to bear little relation to that most bizarre phenomenon of all - the sense of the continuity of the self over time.

"Such is the human condition," Greenfield writes, "an ever-changing symphony of the rational, the abstract, the general- ised, the personal with the sensual, the vivid, the new." Her own view derives from the idea that the most elementary form of consciousness is feeling. We don't have a computer in our skulls, we have a sensation organ. In the baby, this is all there is. In the adult, it is overlaid with memories, associations and valuations. But, in moments when the adult self is abandoned, we find ourselves restored to this primitive form of consciousness. Thus in dancing, sex, pain and, perhaps, in dreams and schizophrenia, we return to a childlike vision of existence as an overwhelming and uncontrollable landscape of sensation. The removal of the self gives us an inkling of its most primitive beginnings.

The establishment of the self becomes, in this view, a movement away from and a suppression of the brain's role as organ of pure feeling. As Greenfield notes, this tends towards the Freudian view of the self as a battleground between the demands of society and of instincts. However, she can provide evidence unavailable to Freud - the chemical cascades and neuronal interactions that are the weapons in this battle.

Greenfield does not claim that this theory is in any way conclusive; only that, in the future, it will be testable with improvements in brain imaging techniques. Furthermore, she is aware that she provides no real definition of the self. She can only say that she finds it "impossible to distinguish mind from the concept of self. After all, if mind is the personalisation of the brain, then what more, or what less, could self actually be? I'll stick my neck out and say that, as far as I am concerned, the two terms might as well be synonymous."

The attraction of Greenfield's approach is that she avoids the more obviously implausible simplifications that have so often discredited research into the mind. It is not "all in the genes"; indeed, other than creating the basic chemical constituents, it is hard to see the genes as being anything more than bit players in this drama. And the brain cannot easily be divided into specific areas responsible for specific responses. All the research now suggests that brain activity is remarkably holistic in that it can involve seemingly random firings of millions of neurons at a multitude of locations. Flash a light in your eye at one moment and it will produce an entirely different sequence to a subsequent flash a moment later.

The picture that emerges of the mind is of formidable complexity which can be understood only as complexity, not merely as the iteration of some simple algorithm. This, it seems to me, is a more humanly persuasive picture than anything that has gone before. We don't feel easily reducible, and that alone should have been enough to warn the AI fanatics that they were barking up the wrong tree.

There is, however, one quite serious criticism to be made of this book: Greenfield cannot write. Her prose lacks any sense of pace and rhythm, and her attempts to jolly us along are painful. There is no reason why she should be able to write well - it is her science that matters. But, on the other hand, if Penguin is seriously aiming this book at the common reader, then why on earth did they not find a literate editor to clean up its multiple infelicities? British publishers seem to have lost or abandoned this creative editing function. This is unfortunate because, as a result of Penguin's inaction, although Greenfield has much to say, she has little chance of being heard.

Bryan Appleyard's most recent book is Brave New Worlds: genetics and the human experience (HarperCollins, £8.99)

This article first appeared in the 05 June 2000 issue of the New Statesman, Driving back to happiness