As a junior medical student I walked the waxed, antiseptic-smelling corridors of Sydney’s Royal North Shore Hospital dressed in an oversized lab coat. One of the first patients I was encouraged to see was a middle-aged woman from the Central Coast. A retired schoolteacher, she had been transferred after an unusual heart attack. As I began my examination, I felt an atypical collapsing pulse on her wrist, and remembered that the textbooks called this a water hammer. When I placed my stethoscope on her chest there was a rapidly rising and falling whoosh across the left side of her sternum, the aortic area of the heart. She had a damaged valve in an uncommon location.
But before I heard the so-called heart murmur, a term that made me think of bodily organs whispering sweet nothings, it was clear, even to a novice, that something else was unusual. When I asked her to remove her hospital gown, she did so with great enthusiasm, revealing her droopy, ageing breasts. I was taken aback, not yet accustomed to the power of my professional status. I felt awkward standing next to her husband, who muttered dryly, ‘How come you’re never like that with me?’
I mentioned the experience to one of her treating doctors, more as an amusing anecdote than because of any clinical significance. Although the registrar laughed, something also clicked and he ordered a barrage of tests. A week later he told me that my encounter had led to the discovery of a tiny lesion in the frontal section of her brain, perceptible only on expensive MRI scans. It was probably the result of a small stroke that occurred around the time of her heart attack. Barely perceptible, it had subtle effects on her interactions, particularly her social inhibitions.
I remember the episode clearly, even though it was early in my training. It focused my interest on our essentially social nature - how the vast bulk of our brain exists to process and react to social information; how primed it is to recognise, interpret and respond to the input of others, which lays down patterns governing behaviour. I have always been interested in the extent to which we are individual or collective beings, and how feeling is as fundamental as thinking.
In the decade and a half since that consultation, the study of the brain and how it regulates behaviour has become one of the most fertile fields of discovery. Barely a week goes by without a declaration of the relevance of neuroscientific findings to everyday life. A picture of a brain scan in pixel-busting Technicolor usually accompanies these proclamations, often connected to announcements from new disciplines with the prefix ‘neuro’.
Neuro-marketing allows advertisers to pinpoint the parts of the brain that light up in response to particular products or tailored messages. Neuro-economics looks at how we make economic decisions and their relation to brain functioning. Even some philosophers have embraced neuro-ethics, in which ethical principles are examined using brain scans to determine people’s moral intuitions when they are asked to deliberate on classic dilemmas. France has become the first country in the world to devote a government department to looking at the policy implications of our burgeoning knowledge of neuroscience, led by Associate-Professor Olivier Oullier.
My own field, psychiatry, has benefited enormously. While the specialty was once the bastard child of medicine - lacking prestige and credibility - a growing interest in mental health and the way brain chemistry affects our emotions has lifted it into the mainstream. During the 2010 federal election Australian of the Year Professor Patrick McGorry and the Brain and Mind Institute’s Professor Ian Hickie became two of the most prominent doctors in the country. While this goes some way to making up for years of neglect, it also suggests a growing expectation of a marriage of the biological and social sciences.
In my lifetime, three and a half decades, more has been learnt about the brain than in the whole of human history. We now know there are more than one hundred billion nerve cells, and each of them has many thousands of synaptic connections - channels of chemical communication - with its neighbours. We know an increasing amount about the anatomy of the different functional centres that make up the brain, their varying responsibilities, how they execute their duties and even how they evolved. We are beginning to understand how memory, which lies at the core the subjective self, is dependent upon the strength of the cell networks formed by our experience, thoughts and feelings.
We could even be on the verge of a new Enlightenment - one in which the concept of the individual autonomously making rational decisions is usurped by a new, more complex understanding of the forces that shape human nature. This process may be accelerated by the global financial crisis and the frailties of our systemic assumptions that it exposed.
It is rare to hear about human nature in discussion of politics, yet it is the foundation of the underlying conflict. Debates about human nature have often been restricted to criminality and other social pathologies, as if only bad people failed to conform to the behavioural model of modern economics. But most policymakers agree that whether addressing business regulation or competition in schools, Homo economicus served well enough: given choice, people will act in their own interest, and by so doing make the system work better for everyone. This is a useful, but flawed, shortcut to understanding human behaviour.
The most influential thinkers of the earlier Enlightenment were consumed by the question of how to balance reason with the primitive and softer elements in our nature. Adam Smith’s greatest influence, David Hume, was adamant that reason ‘ought only to be the slave of the passions’. For Hume, emotions drove people to apply reason, to satisfy basic desires for food or sex, or more complex behaviours such as curiosity and ambition.
Smith, too, offered a sophisticated analysis of our instincts for fairness and social sympathy in his first book, The Theory of Moral Sentiments (1759). Despite being the Zeus of market rationality, Smith’s arguments for these forces to balance self-interest were lost in the laissez-faire hubris of the recent decades leading up to the financial crisis.