The Divided Brain and its Implications for Attention and Creativity

The Debunking of a Myth

To understand the relationship between attention and advertising creativity I draw in my two books (Lemon and Look out, IPA, 2019 and 2021) on the work of a psychiatrist, neuroscience researcher and philosopher, Dr Iain McGilchrist. McGilchrist has devoted himself to a study of the two hemispheres of the brain, and the different ways in which they pay attention to the world; he is perhaps the world’s leading expert on brain lateralisation.

The notion that the two hemispheres might do different things was first posited in the 1960s. Patients who had undergone commissurotomy (a procedure to divide the two brains to prevent the spread of an epileptic seizure across the whole brain), led to a view that the left and right hemisphere did different things, as if the brain were a machine with different functions. You have probably seen the sort of diagram of the brain that emerged from this pop psychology narrative – depicting the left hemisphere ‘doing reason’ and the right ‘doing emotion,’ or suggesting the left hemisphere is responsible for ‘logic and analysis’ while the right hemisphere contents itself with ‘creative thinking and art.’ This myth, which took hold in popular culture, has now rightly been dismissed, but for many years it stigmatised the serious scientific study of brain lateralisation. Indeed, McGilchrist himself was discouraged from entering the field for this very reason. But this does not mean that the whole field has been debunked, just that our understanding of it has moved on.

The Asymmetrical Brain

McGilchrist took up medicine following his undergraduate degree and trained as a psychiatrist. He sat by chance in a lecture given by John Cutting, where Cutting observed the changes that occur following right hemisphere strokes. The lecture described how right hemisphere strokes can result in a loss of the sense of the unique, a loss of context, a misunderstanding of the implicit, and a sense for the subject that everything has become disembodied. As McGilchrist pursued his research, he came to the realization that the right hemisphere brings a radically different kind of attention to bear on the world from the left – one that is broad, open, and vigilant – and quite different from the narrow and fixed attention of the left hemisphere.

McGilchrist went on to become a practising psychiatrist and a clinical director at the Bethlem, Royal and Maudsley Hospital, London, and a research fellow in neuroimaging at Johns Hopkins Hospital, Baltimore. Drawing on studies from patients with lateralised brain lesions (trauma, strokes, tumours), hemisphere inactivation experiments in normal subjects, experiments on split-brain subjects, EEG, fMRI and neuroimaging studies, McGilchrist arrives at a deeply nuanced and explanatory picture of the two hemispheres, how they relate to each other and to the world. And he stresses the importance of not relying too heavily on any one of these approaches when it comes to isolating localization – particularly scanning studies. As others have pointed out (Rorden & Karnarth, 2004), techniques such as fMRI can be less reliable than the lesion method because a task that is processed in one hemisphere will produce bilateral activation in the other. The lesion method is therefore an important method in understanding hemisphere lateralisation because it measures brain disruption. It is important to view the results of these different types of study together, which is what McGilchrist sets out to do. His books are as meticulously referenced as they are philosophically profound; The Matter with Things contains a bibliography that spans 182 pages.

In this, his latest book, he explains that there is nothing about the hemispheres that is symmetrical. Differences emerge very early in the foetal brain – as early as the 11th week of gestation. And in a fully developed brain, the two hemispheres differ in weight and size, shape, the number of neurons, structure at the cellular level, neuronal size, branching, the ratios of grey to white matter, response to hormones and the extent to which the hemispheres rely on different neurotransmitters – even the convolutions of the brain’s cortical surface. The two hemispheres are, then, anatomically different, as a simple matter of fact.

Why might this be, and indeed, why do we have two hemispheres at all?

Reframing the Debate

McGilchrist helpfully reframes the debate; it isn’t that the two hemispheres do different things, as the pop psychology narrative once suggested, it is more that the two hemispheres do things differently, they have different modes of attention. The right hemisphere deals with the global picture – including the periphery and the background – whereas the left hemisphere deals with the local, what is right in front of it, in the foreground. These two types of attention answer a fundamental problem – how we can eat, while ensuring that we ourselves are not eaten. The left hemisphere helps us to grasp and feed, while the right hemisphere with its always-on context-aware global attention ensures we do not become someone else’s prey. You might describe these as broad-beam (right) and narrow-beam (left) attention. And we tend to understand the broad picture first.

Right Hemisphere Impairment

From this, everything else follows, and McGilchrist describes how right hemisphere impairment results in disorders of time, space, motion, and emotion, can lead to confabulation (the making-up of plausible stories if it doesn’t know the answer), paranoia and a devitalised view of the world. Right hemisphere impairment also has a bearing on our ability to grasp metaphor and understand narrative. Similar symptoms present themselves in schizophrenia; the condition has much in common with hyperfunction of the left hemisphere: patients experience a breakdown in global attention and become hyperconscious – conscious of consciousness (for more on this and its relationship with creativity, see Madness and Modernism, 2017, by the esteemed psychiatrist Professor Louis Sass). McGilchrist explains how the right hemisphere grounds us in the world and the people in it; it helps us to convey and understand emotion in the human face, voice and body, helps us to understand depth and time, metaphor, music and even humour. His study of the left hemisphere reveals that it tends to abstract and flatten things, better to control and manipulate them, to break things down into smaller parts and to categorise things (‘it’s one of those…’). It also has a different emotional timbre and a sense of superiority that can make it rather dogmatic. The two hemispheres therefore bring into being a different world for us and we clearly need them both.

Nikolaenko, 1997. Each row is drawn by a different person while the left or right brain is suppressed; each column shows how the flower is drawn when both hemispheres are active, or when one or other hemisphere only is active. A flower drawn by the right hemisphere is shown as a whole and in three dimensions; when drawn by the left hemisphere, it is flattened and abstracted, and reduced to a sign or symbol.

The Application of Hemisphere Theory: Attention and Creativity

In my books, I have drawn on McGilchrist’s hemisphere theory to understand the effectiveness of advertising. At System1 we test advertising for emotional response; we also provide guidance for advertisers wishing to make work that connects better with audiences for better business outcomes. We have found that advertising that might be said to speak to the ‘broad-beam attention’ of the right hemisphere, with its ability to understand social context and the living, is much more likely both to capture attention and to elicit an emotional response. This means the kind of advertising that features characters, with human expression, movement and connection, a scene unfolding in lived time, the emergence of something unusual from the scene. Advertising that features the abstraction of the left hemisphere, tends to push audiences away. This is not a one-off finding, but one we have replicated across many datasets comprising very large numbers of ads, and across different media channels.

Correlation between presence of feature and emotional response (System1) and creative attention score (TVision), from Look out (IPA, 2019).

When we turn to business outcomes, this kind of advertising for ‘broad-beam attention’ tends to be more likely to establish brand fame and trust. It is also much better able to achieve very large and lasting business effects, such as share gain, profit gain and sales gain, than advertising that might be said to speak to the ‘narrow-beam attention’ of the left hemisphere, where things are shown close-up, abstracted, and devitalised. If this second kind of advertising has a strength, it is to grasp at a sale; it is slightly better at generating direct effects, that’s to say to nudge prospects in the buying window now towards a website, an app, or a purchase. And it is towards this kind of ‘left-brain’ advertising with its short-sharp cuts, its abstraction, its rhythmic soundtrack, that we have gradually drifted over the last 15 years or so, in our highly targeted digital world.

So, for advertisers seeking to create the kind of work, that builds fame and trust, and helps to establish broad and lasting effects, understanding broad- and narrow-beam attention is very important. The implications of McGilchrist’s hemisphere theory don’t stop here, however. His extraordinary work has lessons for us wherever we look.

Orlando Wood is Chief Innovation Officer at System1, author of Lemon and Look out (Institute of Practitioners in Advertising, 2019 and 2021), and Honorary Fellow of The Institute of Practitioners in Advertising. 

About Iain McGilchrist

Dr. Iain McGilchrist is author of The Master and His Emissary and The Matter with Things. He is a fellow of All Souls College, Oxford, and associate fellow of Green Templeton College, Oxford, a fellow of the Royal College of Psychiatrists. He is a former consultant psychiatrist and a clinical director at the Bethlem, Royal and Maudsley Hospital, London. He has also been a research fellow in neuroimaging at Johns Hopkins Hospital, Baltimore, and a fellow of the Institute of Advanced Studies in Stellenbosch. His work is of interest to some of the most distinguished figures working in neuroscience today.

If you are looking for a short and accessible overview of McGilchrist’s work, try this animation by the Royal Society of Arts.

If you would like to read more about McGilchrist’s work, and what other leaders in the field have said about it, you might be interested in his channel.