“Asymmetry and the Brain” in The Master and his Emissary by Iain McGilchrist (part I)

In this first chapter, McGilchrist begins laying the neurological foundation for his argument that the bihemispheric structure of the human brain results in two different ways of being in the world. The most relevant material for my purposes is McGilchrist’s discussion of how various animals with a bihemispheric neurological structure provide a phylogenic precedent for the differing ways of attending to the world that is present in humans. Additionally, the link that McGilchrist sketches between the relation of needs, values, ways of attending, and kinds of things is crucial for situating science in relation to commonsense properly.

Attention in animals

McGilchrist frames the different ways that animals and humans attend to the world in terms of sorting out competing needs. Each hemisphere is suited to a different kind of attending, or a different manner of being in the world. This is true for both animals and humans. Apparently, some bihemispheric animals and birds employ just one eye to perform specific tasks that require a distinct kind of attending to the world.

There is a need to focus attention narrowly and with precision, as a bird, for example, needs to focus on a grain of corn that it must eat, in order to pick it out from, say, the pieces of grit on which it lies. At the same time there is a need for open attention, as wide as possible, to guard against a possible predator. That requires some doing. It’s like a particularly bad case of trying to rub your tummy and pat your head at the same time—only worse, because it’s an impossibility. Not only are these two different exercises that need to be carried on simultaneously, they are two quite different kinds of exercise, requiring not just that attention should be divided, but that it should be of two distinct types at once. (1)

This reveals important information about the bihemispheric structure of the brain because each eye is controlled by its directionally opposite hemisphere: the right eye is controlled by the left hemisphere and the left eye is controlled by the right hemisphere. Therefore, functions and tasks that make either the left or right eye dominant confirm different functions for the hemispheres.

These basic incompatibilities suggest the need to keep parts of the brain distinct, in case they interfere with one another. There are already hints here as to why the brain may need to segregate its workings into two hemispheres. If you are a bird, in fact, you solve the conundrum of how to eat and stay alive by employing different strategies with either eye: the right eye (left hemisphere) for getting and feeding, the left eye (right hemisphere) for vigilant awareness of the environment. More generally, chicks prioritize local information with the right eye (left hemisphere), and global information with the left eye (right hemisphere). […] Many types of bird show more alarm behavior when viewing a predator with the left eye (right hemisphere), are better at detecting predators with the left eye, and will choose to examine predators with their left eye, to the extent that if they have detected a predator with their right eye, they will actually turn their head so as to examine it further with the left. Hand-raised ravens will even follow the direction of gaze of a human experimenter looking upwards, using their left eye. For many animals there are biases at the population level towards, again, watching out for predators with the left eye (right hemisphere). In marmosets, individuals animals with more strongly lateralized brains are better able, because of hemisphere specialization, to forage and remain aware of predators. There are shorter reaction times in cats that have a lateralized paw preference. Lateralized chimps are more efficient at fishing for termites than unlateralized chimps. Even individual human brains that are, for one reason or another, less ‘lateralized’ than the norm appear to show global deficits. In a word, lateralization brings evolutionary advantages, particularly in carrying out dual-attention tasks. (2)

McGilchrist continues to pile on the data regarding the animal kingdom:

In predatory birds and animals, it is the left hemisphere that latches on, through the right eye and the right foot, to the prey. It is certainly true of familiar prey: in toads, a novel or unusual choice of prey may activate the right hemisphere, until it becomes familiar as an object of prey, when it once again activates the left. In general, toads attend to their prey with the left hemisphere, but interact with their fellow toads using the right hemisphere. (3)

And finally:

Perhaps it is just a nice coincidence that the wry-billed plover, a native of New Zealand, which uses its beak to search for food under stones, has a bill which is curved to the right, so that it will be of most use to its manipulative left hemisphere. No doubt there may be counterexamples. But there does seem to be a consistent thread running all the way through. Speech is in the left hemisphere in humans: what then about the instrumental vocalizations of other species? They arise also in the left hemisphere, in such diverse creatures as frogs, passerine birds, mice, rats, gerbils, and marmosets. Similarly there is a strong right eye (left hemisphere) bias for tool manufacture in crows, even where using the right eye makes the task more difficult. This has, as we will see when we come to consider the human situation, some important resonances for the nature of our own world. But when it comes to mediating new experience and information it is already the right hemisphere, in animals as in humans, not the left, that is of crucial importance. (4)

Attention in humans

So, who cares? What is the significance of the animal research? It is this: bihemispheric structure suggests diverse applications of task-specific modes of focus or attention. Understanding the various kinds of attending that arise from the bihemispheric structure of animal neurology sheds light on the same phenomena in humans. However, the diverse modes of attending are more acute in humans than any other animal, perhaps because of the greater expansion of humans’ frontal lobes. This ability of humans to stand apart from our immediate, bodily experience probably contributed to our early designation as a “rational” animal.

Nonetheless, pivoting with sophistication is not easy and McGilchrist argues that the need to do so may have contributed to the bihemispheric neurological structure in both animals and humans. (Interestingly, Bernard Lonergan argues that pivoting between ways of attending to the world explicitly and with sophistication is required for doing good epistemology and that failing to pivot well leads to numerous philosophical errors. This is a major theme of my dissertation and I hope to spell out the relation between McGilchrist’s argument and Longeran’s in due course.) McGilchrist discusses pivoting between what he calls ‘terrain’ and ‘territory’:

Clearly we have to inhabit the world of immediate bodily experience, the actual terrain in which we live, and where our engagement with the world takes place alongside our fellow human beings, and we need to inhabit it fully. Yet at the same time we need to rise above the landscape in which we move, so that we can see what one might call the territory. To understand the landscape we need both to go out into the felt, lived world of experience as far as possible, along what one might think of as the horizontal axis, but also to rise above it, on the vertical axis. To live headlong, at ground level, without being able to pause (stand outside the immediate push of time) and rise (in space) is to be like an animal; yet to float off up into the air is not to live at all—just to be a detached observing eye. One needs to bring what one has learned from one’s ascent back into the world where life is going on, and incorporate it in such a way that it enriches experience and enables more of whatever it is that ‘discloses itself’ to us (in Heidegger’s phrase) to do just that. But it is still only on the ground that it will do so, not up in the air. (5)

But, as was mentioned, pivoting between these two ways of attending could be problematic if we didn’t possess the adequate neurological infrastructure to pull it off. Fortunately, we do. Generally speaking, the right hemisphere supports a wide, immediate, and context-rich kind of attending, while the left hemisphere supports the narrow, focused attending typical of analysis.

In humans, just as in animals and birds, it turns out that each hemisphere attends to the world in a different way—and the ways are consistent. The right hemisphere underwrites breadth and flexibility of attention, where the left hemisphere brings to bear focused attention. This has the related consequence that the right hemisphere sees things whole, and in their context, where the left hemisphere sees things abstracted from context, and broken into parts, from which it then reconstructs a ‘whole’: something very different. And it also turns out that the capacities that help us, as humans, from bonds with others—empathy, emotional understanding, and so on—which improves a quite different kind of attention paid to the world, are largely right-hemisphere functions. (6)

The nature of attention

But what are we talking about when we talk about attending? For McGilchrist, attending is the manner in which we treat a need, or an object, in our world. He argues that attention is not merely another cognitive function, but ontological prior to all other cognitive functions since it is present in each of them. Further, the different exigencies we encounter in life cause humans to pay attention to the world in different ways, which in turn brings different kinds of things into focus.

 The kind of attention we bring to bear on the world changes the nature of the world we attend to, the very nature of the world in which those ‘functions’ would be carried out, and in which those ‘things’ would exist. Attention changes what kind of a thing comes into being for us; in a way that changes the world. If you are my friend, the way in which I attend to you will be different from the way in which I would attend to you if you were my employer, my patient, the suspect in a crime I am investigating, my lover, my aunt, a body waiting to be dissected. In all these circumstances, except the last, you will also have a quite different experience not just of me, but of yourself: you would feel changed if I changed the type of my attention. And yet nothing objectively has changed.

So, it is, not just with the human world, but with everything with which we come into contact. A mountain that is a landmark to a navigator, a source of wealth to a prospector, a many-textured form to the painter, or to another the dwelling place of the gods, is changed by the attention given to it. There is no ‘real’ mountain which can be distinguished from these, no one way of thinking which reveals the true mountain. (7)

(I simply note here how similar this language about attending sounds to John Dewey’s discussion of experience in Experience and Nature and Art as Experience.)

McGilchrist does not deny that humans can get the ultimate truth of things, but he is suggesting that there is no “view from nowhere” where human perception is free from a specifically focused mode of attending to the world. There is no viewpoint, or form of human knowledge, that was not produced by an attending human brain. Moreover, each way in which we attend to the world is propped up and reinforced by a particular set of values relevant to present circumstances or goals, which means each way of attending to the world is heavily value-laden. And this includes both commonsense and science.

Proponents of scientism often assume that the scientific method, or scientific institutions, function as error filters which reduce, or eliminate, bad forms of human thinking, thereby ensuring that the products of science are free from the messiness of human brains. In other words, it is assumed that science achieves the “view from nowhere” that McGilchrist denies. McGilchrist, however, does not deny that scientific methodology successfully filters out bad forms of thinking, but he does insist that such filters do not prevent scientific attending from being value-laden. McGilchrist does not discuss here what these values are, so neither will I, but the kind of attending that is called scientific, as well as the fact that we recognize it as scientific attending, will be addressed in due course. Part of what I intend to do in my dissertation is describe the ways in which commonsense and scientific discourse constitute different realms of meaning because they involve different ways of attending to our world and our experience. One can see, then, why McGilchrist’s work is of interest.

I end these notes on this chapter with the following passage from McGilchrist:

Experience is forever in motion, ramifying and unpredictable. In order for us to know anything at all, that thing must have enduring properties. If all things flow, and one can never step into the same river twice—Heraclitus’s phrase is, I believe, a brilliant evocation of the core reality of the right hemisphere’s world—one will always be taken unawares by experience, since nothing being ever repeated, nothing can ever be known. We have to find a way of fixing it as it flies, stepping back from the immediacy of experience, stepping outside the flow. Hence the brain has to attend to the world in two completely different ways, and in so doing to bring two different worlds into being. In the one, we experience—the live, complex, embodied, world of individual, always unique beings, forever in flux, a net of interdependencies, forming and reforming wholes, a world with which we are deeply connected. In the other we ‘experience’ our experience in a special way: a ‘re-presenting’ version of it, containing now static, separable, bounded, but essentially fragmented entities, grouped into classes, on which predictions can be based. This kind of attention isolates, fixes and makes each thing explicit by bringing it under the spotlight of attention. In doing so it renders things inert, mechanical, lifeless. But it also enables us for the first time to know, and consequently to learn to make things. This gives us power.

These two aspects of the world are not symmetrically opposed. They are not equivalent, for example, to the ‘subjective’ and ‘objective’ points of view, concepts which are themselves a product of, and already reflect, one particular way of being in the world—which in fact, importantly, already reflect a ‘view’ of the world. The distinction I am trying to make is between, on the one hand, the way in which we experience the world pre-reflectively, before we have had a chance to ‘view’ it at all, or divide it up into bits—a world in which what later has come to be thought of as subjective and objective are held in a suspension which embraces each potential ‘pole’, and their togetherness, together; and, on the other hand, the world we are more used to thinking of, in which subjective and objective appear as separate poles. At its simplest, a world where there is ‘betweenness’, and one where there is not. These are not different ways of thinking about the world: they are different ways of being in the world. And their difference is not symmetrical, but fundamentally asymmetrical. (8)

Notes:

(1) McGilchrist, p. 25.

(2) ibid, p. 26.

(3) ibid, p. 26.

(4) ibid, p. 27.

(5) ibid, p. 21-2.

(6)  ibid, p. 27-8.

(7) ibid, p. 28.

(8) ibid, p. 31.