The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World

by Iain McGilchrist

Second, it so happens that the right hemisphere is the source of our sense of time, as something lived through, as having duration (what Bergson called durée, in contrast with temps).44 This is precisely what we would expect if the right hemisphere deals with the sustained continuity of real experience – where everything that happens, happens in the flow of time – and the left hemisphere with a comparatively abstract realm, snapshots taken out of the flow, beyond the real-world context of actual, specific, existing beings that are subject to change.

Right hemisphere damage leads, then, to impairment in the perception of temporal flow. And, importantly, the right hemisphere has a longer working memory, so that it is better able to maintain in awareness what is attended to over time. Take that away and our experienced reality may fragment.

‘the left hemisphere stores spatial information as discrete, salient locations and that the right hemisphere represents space continuously, contributing to route computation and flexible spatial navigation’.

Including about the truth: there is a strong tendency to disown problems, fail to take responsibility, and to maintain to the last that it is ‘nothing to do with me, guv’. The right hemisphere-damaged, left hemisphere-reliant, patient is always in the right.

If you don’t know how to explain something, why not just make it all up? Welcome to another important feature of the left hemisphere’s world: confabulation.

Remember, when it comes to the left hemisphere, it’s always someone else’s fault.)

But, once again, joining up the dots to see the whole is a quintessential function of the right hemisphere, not the left. Some such right hemisphere deficit, resulting in fragmentation of the sense of self, may be involved in dissociative states and multiple personality syndromes.

The left hemisphere begins with parts, and any idea of the whole is built up from those parts. By contrast, the right hemisphere begins with the whole and any ‘parts’ are just aspects of the whole that have been artificially decontextualised.

This phenomenon demonstrates what is known as the ‘hierarchy of attention’, which means that we see things whole with the right hemisphere first, before homing in on details with the sharply, but narrowly, focussed gaze of the left hemisphere.

One difference is that the left hemisphere sees the body as an object ‘out there’ in space alongside other objects, while the right hemisphere feels the body to be what we experience as a whole ‘from the inside’.

One way of putting it is that the left hemisphere can provide some sorts of knowledge about the world, as it would be scrutinised from a certain theoretical point of view effectively outside the realms of space and time (as on a map); whereas the right hemisphere provides us with the knowledge of the world in space and time (as experienced).

‘We live in two worlds, the world of sight and the world of thought’, wrote Friedrich Max Müller, one of the most celebrated philologists of the nineteenth century, ‘and, strange as it may sound, nothing that we think, nothing that we name, nothing that we find in our dictionary, can ever be seen or heard, or perceived.’

Perception is the act whereby we reach out from our cage of mental constructs to taste, smell, touch, hear and see the living world.

Because in us something new happens: to be precise, it starts happening in the great apes. It is the ability to use symbols – tokens or representations for things. And in humans it is advanced out of all recognition by language, which gives us a virtually inexhaustible way of mapping the world, to which perception is, to all intents and purposes, irrelevant – and from which it may even prove a distraction.

To be good at perceiving is to be good at integrating information.

Experience is a sensorimotor – and intuitive – participation, a fusion of one’s own awareness with awareness in the world.

Perception is not passive reception, but participation. (As is all consciousness, but that is a story for later.)

In other words, if you want an accurate assessment rather than a quick one, the right hemisphere is to be preferred. In fact there is evidence that the left hemisphere gets less reliable as you give it more time to respond – perhaps because it is then prone to rely on conscious processing, which immediately limits possibilities.

One important element in perception is the ability to make sense of a stimulus using contextual information. This requires a swift capacity to synthesise bottom-up, local, information, with top-down, holistic, information, a process that depends principally on the right hemisphere.

While the left hemisphere underwrites local attention, the right hemisphere underwrites global attention, as we saw in the previous chapter – and the ability to switch between them.

Thus the right hemisphere makes it possible to switch interpretations, whether between interpretations of what both eyes see, as in the stairs (perceptual rivalry), or between what each eye sees (binocular rivalry); and right hemisphere damage makes it hard to switch, in line with what I call the stickiness of the left hemisphere.

Not to see the whole is to see things out of context.

The right hemisphere, especially the right inferior parietal lobe, is of vital importance for our awareness of self, beginning with the physical self, but going beyond that.

At the risk of over-simplification, the objectified self, and the self as an expression of will, is generally more dependent on the left hemisphere; whereas the self as empathically inseparable from the world in which it stands in relation to others, and the continuous sense of self, enduring over time, are more dependent on the right hemisphere.

The right hemisphere seems embedded in the world, whereas the left hemisphere is intrinsically abstracted from the world.

Almost all extraordinary distortions of reality follow from right hemisphere damage.

It seems that when the right hemisphere’s guidance is lacking, we are much more likely to make both over-credulous, and over-sceptical, judgments on reality.

In every sensory modality the right hemisphere appears to have an advantage over the left when it comes to primary perception.

Distinguishing delusions (distorted reality judgments) from hallucinations (distorted perceptions) is to some degree arbitrary, since misperceptions can give rise to misbeliefs, and misbeliefs give rise to misperceptions.

‘Delusions may … arise when the left hemisphere’s tendency to explain goes awry; indeed, delusional disorders are characterized by excessive inference making and the tendency to prematurely jump to conclusions.’

This is thought to be because of a need for closure – a tendency to prefer an answer, irrespective of its plausibility, to ambiguity and uncertainty.9 This is a tendency that is also reflected in the culture of modernity: it encourages us all to rush for closure.

What happens is not that reality is primarily shaped by the left hemisphere, albeit in delinquent fashion, and that this is then knocked into a realistic shape by the thought police of the right hemisphere, but that reality is primarily shaped by the right hemisphere. So when the right hemisphere is malfunctioning, the left hemisphere is relatively at a loss.

In other words, with the left hemisphere knocked out they were fully aware of the contralateral deficit; with the right hemisphere knocked out, they were completely oblivious of it.

The left temporal lobe is involved in putting a name to a face; but by contrast the recognition of the face as a face, as familiar, and as a particular person, as well as the understanding of its expression – all that is dependent on the right hemisphere.

This is in keeping with other evidence that all forms of delusional self-misidentification are dependent on right hemisphere deficits.

I mentioned that the right hemisphere supports the body schema. One of the most fascinating aspects of this is that an intact body schema is innate, even in those whose body from birth was abnormal.

Insight is very largely right hemisphere-dependent.

In understanding one’s role in bringing about a certain outcome, depressives are more ‘in touch’ with reality even than normal subjects: depressive subjects were remarkably accurate, whereas normal subjects overestimated their role in bringing about wished for results, and underestimated their role in bringing about unwished for results.

This fits with the observation that, across a range of functions, while things are running routinely, the left hemisphere deals with them; but when they are exceptional – ‘unique’ or ‘complex’ – the right hemisphere is brought in to deal with the situation.

The left hemisphere appears to detest uncertainty; it creates explanations and fills in gaps of information in order to build a cohesive story and extinguish doubt.

Of course, sometimes we are guided by our own explicit self-ascriptions and goals, and at others by our implicit motives, so both are relevant to understanding how we behave.

According to David McClelland, who developed the influential Achievement Motivation Theory, implicit motives are a right-hemispheric phenomenon and explicit motives are left-hemispheric.

there is a significant difference between what we say we believe (which is what rating scales assess) and what we actually believe when push comes to shove.

That claim seems a little ambitious to me, but whether that is so or not, ‘magical ideation’ is by definition not in itself delusional, though it may be on a continuum with delusion. It simply suggests a greater willingness to consider connexions, some of which are no doubt non-existent, but some of which may simply not be recognised in the current Western standard model.

And that which is ultimately without foundation may hardly be disadvantageous, simply being an exaggeration of a cautionary principle that makes sense in terms of survival: it’s better to see tigers in leaf patterns where there aren’t any, than to fail to spot tigers in leaf patterns where there are.

Additionally male brains exhibit greater intrahemispheric, and females greater interhemispheric, structural connectivity.203 What these findings together suggest is that the hemispheres are more specialised in the male than the female brain.

According to Belinda Pletzer, one of the leading researchers in the area, many lines of evidence show that males process more globally, females more locally: there is ‘a stronger focus on the global level (holistic processing) in men and a stronger focus on the local level (decomposed processing) in women’.

In women, global choices are slower than local choices, whereas in men they are faster. Testosterone is positively related, and progesterone negatively related, to the use of global strategies.

And the two most reliable sex differences, neuropsychologically speaking, are that females in general have greater verbal facility and males better visuo-spatial skills, and that this is related to testosterone.229 Females do better academically where material is familiar and prepared.230 Finally, in rats, too, it has been found that the right cortex is thicker than the left in males, but the left thicker than the right in females.

The madman is not the man who has lost his reason. The madman is the man who has lost everything except his reason.