Chapter two is titled Attention. It’s about how what we attend to tends to shape our sense of reality. This is a story of the functional speciality of the hemispheres and their mediating components. Each hemisphere has its own protocols and modus operandi, each with distinct task specialisation. Important to note coming in is that about thirty per cent of all neuronal activity is inhibitory in nature. In fact, the frontal lobe is what inhibits the reflexive animal-reptilian responses allowing for some—I mean, let’s be honest here—human civil capacity. These mediating elements are designed—idiomatically, not literally—to orchestrate hemispheric activities so that each side can do what it’s best suited for.
Both hemispheres attend to their environments, but they have different foci. One way to distinguish which hemisphere is focused on what, McGilchrist regards research oriented toward people with damage to one or the other part, whether by a stroke or accident. In some cases, this separation is accomplished clinically. There is a difference between right- and left-handedness, but I am not going to elaborate here.
Persons with left hemisphere damage noted difficulty writing and spelling whilst right hemisphere damaged people experienced a loss of empathy as well as a range of cognitive and emotional impairments.
In general, the right hemisphere attends to the broader environment with a trade-off on specificity whilst the left hemisphere is laser-focused at the expense of the wider perspective and ability to maintain attention. Evidently, and I quote, “the left hemisphere has a tendency to ‘space out’ for seconds (sometimes 15 or more) at a time”. McGilchrist cites the invisible gorilla study where viewers are asked to watch a video clip of two teams of basketball players dribbling and passing a ball to count the number of times one team passes the ball. As this is happening, a person dressed in a gorilla costume walks into frame and makes gestures to bring attention to itself and then walks out of frame.
Focusing on the ball passing is a left-brain function that predominates right-brain activity. As it is laser-focused on the task at hand, it is oblivious to the gorilla in the midst. When re-viewing the clip without the focus activity, the gorilla is quite obviously present. He cites another substitution study that again illustrates what happens when the right brain does not have an audience.
Again, whilst “the right hemisphere is sensitive to the whole picture in space and time, background and periphery, the left hemisphere is focussed on what is central in the field of vision and lies in the foreground.” This becomes evident with hemispheric damage. When the left hemisphere is damaged, people can still perceive the full view-frame because the right hemisphere remains intact, but when the right hemisphere is damaged, less than half of the world remains. In the book, some examples follow.
The left hemisphere suffers from a stickiness problem. Without a participating right hemisphere, a person can have their attention fixated on some objects in the environment. And he points out that this is not a problem with visual perception, because tests demonstrate that subjects can be made to fixate on imaginary objects in a dark room. In schizophrenics, this fixation always occurred on the right side of the field of vision. This fixation ties into staring, which he describes as “a special kind of vision, in itself predatory: left hemisphere attention gets locked onto its target.” I’ll guess that many of us have been fixated on some activity and an unexpected interloper startles us when they become apparent. He mentions the discredited Sapir-Whorf hypothesis in passing. I won’t bother.
McGilchrist foreshadows chapter four a bit by informing the reader that the left hemisphere is grasping and apprehending whilst the right hemisphere excels at comprehending. More on this in future segments.
Another feature of the left hemisphere is that it not only ignores the majority of the environment it finds itself in, but it is also a master of denial. For example, a person with right-hemispheric damage was paralysed on the left side of his body, yet he was not only unaware of the paralysis. He denied that he was paralysed.
In a second case, another person with right-hemisphere damage and left-side paralysis, when asked to perform tasks would comply with the requests directed toward the right side of the body but ignore or claim not to understand the directions when directed toward the left side.
What this represents is that the left hemisphere had established a map of the body that was unable to be updated because of the damage to the right hemisphere that would have provided an update. One might consider this in the manner of an old SAT-NAV when map updates needed to be manually applied. If you happen to be travelling in a new development on an obsolete map, the map will not correspond to the terrain.
As mentioned previously, the right hemisphere can be thought to present whilst the left hemisphere can be thought to re-present, having codified and archived the contents for later retrieval. The book has more types of examples including people experiencing reality through a set of freeze-frames and time elapses, but the takeaway is that the hemispheres also differ in how they interpret space, time, and motion. In fact, the right hemisphere is instrumental in perceiving three-dimensional space.
I won’t exhaust the many remaining examples in the book, though I may reference some in summary when I share my reaction and perspective. The final topic I’ll mention is that human infants are right-hemisphere dominant. They are practically all about gathering inputs without being concerned with how they map the terrain for later retrieval. They simply experience the world without the analysis and judgment the left brain later brings to bear.
At the end of the chapter, McGilchrist provides a summary. The right hemisphere is always vigilant to what might be out there. For the left hemisphere, if it hasn’t been brought to attention, it doesn’t exist. Consider the invisible gorilla. The left hemisphere’s attention is sharply restricted in space and time. It favours precision over accuracy and at the expense of depth. It is not concerned with the “expansive, always moving, always changing, endlessly interconnected nature of reality.” The left is all about atomisation and stasis.
Unfortunately, despite all these limitations, the left still thinks it’s right. Revisiting the SAT-NAV scenario, the left brain is akin to a person staring at the screen that declares the destination has been reached. The right brain looks out the window and informs that they are decidedly not in the right place. Does one trust the instrumentation or the environment?
One undercurrent I feel is that McGilchrist wants to play the left and right hemispheres against each other to assess which is more veridical. This is where I think we differ, but the jury is still out. In his case, he wants to compare the way that each hemisphere maps to our experience of the real world. In his view, and I don’t think I am putting words into his mouth, our experience is the world because we experience it as it appears to us. In my view, experiences are simply a representative map as limited by our sense-perceptions and cognitive abilities. So, when he assesses the right hemisphere as a better reflection of reality, I say it just better captures the map.
For him, it’s either left or right. But for me, it’s right, left, or none of the above. I believe our disagreement is that I subscribe to a fitness before truth paradigm whilst McGilchrist doesn’t. I feel that fitness is the evolutionary litmus, and evolution doesn’t care about truth. In fact, assessing truth comes at the expense of energy and attention, the subject of this topic. The reason the case studies cited in this chapter are interesting is not that they illustrate some truth deficit that would render them easy prey in a Darwinian world, it’s because their perception leaves them with a fitness penalty. There is no reason to invoke some spectre of truth.
This was an interesting chapter with over a dozen clinical anecdotes. It does well to articulate the differences in hemisphere function and lends credence to left and right brain asymmetry. I feel it’s worth cracking on to the next chapter, Perception.
Before I bring this commentary to a close, I want to make an orthogonal comment. McGilchrist mentioned case studies where people reported freeze-framing. It is understood that certain birds have a faster frame rate than humans, so if they were viewing a movie running at 60 frames per second, they would not see the same continuous motion picture as a typical person; rather, they would perceive it as how we might perceive a slide show or a slow flip book. Of course, this is unrelated to the brain conversation, but the topic reminded me of the difference. For anyone who feels they need to educate me about the fact that the ocular systems don’t operate in frames per second, allow me instead to direct you to the domain of metaphor and analogy.
What are your thoughts on the split function of brain hemispheres? If you’ve read the book or at least this chapter, what was your favourite story? Did I omit your favourite? Leave comments below or on the blog.