Image credit: *Neuroanatomy: An Atlas of Structures, Sections, and Systems* by Duane E. Haines, page 20.

On average I read eight to ten books a month, fiction and non-fiction, for a couple hours at the end of my day in bed. Since July, after landing the book deal with W.W. Norton, I’ve also been reading one book—The Master and His Emissary: The Divided Brain and the Making of the Western World by Ian McGilchrist, MD, a British psychiatrist and philosopher—for a couple hours most mornings at the desk after a few cups of coffee.

How many pages do I read in two hours? About ten. The material is so dense, I have to take notes to stay focused. (More on that in a few paragraphs.) I haven’t worked this hard since medical school!

The book is about the differences between the right and left cerebral hemispheres. The right hemisphere interfaces directly with reality outside us—the world and others—and sends those rich, overwhelming, ambiguous impressions to the left hemisphere to “unpack” with language, analysis, and logic.

The right hemisphere sources our experience of aliveness—and meaningful connection with the world and others—through bodily and sensory experience. It concerns itself with the relationships between ourselves and others, in a caring way, always in context. It does not have language and thinks in images and sensation. It understands what is happening all at once, as an a-ha moment.

The left hemisphere, by contrast, has no direct contact with the outside world. Like an owl closing in on a mouse with claws outstretched, the left hemisphere focuses in on what it recognizes within the novelty, ambiguity and complexity of what the right hemisphere sends it. The speech centers are located in the left hemisphere only. It uses language and sequential logic to break down what the right sends into abstract, defined, fixed parts. It builds its version of reality from those parts, as if constructing a machine.

Thus, the two sides have very different points of view, agendas and realities. If the corpus callosum, the neural bridge connecting the two sides, is severed, either hemisphere alone can enable a person to live successfully in the world. But the life that person leads will be very different depending on which hemisphere is in charge.

You’d think because the speech centers are located in the left hemisphere that the left would run all our communications. But only the dictionary and syntax we use are located there. 80% of human communication occurs without words!

Non-verbal communication and music are mediated by the right hemisphere. Before we learn to speak, we communicate with our mother and others by touch, eye contact and all the vocalizations that we use to sing: pitch, tone, phrasing, rhythm, volume and more. Think of the chef’s kiss gesture—it says so much more than words alone. That’s because the gesture delivers its meaning by engaging the whole self: mouth making the kiss sound, facial expression, hand, the entire body, attitude—all the domain of the right hemisphere.

Here's a corollary fascinoma. Only birds can vocalize at our level of complexity! Both humans and birds have the necessary wiring (nerves to tongue and vocal cords) and musculature (respiratory muscles and lung capacity) that make that richness possible. However, we sing for different reasons. Birds sing adversarially, when competing for territory (mediated by the left hemisphere). We sing to connect with each other in a shared, group experience, such as choir singing (mediated by the right hemisphere).

Observations On the Way I Found Myself Taking Notes

This insanely brilliant book—526 pages in absurdly small font—contains way too much complex material for my working memory to hold reliably. So, I’ve been taking notes by hand in a cheap comp book, the kind with mottled black and white covers and college ruled lines. (I’m into the third comp book and halfway through the book. Yay me!)

I’ve found myself taking notes only on the right sided page of the comp book, not both sides. When an idea comes to me, or a question, or a relevant case from my practice, I’ve jotted that on the left sided page, which—how convenient— is blank. Notes on the right, musings on the left. I didn’t decide to do that; I just did it. But look—that reflects how the two hemispheres work!

The right hemisphere controls the left side of the body. And the left hemisphere controls the right side of the body. (Yes, very weird. Reread, and hold on.)

I am right-handed. Using my right hand, my left hemisphere pins down and makes explicit—by writing notes—a tiny portion of what my right hemisphere experiences as an overwhelming, continuous a-ha. By “re-presenting” some of that into my own words (the notes), I fix that much narrower but clearer understanding into memory and consciousness.

(What if I were left-handed? The notes I’d take might (or might not) be different from those I’m taking as a righty. But the left hemisphere would still be in charge of breaking down what I’ve read into component parts, i.e. facts. The right hemisphere would then direct the left hand to write down those facts in mysterious ways, its wonders to perform.)

Those flashes stimulated by taking notes? They come from my right hemisphere. How fitting that they end up on the left side of my comp book—scrawled, not bothering to stay within the lines, messy in the way of emerging first drafts.

I didn’t “choose” to use only the right page of the comp book for notes on the text, leaving the back (left side) blank. I don’t “know” why either—I can’t explain with words. I guess my right hemisphere just “knew” what she was doing and did it, without bothering to tell my left, thus leaving the “choice” unarticulated and unacknowledged. Another fascinoma: most of what we do is “decided” by the right hemisphere, out of awareness.

How Well Do the Two Hemispheres Work Together?

The right hemisphere transmits into awareness our visceral and sensory experience of being alive in an unbroken flow of moments, each experienced as new, unique and original. The right sources all creative activity (such as a rough draft), and its raison d’etre is the experience, not the product. The left enables us to make things (such as a revised, polished blog post), its raison d’etre is the product, and its agenda is power.

When the two hemispheres are functioning at their complementary best, the right side transmits undifferentiated impressions to the left side, which “unpacks” some of that into component parts, then returning those parts to the right. The right hemisphere doesn’t just add those back as a simple sum: 1 + 1 = 2. Instead, the right incorporates the left’s contribution by transforming it into a new whole—an a-ha, that is greater than the sum of the parts.

But the two hemispheres don’t necessarily function complementarily. The left doesn’t want to cede control over its product. While the right continuously transmits impressions to the left, the left is mostly ignorant of the right, and thinks it is interfacing directly with reality. For instance, if you touch a hot burner on the cooktop, the right hemisphere will pull your hand back before the left can shout the word HOT! But the left will still think it got there first. We’ll inadvertently agree because we can hear it shouting in our mind’s ear. Like the left hemisphere, we are often unaware of the right hemisphere directing us because the right can’t shout—it doesn’t use words.

Thus the two hemispheres are often at cross purposes, working against each other. Have you ever felt divided, conflicted, vowing to do one thing while your body does another (or vice versa)? Guess what? You do have two minds! And they don’t get along that well.

I do not know

what to do: I

am of two minds

~Sappho, 630 – 570 BC