Reassessing Split-Brain Mythology

Based on a lecture by psychiatrist Iain McGilchrist, author of The Master and His Emissary: The Divided Brain and the Making of the Western World, this RSA video is a real treat. It takes a balanced, thoughtful, nuanced look at the idea that the left and right parts of the brain do in fact have different functions, even if those differences have been over done in popular conception. His opening salvo will reassure the skeptics:

The division of the brain is something neuroscientists don’t like to talk about anymore. It enjoyed a sort of popularity in the 60s and 70s after the first split-brain operations, and it led to a sort of popularization which has since been proved to be entirely false. It’s not true that one part of the brain does reason and the other does emotion, both are profoundly involved in both. It’s not true that language resides only in the left hemisphere. It doesn’t. Important aspects are in the right. It’s not true that visual imagery is only in the right hemisphere, lots of it is in the left. And so, in a sort of fit of despair people have given up talking about it, but the problem won’t really go away. Because this organ, which is all about making connection is profoundly divided. It’s there inside all of us, and it’s got more divided over the course of human evolution.

Paradoxically, McGilchrist then goes on to a detailed assessment of the different functions of the left v. right brain — keeping in mind all the while, that this is a schematic assessment with all kinds of exceptions and qualifications.

Typical of such schemes, he points out that the right brain seems dedicated to sustained, broad, open, vigilant alertness, to connection with others, while the left tends to focus narrowly, sharply, attends to detail, with a tendency to focus on already known, factual information. Such schematic functions seem to apply to animals as well as to humans. It seems that McGilchrist’s view is the right brain has been given short shrift. He notes: “The intuitive mind is a sacred gift and the rational mind is a faithful servant. We have created a society that honors the servant, but has forgotten the gift.”

Less typically of such schemes, he notes the important of the frontal lobes, and how they make humans different from other animals. The purpose of the frontal lobes is

to inhibit the rest of the brain, to stop the immediate happening, so standing back in time and space from the immediacy of experience. And that enables us to do two things. It enables us to do what neuroscientists are always telling us we’re very good at which is outwitting the other party, being Machiavellian. And that’s interesting to me because that’s absolutely right. We can read other people’s minds and intentions and if we so want to we can deceive them. But the bit that’s always curiously left out here is that it also enables us to empathize for the first time. Because there’s a sort of necessary distance from the world. If you’re right up against it you just bite. But if you can stand back and see that other individual is an individual like me who might have interests and values and feelings like mine then you can make a bond.

So there you have another wrinkle — the important role of the frontal lobe in empathy. The video is accompanied by some amusing and very well done animation and contains a great deal of interesting food for thought. Highly recommended.


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Clinical Psychologist practicing in the Los Feliz neighborhood of Los Angeles, California.

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