What If Humans Only Had A Left Brain? | Unveiled

<h4>

What If Humans Only Had a Left Brain?</h4>

The human brain has been described as the most complex known structure in the entire universe. It’s the hub for everything we do, see, think, feel, experience, learn, and remember. Although it’s held inside the thick bone of our skulls, it’s also the only reason we’re ever able to understand anything that happens to us in the outside world. And yet, from some perspectives it’s actually quite a simple entity. A near symmetrical organ with distinct halves that combine to make the whole. So, what happens if that basic setup falls apart?

This is Unveiled, and today we’re answering the extraordinary question; what if humans only had a left brain?

Physically speaking, what is the brain actually made of? In the past, some have wrongly referred to it as a muscle - which it isn’t. What it is is mostly fat. It weighs about three pounds and, according to Johns Hopkins Medicine, “is about sixty percent fat. The remaining forty percent is a combination of water, protein, carbohydrates and salts”. Based on only that description, however, you might imagine the brain to be something of a bland and lifeless blob of nothing much. But, really, we know that all of that matter is arranged in such a way so as to produce something incredible. The brain contains enormous amounts of nerves and blood vessels, billions of neurons and synapses, along which all of life is processed. It has an outer layer of gray matter covering an inner core of white matter. What’s key for today’s question though, is that it’s near-perfectly split into two.

The mysteries of the left and right brain - the two hemispheres of our cerebral organ - have been a key focus in neurological study for centuries. The fact that there are two halves has been known since as far back as in ancient Rome, although many of the greatest strides in our understanding have been made in the last two hundred years, or so. The two halves are connected by a dense bundle of nerve fibers called the Corpus callosum, although there are some split-brain patients who have had their Corpus callosum severed - often as a last resort to treat severe epilepsy. Much of what we know about how each of the brain’s hemispheres function is then derived from studies involving split brain patients. The most famous of all were carried out by the American neuroscientist Roger Sperry, beginning in the 1960s… with Sperry’s work then continued by many of his students, among them Michael Gazzaniga and Jerre Levy.

Such studies have shown that each side of the brain is somewhat specifically responsible for certain functions and abilities. However, the idea that any one person can be more influenced by one side over the other - i.e., you can be more left-brained than right - is now generally regarded to be a myth. In the standard setup of the human brain, with both sides fully linked by the Corpus callosum, scans show that each side is called upon in essentially equal measure. As a result, and in the real world, you really need both sides to survive. For this what if scenario, though, we’re imagining that your body does find a way to carry on with only the left. How different would your life be? And how much can that tell us about the way the brain works?

The left brain is typically referred to as the logical side. Most language functions are attributed to sections of the left, including fundamental vocalization skills. The left brain is said to be a communicator, an analyser, a problem solver. It specializes in facts and sequences, but could struggle with more abstract things like emotions. While contemporary research has shown that it’s not quite so black and white as left equals logic; right equals creativity - that the relationships are much more nuanced than that - we can predict that if we were somehow only left brain beings, then there’d be some things we’d be great at, and some that we’d find difficult if not impossible. 

Researchers can demonstrate this via some quite simple visual tests conducted on split-brain patients. What’s important in every test like this is that the left brain controls the right side of the body, and vice versa. In this way, it’s been shown that if a visual cue is presented to the right visual field, then a patient is easily able to say what they’ve seen. The left brain, containing the key areas for language and speech, does this almost automatically. However, if the same visual cue is presented to the left visual field (and therefore processed by the right brain, only) then the same patient can’t vocalize the image. In our particular hypothetical situation, then, perhaps humans would be constantly talking if they had only a left brain. Writing, as well, as this is another ability found to be primarily guided by the workings of the left hemisphere. For so long as the left brain still only controlled the right side of the body, though, we would all inevitably be right-handed. More broadly, it would seemingly be a world of unapologetic speech and script. However, while that may sound like something of an ultra-expressive utopia, there would more than likely be plenty of problems.

Michael Gazzaniga, a psychologist at the University of California, Santa Barbara and, again, a former student of Roger Sperry,  has devised what he calls the left-brain interpreter. This is a neuropsychological model that might go some way to explaining why humans do some of the things they do. Studies presided over by Gazzaniga have shown that not only can the left brain vocalize what it encounters, but it can also invent an explanation for anything the body is doing based on right brain stimulation. For example, if the right brain is told to walk (and so the subject gets up and walks to the door) all while the left brain is unaware of what’s happening, then the subject - when questioned - might still provide an explanation for what they’re doing. For example, they might say “I’m going to check that the door is unlocked”, when actually they never had any inclination to do that. In isolation, this might be seen as bizarre, but as a repeating pattern it could lead to various unwanted effects - including confusion or bias. In a revised 2002 article for “Scientific American”, Gazzaniga concluded; “it appears that the inventive and interpreting left hemisphere has a conscious experience very different from that of the truthful, literal right brain”. 

On the one hand, then, the left brain’s apparent sureness - achieved via its seemingly analytical bent - might instill confidence into a person, leaving them free of such feelings as doubt and anxiety. On the other hand, however, a solely left interpretation of events could lead to overconfidence, to the continued entrenchment of harmful ideas, and even to delusion. When both halves of the brain are connected, the right serves to check the left, and vice versa. But, if the left were somehow cast adrift, then its specialisms would know no bounds. The apparently more emotionally-driven right brain might be seen to offer context to what the left brain understands. The two combined achieve a greater complexity than any one half could on its own.

All to say that it’s not as though we should ever really value one half over the other. On the surface level, we can theorize that anyone with only a left brain would be a talker, a writer, and probably quite sure of themselves and their convictions. Our hypothetically one-hundred percent left-brainer would likely excel at calculations, and at memorizing facts as though they’re data. However, they probably wouldn’t be a very imaginative talker, or a very creative writer, without an in-depth appreciation of more abstract concepts. Their memory might be great in some ways, but flawed in others - such as in remembering how any one experience made them feel. Gazzaniga’s characterization of the left brain as more “inventive” than the “truthful” right, however, then appears to turn all of that on its head. But, with context, we can see how in this case the inventiveness is more a bid to maintain logical control - rather than an exploration of the more unknowable, right brain concepts.

Over the years, however, what Gazzaniga’s work, and the work of countless others in the field, has done… is show just how intricate the inner mechanics of the brain really are. The Corpus callosum, when it is intact - as it is for most people - is like a spectacular neural highway, transporting information across and transforming it into the unique lives and experiences that every one of us has. At the same time, split brain patients are proof that you can live without it. Life is sometimes a little different, but you do at least still have both halves of your brain to call upon. 

In contrast, and in reality, living with just one of those halves probably isn’t possible. But, as a thought experiment, it shows exactly what either side contributes. Because that’s what would happen if humans only had a left brain.