Brain hemispheres: myths and realities

Is the left hemisphere analytical and the right hemisphere creative? Science sheds some light on this popular myth.

On the subject of the cerebral hemispheres it is common to hear some phrases like these: "If you are a person with great creativity, you use much more of the right hemisphere." or "If you are an analytical person you use the left hemisphere more".... However, everything related to these two parts of the brain is much more complicated than these simplifications.

In this article we will see what the cerebral hemispheres are, what their characteristics are, and how they differ, taking into account that these components of the central nervous system allow us to understand a good part of what happens in our brain, since they determine how it functions.

Cerebral hemispheres: what are they and how do they work?

When observing a human brain, one of the most striking things is that sort of crack that separates the two halves of the brain, running from the front to the back.

Its existence is not causal, and it gives clues as to how the brain works, a set of organs in which the cerebral cortex (the outermost part of the brain, with roughness) is intended to occupy as much of its surface as possible.. Thus, the existence of the cerebral hemispheres allows more cerebral cortex to extend between them.

Why has our brain evolved to give so much importance to the cerebral cortex? This is because it is in the cerebral cortex where most of the neuronal bodies are concentrated, that is, its most important part, where the nucleus is located. The grouping of neuronal bodies forms what is known as gray matter, associated with complex brain activity.

In recent years, a multitude of courses, tests, e-books and books have appeared on social networks explaining "the big differences between using one or the other hemisphere of the brain", and even tips and exercises to achieve a "perfect balance". perfect balance (sic) between both hemispheres.

However, the question arises: Is it true that we tend to use one hemisphere more than the other? Is this conception that each hemisphere performs different functions accurate? To answer these questions, it is necessary to know what the cerebral hemispheres are, if only from a basic definition.

Anatomy of these hemispheres of the brain

The cerebral hemispheres are the two structures into which the brain is divided, and are separated from each other by the interhemispheric fissure (or intercerebral fissure). These two bodies belonging to the Central Nervous System are very similar to each other, and are practically symmetrical, although there are some differences in their proportions and folds.

On the other hand, the hemispheres of the brain are connected to each other by the corpus callosum and other similar commissures; it is through these parts of the brain that information crosses from one to the other.

The anatomy of the brain and the way it is divided into two hemispheres gives us some clues about the functioning of this set of organs.

On the one hand, it is known that the cerebral cortex exists because its surface accumulates neuronal somas, that is to say, that in these areas the bodies of these nerve cells, their main structure and where their nucleus is located, are piled up. The human brain has been giving priority to the cerebral cortex. to give us more capacity to process information, and for this the best way is to make the cortex have folds, to have more surface, and the interhemispheric fissure can be understood as a consequence of this phenomenon: it is still a very deep fold.

But as all parts of the brain need each other and cannot operate entirely in parallel, at the bottom of this fissure there are structures such as the corpus callosum, which act as a bridge between the two sides of the brain.

Pocket neurosciences: oversimplifying

It seems to be common knowledge to many people that the right hemisphere is linked to the right brain. the right hemisphere is linked to the processing and expression of emotions, both internal and external.both internally and externally (this hemisphere is linked to empathy) while, on the other hand the left hemisphere is in charge of language processing, rational logic and analytical capacity..

However, this knowledge, although for some reason it has taken root in the collective culture and everyone seems to take it for granted, is not entirely true. It is a widespread myth that bears little or no relation to reality and the available scientific data. and with the available scientific data. Without going any further, the right hemisphere also performs functions associated with the processing of some aspects of language, such as intonation and intensity.

On the other hand, the brain has a great capacity to adapt to challenges, and each hemisphere is able to "learn" to carry out functions performed by parts of the right hemisphere. perform functions performed by parts of the opposite hemisphere if these regions are damaged.. This faculty is called brain plasticity, and it shows us to what extent the functioning of our brain is not fixed.

Science and research to shed some light on this issue

The data and information on the issue of functional differences in the hemispheres of the brain come from neurological studies from the early 1970s on patients who had the corpus callosum (the fibers connecting the two hemispheres) cut as a shock intervention to treat epilepsy.

Some of the academics and researchers who contributed most to the study of the brain in patients without corpus callosum were the psychologists Roger W. Sperry y Michael Gazzanigawho discovered that the two halves of the brain developed their processes independently and with different dynamics.

However, it should be noted that in healthy people whose cerebral hemispheres are correctly connected via the corpus callosum, perceptual and executive processes develop independently of each other, perceptual and executive processes develop in the brain as a whole.The different brain regions and hemispheres share information through the corpus callosum.

Although certain regions of the brain are more focused on certain functions, normally a very small part of the cerebral cortex is not totally irreplaceable: if it is injured, another will take over those functions that have been "orphaned". The same is true for the hemispheres of the brain in general.

Currently, neuroscientists (neurologists, biologists and psychologists) are trying to understand how this complex coordination between hemispheres takes place. This is why theories such as that of brain hyper-modularity, supported mainly by evolutionary psychology and according to which the brain is a set of specialized parts that work more or less in parallel, are not widely accepted by the scientific community. The brain is what it is because millions of neurons in it coordinate with each other.The right hemisphere, creating activation patterns that must be understood as a whole.

Creativity, right hemisphere. Are you sure?

It should also be taken into consideration that the type of daily life tasks that require "a particular hemisphere" according to popular belief, does not entirely fit the categorization left hemisphere / right hemisphere.

One of the skills with which it is easiest to disprove the myth is creativity. While it is easier to assume that creative tasks take place in the right hemisphere and repetitive and analytical tasks in the right, the reality is that such tasks are more complex and involve the brain in a more global way than we might expect if we believe the myth.

Moreover: "being creative" can take many forms, it is too open a concept to confine it to one easily recognizable task as a process within the human brain.

In fact, there is a study that compares the brains of students "of letters" (philology, history, art) with students "of science" (engineering, physics, chemistry)... and the results are surprising. We explain it here:

• Brain differences between "letter" students and "science" students.

Studies on the subject

Several researches point out that the right hemisphere has a greater role in the moments when we have a great intuition.. In fact, a study published in PLOS found that right hemisphere activity was greatest when the subjects tested were trying to solve a task intuitively, with little time for reflection.

Other research revealed that a brief exposure to a clue that gave some clues to solve a puzzle was more useful for the right hemisphere than for the left hemisphere. The right hemisphere was more clearly activated, leading some of the participants to solve the task.

However, it should be clarified that the insight (the process of internalization or internal understanding) is only one aspect of creativity. For example, the ability to explain stories would be another creative aspect. Here we already find an important schism: studies that evaluate the influence of each hemisphere in certain tasks have revealed that the left hemisphere is the one that has the most influence. is the left hemisphere the most involved in the process of inventing stories or tales, while the left hemisphere is the most involved in the process of inventing stories or tales.while the right hemisphere is in charge of finding an explanation for the story. This curious distribution of functions was called the "interpreter phenomenon" by Gazzaniga.

Simple myths that quickly catch on in people's minds

In an overview of the cerebral hemispheres and their (not so) differentiated functions, Gazzaniga described, in a paper published in Scientific Americanthe left hemisphere as "inventor and interpreter" and the right hemisphere as "truthfulness and literalism". Adjectives that contrast with the popular conception of each hemisphere.

In any case, it is clear that virtually no cognitive process is based in very delimited parts of the brain. Everything occurs in an organic network of interconnected nerve cells, which do not understand differentiations and closed categories established by human culture. That is why we must keep in mind that the differences between the cerebral hemispheres are relative, not absolute.not absolute.

Concluding: between simplifications, exaggerations and corners of reality.

The scientific evidence does not correspond to the myth that the left hemisphere is linked to logical processes and the right hemisphere to the creative realm. If this is so, why do people, and even professionals in psychology or neuroscience, think that the left hemisphere is neurosciences keep repeating this mantra?

One of the possibilities to understand how a myth expands and consolidates itself in the collective culture is its seductive simplicity. People are looking for easy answers to questions that, right from the start, are quite naïve: "What type of brain do I have?What kind of brain do I have?”.

With a quick search on Google or on the various social networks, a person without scientific knowledge and with this personal concern can find applications, books or workshops to "improve their weak hemisphere". When there is a demand, the supply soon appears, even if the scientific basis on which the matter is based is rather debatable. As in this case, where simplification makes this information border on falsehood.

Thus, it is difficult to fight against an erroneous belief system, since the complexity involved in the functioning of our brain cannot be summarized in a brief basic outline. Nevertheless, psychology and mental health professionals and neuroscientists must be the ones to report rigorously on how our brains work. should be in charge of rigorously reporting and debunking these myths and simplifications..

Bibliographical references:

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