The brain is at the base of everything we are and do.

It is the seat of our personality, responsible for our emotions, and how we feel during the day; but it is also the organ that enables us to chew gum, kick a ball, go out for coffee with a friend, read a book, plan where we will go on vacation, prepare a practical work for the university, fall in love, choose a church to marry, and thousands and thousands of other things. From the apparently smallest and most trivial action to the most sophisticated mental processes .

To be able to do all this, it would be logical to think that the human brain is an organ perfectly prepared to rationally and consciously process all the information that comes to us from the environment. However, the brain does not always work on the information that we consciously process , and there are even times when the mental processes that guide our behaviour spontaneously generate lies.

Lying brains and short-circuit trickery

The first thing we must know to better understand why the brain does not have to work from the objective information that comes to us through the senses is that the brain is divided into two large structures that are known as cerebral hemispheres.

The left hemisphere and the right hemisphere are, in appearance, morphologically equal, as if one were the mirror image of the other. They are located on both sides of the head, slightly separated by an external fissure, but connected on the inside by a thick bundle of nerve fibers called the corpus callosum.

Left hemisphere: the rational and analytical part

The left hemisphere is the seat of analytical understanding, numerical understanding and logical analysis . This is also the region responsible for language.

Right hemisphere: non-verbal and emotional information

The right hemisphere is more concerned with processing non-verbal and affective language information , such as the tone of voice, rhythm and the emotional meaning of what you are hearing.

The corpus callosum complements both hemispheres

As can be seen, these differences are complementary. The two hemispheres form a whole; the brain works as a unit , and it is precisely the corpus callosum that allows communication and permanent interaction between both structures. Another fact that is not minor: the left hemisphere controls the right side of the body, and the right hemisphere controls the left side.

Let’s look at a simple example. If we close right and observe the photograph of a tulip, the stimulus travels preferably to its left hemisphere, and from there it crosses to the right hemisphere through the corpus callosum. In this way, our brain perceives the image in its different aspects but in an integral way. It obtains a complete understanding of what it is observing; we can say without a doubt that it is a tulip. We are able to describe it and even remember everything we know about that flower .

But… what does this have to do with deception?

A few years ago, a group of scientists noticed a number of strange phenomena in patients diagnosed with epilepsy and who had recently undergone an operation known as corpus callosum ablation .

Epilepsy reveals something important

Of course, there are different types of epilepsy and of different magnitude, most of them controllable with medication. But in severe cases, when the frequency and intensity of the seizures are very high and all possible treatments have been exhausted, there is a last resort .

This is a surgical procedure in which the corpus callosum is severed, leaving the cerebral hemispheres permanently disconnected. Of course, this does not cure the disease, but at least it prevents the epileptic seizure that starts in one of the brain hemispheres from taking over the opposite hemisphere through the corpus callosum.

But it turns out that the procedure leaves some unsuspected sequelae, a series of side effects as strange as they are intriguing. When patients were asked why they had made a certain decision, and depending on which hemisphere processed the information, they could lie openly in their answers, and what was worse, they seemed not to be aware that they were doing it .

Some examples of ‘neurological lies’

If an ordinary person is asked to perform a particular action, such as closing his eyes, and then asked why he has done it, he will naturally respond that he has simply obeyed the order given to him. But that expected response, sincere and spontaneous, changed dramatically when the neuropsychologist leaned over the recently operated patient and whispered the order into the left ear, and then asked him for the reasons for his behaviour, but into the right ear.

In that case, to everyone’s surprise, the patient gave a false answer .

“My head hurts a little, and I need to rest my eyes,” I could say calmly, with the assurance of one who knows he is honest and is telling the truth.

“Raise an arm,” you could command the left ear. “Why did you do that?” he would then ask the right ear. “Well, I’m a little tense and I needed to stretch,” the patient would answer as plainly as possible.

What was going on?

Let’s go over it. The information collected on one side of the body travels to the contralateral hemisphere on the opposite side. If certain information enters through the left eye or ear, it travels to the right hemisphere, and then integrates with the rest of the brain by crossing the corpus callosum.

We also know that language is a well-lateralised function, and that it is located, to a large extent, in the left hemisphere. It can be said, simplifying the subject a little, that the right hemisphere of the brain is a mute hemisphere .

If we combine these two skills, we have the answer to the problem.

When the hemispheres are disconnected from each other…

If the bridge connecting the two halves of the brain is dynamited, the epileptic seizure is restricted to one of the hemispheres. But the same thing will then happen with any information entering through the senses .

Any instructions the experimenter might give the patient were trapped in the right hemisphere. That is, this side of the brain knew the true reasons for the requested action, but when the patient was asked, he could not verbalize them, since the language areas were in the other half.

On the other hand, the left hemisphere can speak, but it does not know what is happening. It has followed the individual’s behavior, because when he touched the tip of his nose or stood on one leg, both eyes monitored what he was doing, even though he could not tell why.

However, and here comes the surprising thing, far from humbly admitting its lack of knowledge, from accepting that it does not have the answer to everything it observes, the left hemisphere ventures to give an explanation , which in principle may sound reasonable, but which in reality is far removed from the true motives that gave rise to the behaviour.

“Why did you start singing?”, the patient was asked after giving the order to the right hemisphere.

“Suddenly that tune came to mind,” replied the left hemisphere. Or “I think I’m especially happy today.”

To the question: “Why is he scratching his head”, the patient with the split brain hemispheres looked in surprise at the man in the white coat who was evaluating him and replied, with a certain disdain: “Because it itches, what else could it be?

Beyond the anecdote

In the light of these discoveries, it is legitimate to think that one of the many functions of the left hemisphere is the interpretation of reality. The justifications these people make for their actions are the result of the efforts the brain makes to find meaning in what it is observing.

The human brain has evolved to help the individual understand and adapt as best as possible to the complexity of a changing world. For this reason, one of its main functions is to interpret reality, formulate and put forward theories that can explain the vicissitudes to which we are exposed during the course of our lives.

Sometimes these theories are true and fit well with reality, but everything seems to indicate that most of the time they are just mere speculations that are nevertheless taken as valid by the person , since their acceptance contributes to create certainty in a world full of mysterious phenomena. Thus, the sensation of control over the uncontrollable appears.

Thus, the left hemisphere is a tireless manufacturer of rationalizations, illusory arguments created to satisfy one’s own expectations and make this world a little more predictable. And what is valid for external stimuli, that is, everything that enters through the sensory channels, is also valid for internal stimuli, that is, thoughts.

Custom-made realities… or just lies

The brain collects information from the world through the five senses, but it is also true that it does not need sight or hearing to generate thoughts. And thoughts, moreover, are the raw material for mental representations, that cumulus of explanations with which we justify everything we are and do, both to ourselves and to others.

We have an explanation for everything but… Is that the real explanation? Or is it just one possible interpretation among many?

Why do we buy one brand of jam and not another? Why do we go to the cafeteria on the other block and not the one on the corner? Why do we opt for a two-door vehicle and not a four-door one? Why do we like Mozart and not Beethoven? Why do we prefer Mar de las Pampas to go on holiday instead of the Cordoba hills? Why do we get married to Fulana and not Mengana? Why did we decide to study law and not medicine?

These are all questions that we can usually answer easily, but are our answers reliable?

We don’t really know why we do what we do , and what’s worse, we dismiss the external influences that may have pushed us to do this or that.

On other occasions, the exact opposite occurs: we overestimate factors that are barely related, attributing to them a weight or power that is not such. This is what often happens when we undergo a certain treatment, with a certain amount of positive expectations.

Simply believing that therapy will help us feel better about ourselves, or lose weight, or control the anxiety that afflicts us, makes us experience a much more significant improvement than we might objectively realize. And the more time and money we invest, the more convinced we are of the benefit.

In conclusion

How can we be sure, after knowing these experiments, that the explanations we go through in life are nothing more than the result of a part of our brain willing to give an opinion on everything and obsessed with arguing about what is happening to us?

Well, my friend reader, now you know that we cannot take our own beliefs and thoughts too seriously , and this includes all those “certainties” about ourselves and others.

The history of humanity shows the harmful consequences of letting ourselves be carried away by fanaticism and apparently unquestionable ideas. We must always try to keep in mind that our worldview, the way we see the world, is only one possible “interpretation”, but not necessarily the only one. To the extent that we allow ourselves to doubt and encourage ourselves to dive into questioning, we will slowly but inexorably come closer to the truth.