What Makes The Human Brain So Special?

Some characteristics of our brain are absolutely implausible.

The human brain is exceptionally unique, it has very complex characteristics in relation to other animal species, including our phylogenetic cousins, primates. 

The capabilities of human beings are highly specific to our species: we can think in very complex terms,  be creative and create technological artifacts that make our lives easier, and furthermore, we are the only species with the ability to study other animals and their behavior. .

Why are we so special? The human brain …

For years the scientific literature postulated that cognitive ability was proportional to the size of the brains . This is not entirely correct, since two mammals with similarly sized brains, such as a cow and a chimpanzee, should have behaviors of equal complexity, which they do not. And what is even worse: Our brain is not the largest there is. In any case, our brain, despite not being the largest, is the best in terms of its cognitive capacity.

Apparently, the special quality of our great cognitive capacity does not come from the size of the brain in terms of its mass, but in terms of the number of neurons it contains. And this is where we find a study by Suzana Herculano-Houzel, a Brazilian neuroscientist, who was entrusted with the task of determining the number of neurons in the human brain.

Before their research, the vast majority of  neuroscientists argued that the human brain had 100 billion neurons. The truth is that this figure was never determined in any study and was a norm for years in the scientific literature. 

Thus, Suzana Herculano-Houzel, through a method designed by her, manages to determine the final figure for the number of neurons in the human brain: 86,000 million neurons in total, of which 16,000 million are in the cerebral cortex (cortex involved in complex cognitive processes). And by applying the same method to the brain of different mammals and comparing them, he discovered that the human brain, despite not being the largest in terms of mass, is quantitatively so in the number of neurons it has, even with primates , with whom we share many of our genetic load (97%). And this would be the specific reason for our cognitive abilities.

Why did the human being evolve to this surprising complexity?

From this, other questions arise: How did we come to evolve this surprising number of neurons? And particularly, if primates are bigger than us, why don’t they have a  bigger brain with more  neurons ?

To understand the response to these situations, one must compare the body size and the brain size of primates. Thus, he discovered that, since neurons are so expensive, the size of the body and the number of neurons offset each other. So a primate that eats 8 hours a day can have a maximum of 53 billion neurons, but its body could not be greater than 25 kg, so to weigh much more than that, it must give up in terms of the number of neurons.

From determining the number of neurons that the human brain has, it is understood that it needs a huge amount of energy to maintain it. The human brain consumes 25% of energy even though it only represents 2% of body mass. In order to maintain a brain with such a large number of neurons, weighing an average of 70 kg, we should dedicate more than 9 hours a day, which is impossible.

Humans cook food

So if the human brain consumes so much energy and we cannot spend every waking hour devoting ourselves to our food, then the only alternative is to somehow get more energy from the same foods. Thus, this coincides with the incorporation of cooking of food by our ancestors a million and a half years ago.

Cooking is using fire to pre-digest food outside the body. Cooked foods are softer, so they are easier to chew and turn into mush in the mouth, which means that it can be better digested in the stomach and allows greater amounts of energy to be absorbed in much less time. In this way, we obtain a large amount of energy for the functioning of all our neurons in much less time, which allows us to dedicate ourselves to other things beyond feeding ourselves and thus stimulate our cognitive capacity achieved with a brain of such magnitude.

So what is the advantage we have as human beings? What do we have that no other animal has?

The answer is that we have the brain with the largest number of neurons in the cerebral cortex, which explains our complex and extraordinary cognitive abilities to all of nature.

What do we do and what no animal does, to allow us to reach such a large number of neurons in the cerebral cortex?

In two words: we cook. No other animal cooks its food to digest it, only humans do it. And this is what allows us to become human as we are.

From this conception, we must realize the importance of food, how food influences the maintenance of our cognitive skills and the scope that we have in achieving behaviors of enormous complexities.

So now you know: the next time your mother cooks something for you that you don’t like or you hear that someone is going to study gastronomy, congratulate them, since with their contributions they continue to make our cognitive skills continue to be just as complex.

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