Why Does The Brain Have 2 Halves?

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You’ve probably heard the expression that someone is “right brained” or “left brained” before. But what does that mean?

It has to do with the fact that our brains are divided into two halves, or hemispheres. There’s a popular notion that one half of the brain (the right side) is devoted to emotions and creativity, while the left half handles logical and analytical thinking. The truth is a little more complicated than that. But this common conception raises a larger question: Why is the brain divided into two halves in the first place? What purpose does it serve?


The Halves of the Brain, Explained

There’s some truth to the idea that different parts of the brain are associated with certain ways of thinking. In addition to the hemisphere split down the middle, the brain is divided up in smaller ways, and certain regions within both hemispheres are dedicated to specific mental tasks.

The right side of the brain specializes in facial recognition and emotions, while the left hemisphere handles things like language and speech ability. As you can see, there’s a degree of truth to the “left vs right brain” dichotomy, but the popular understanding of this concept is incorrect. The brain is much more complex than that.

There are certain sections of the brain which focus on things like pattern recognition, special awareness, abstract thinking, and more. But why are certain parts of the brain devoted to specific cognitive tasks?

Recent reports by neuroscientists indicate that there appear to be evolutionary advantages to assigning specific kinds of cognition to specific areas of the brain. Their research, published in the April 2017 edition of the medical journal Neuron, reports that this makes it easier and more efficient for the brain to perform a given task if a specific area of the brain is devoted to it. This also makes it easier for the brain to multitask, which manifests itself as our normal perception of reality in which, for example, we can speak, recognize faces, places and objects, and maintain our balance all at the same time, without really making an effort to do so.

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Asymmetry in the Brain

It’s normal and natural that the sides of the brain aren’t identical. Even with something less intellectual, like motor functions, this can be demonstrated by the fact that most people are either right-handed or left-handed, as opposed to being ambidextrous.

This hemispherical division of the brain isn’t unique to humans. Almost all animals have this partitioning of the brain down the middle, and a division of responsibilities along specific regions of the brain.

It’s important to note, however, that despite this division of the brain into halves and sections, there are constant communications between all aspects of the brain. Our perception of reality is not “split” at all. All of these parts of the brain working in harmony with each other is what allow you to experience the world as you do. The cluster of neural fibers called the corpus callosum that connects the left and right sides of the brain is what make it possible to efficiently process and share data between different parts of the brain.


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While neurology is a mature field of medical science, the truth is that we still have much to learn. The human brain is a dazzlingly complex piece of biological equipment, with some 86 billion neurons, all firing and receiving synapses from the time we are in the womb until the last minute of life. As the field continues to advance, we will learn more and more about the complexities and evolutionary advantages our split brains offer us. Until then, take a moment to appreciate the gift that nature has given you—then pick up a book and put that brain to use!