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What is Brain Lateralization?

By Dr. Usmarah Hussain

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What is Brain Lateralization

Have you heard people say how left-handers are generally smarter than right-handers? Did you ever wonder where this concept comes from, and more importantly, why different people have different hand preferences? It all lies in the concept of brain lateralization.

Scientists have long known that the human brain has two distinct halves with marked differences. These differences, in some way, connect with handedness and many other functions of the body. The theory of brain lateralization came into being as an attempt to solve this complex story and understand how the two halves of the brain create differences in everyday traits and functions.

Not familiar with what brain lateralization is? Keep reading the article to find out.

Exploring the Concept of Brain Lateralization

The human brain is an intricate yet extremely complex organ with millions of neuronal connections, making consciousness possible. While this brain may look exactly similar from every angle, it is, in fact, quite asymmetrical, with the left side of the brain performing different functions than the right. This asymmetry is what we call lateralization.[1]

To make the matter clearer, the brain is divided into two lobes or hemispheres: right and left. Both hemispheres meet in the middle through a thick structure comprising nerve fibers called the corpus callosum. Each of the hemispheres has certain functions localized to it and may perform them much better when compared to the other.

Brain Hemispheres

For instance, the brain’s left hemisphere contains Wernicke’s and Broca’s areas that specialize in speech production and language comprehension. What this means is the left side predominantly controls how we speak and comprehend others. It is also important to remember that the human brain always operates contralaterally. This means the right side of the brain controls the left side of the body, and the left side controls the right, much like a crisscross pattern.

What’s the Fuss about Brain Hemispheres? Key Functions

Both hemispheres of the brain are equally crucial in monitoring and regulating several key functions of the body. Let’s look at these functions in more detail.

The Role of the Left Hemisphere

The left hemisphere directly controls the right side of the body while constantly communicating with the right one to ensure adequate information processing. While it is a bit difficult to identify the exact locations of brain functions, the neuroimaging techniques have given us a general estimate of which functions happen in what areas.  For instance, if you see a vehicle approaching you in your left visual field, the information goes to the right hemisphere first, from where it goes to the left hemisphere.

The left hemisphere is involved in the following functions:

  • Controlling movements on the right side of the body. It contains the left motor cortex that regulates how different parts of the left body, such as the left leg and hand, move.
  • It contains Broca’s area that regulates speech production. Wernicke’s area is also located in the same hemisphere, which helps with speech comprehension.[2] The presence of these two areas makes the left hemisphere specialize in language. When you are talking, Broca’s area is working hard to produce speech, and any damage to this area can make speaking difficult. Wernicke’s area comes into use when you listen to someone speak, and it helps you understand what they are conversing about. Any damage to this area can make it difficult for you to understand and comprehend any discussion.
  • Logical processing, such as reading, writing, and making calculations. Experts suggest that most people have a dominant left hemisphere which is why they use their right hand to write.
  • Formation of memory association
  • Perceiving and regulating positive emotions and behaviors in others
  • Paying attention to specific information

The Role of the Right Hemisphere

Due to the contralateral functions, the brain’s right hemisphere controls the human body’s left side. It specializes in many functions, such as:

  • Visual and auditory processes, such as the ability to hear melody and pitch, musical proficiency, and the ability to identify differences in intonations in conversations. These skills are a major reason why experts believe the right hemisphere to be the “creative hub” of the brain.
  • Controlling movements on the left side of the body. It contains the right motor cortex that regulates movement in the left leg, hands, and other parts.
  • The ability to recognize faces
  • Regulating emotions and perception of these emotions and behaviors in others
  • Spatial awareness and tasks

Evaluation of Lateralization Psychology

Now that you have familiarized yourself with lateralization and the different roles of the right and left hemispheres, it can be interesting to apply the concept to justify the differences between males and females.[3] Males and females have many physical differences, alluding to the distinctions between the cognitive abilities and behaviors of both sexes.

  • Upon comparing the brains of males and females, experts have found that the latter show lesser brain lateralization for language, indicating that they process and perform language feats much better than males. Why? Because they show bilateral activity in both hemispheres of the brain for language skills.
  • Males, on the other hand, have higher lateralization when it comes to language skills. [4] Studies even suggest that their brains are better at carrying out spatial tasks than females as they utilize one hemisphere more dominantly.

Advantages of Brain Lateralization

There have been many advocates of brain lateralization through the decades, demonstrating how the phenomenon can allow the mind to carry out more complex commands without compromising its baseline functions. Following are some benefits humans can enjoy due to brain lateralization:

Increased capacity for neural processing

By designating different functions to different hemispheres, lateralization frees up enough space in the other hemispheres to take up more tasks.

Enhanced multitasking

Studies have found that lateralization also allows the brain to pick up two separate tasks and perform them with higher efficiency at the same time. Keeping this finding in mind, it is widely believed that lateralization improves the efficiency of the brain to perform cognitive tasks that require simultaneous attention from different hemispheres.

Enhanced Multitasking


Although not in humans, brain lateralization in other animal species helps them survive by helping with foraging and prey capturing. The right brain hemisphere in such animals specializes in expressing aggression and fear.

Disadvantages of Brain Lateralization

So far, you must be fascinated by how brain lateralization works and how it can help humans achieve so much and with so much efficiency. But while we are on this subject, let’s not forget that everything has two sides. In addition to tons of benefits, the hemispheric lateralization theory also comes with a few disadvantages.

Less human trials

Most studies assessing lateralization have been performed on animals. Human trials are not sufficient at the moment, which may make it difficult to know whether similar results also apply to humans.

Difficult to generalize

The studies performed on brain lateralization mostly used split-brain research, i.e., their findings were focused on the participants and hard to apply to the general population.

Lateralization may change with age

Some studies have even found that lateralization, such as speech lateralization, may increase up to the age of 20, flatten out for the next five years, and gradually decline until 70 years.

Lateralization can be challenged

More recent research has proven that the brain can adapt and cause changes in its lateralized specialties.[5] For example, a study negated the popular myth that language processing only takes place in the left hemisphere by proving that some people can also develop the ability to speak using the right hemisphere.

The Concluding Thoughts

Brain lateralization is an exciting concept that allocates two different hemispheres as specialists of different functions. The advocates of the theory strongly argue how this phenomenon greatly helps people get on with daily tasks with more ease and efficiency. However, like every other theory, brain lateralization also has limitations and drawbacks. Fortunately, research targeting this theory is ongoing, and more information will be revealed to us in due time.

Frequently Asked Questions

What do you mean by brain lateralization?

In simple words, brain lateralization indicates a concept that certain brain functions are performed better by one brain hemisphere than the other. This concept is based on the fact that the human brain is asymmetrical and has differences in structure and functions across both hemispheres.

What is a good example of brain lateralization?

A good example of brain lateralization is one-sided preferences, such as using the right or left hand for eating, drinking, writing, or performing all other essential tasks.

What does lateralization of function psychology mean?

The term indicates the differences in left and right brain hemispheres in terms of specialized areas of function. For example, the right hemisphere primarily specializes in creative skills, whereas the left hemisphere controls language.

Why is brain lateralization so important?

Thanks to brain lateralization, we can divide tasks for specialization and free up the rest of the areas to take care of additional tasks at the same time. In simpler words, it increases the capacity of our brain to function more optimally and focus on different tasks simultaneously.


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