Brain Asymmetry and Psychological Processes

Did you know that the left and right hemispheres of the brain exhibit certain anatomical asymmetries? These particularities translate into varied psychological processes that differentiate us from each other.
Brain Asymmetry and Psychological Processes
Valeria Sabater

Written and verified by the psychologist Valeria Sabater.

Last update: 07 June, 2023

Brain asymmetry demonstrates that certain functions, such as language, are carried out more optimally in one hemisphere than in the other. In fact, the organization of the brain isn’t the same in the left half as in the right. There are subtle differences, both anatomically and functionally. These have various psychological implications.

A study conducted by the Max Planck Institute states that left-right neurological asymmetry can mediate the onset of autism spectrum disorder (ASD) and also schizophrenia. The study also suggests being left or right-handed is dictated by this interesting feature. In this article, we’re going to explore some other features of brain asymmetry.

Human language is a function carried out predominantly by the left hemisphere. However, why this is the case isn’t yet fully understood.

Brain asymmetry

Brain asymmetry defines a neurological peculiarity in which there are structural and functional differences between the two hemispheres. This affects many areas of human development. Not all people show the same anatomical shape of this organ. As a matter of fact, each human brain is unique and presents particular characteristics.

In 1864, the French neurologist, Paul Broca, discovered that this functional asymmetry caused language to be located, to a greater degree, in the left hemisphere. He also found that patients with a lesion in the left frontal lobe presented aphasia. Similarly, lateralization (being right-handed or left-handed) is linked to structural asymmetries of the cerebral cortex.

Interestingly, this particularity isn’t exclusive to the human being. Indeed, most vertebrates demonstrate it. Neuroscience highlights that brain asymmetry is a relevant area of research because it allows us to better understand our behavior and the origin of certain mental problems.

The effects of neurological asymmetry

Cerebral asymmetry affects behavioral, cognitive, and psychological domains. The impact of this anatomical and functional characteristic is such that, a study conducted by the University of León (Spain), claims there’s a need to promote neuropsychology as a mechanism to better understand learning processes in humans. Next, we’re going to explore how this neurological asymmetry affects us.

Mental conditions such as schizophrenia reveal certain brain asymmetry in areas that mediate exhaustion and lack of initiative (apathy).


As we mentioned earlier, the asymmetry of the brain could explain why people are right or left-handed. However, according to an article published in the journal, PNAS, there seems to be a genetic trigger. It seems that, while being left-handed is associated with differences in brain asymmetry, the same happens in some regions linked to language, manual control, vision, and working memory.

While in right-handers, the left hemisphere controls the dominant right hand, in left-handers, it’s the opposite.

Mental disorders and brain asymmetry

Cerebral asymmetry is a fundamental characteristic of the organization of the nervous system. It can create anatomical variations and alter the functioning of multiple neurological processes. Therefore, it’s not surprising that this biological peculiarity triggers a number of mental health problems. The most common disorders are as follows:

  • Attention deficit hyperactivity disorder. Alterations mediate sufferers’ attention problems.
  • ASD (autism spectrum disorder). The Max Planck Institute for Psycholinguistics provides relevant information in this regard. Sufferers exhibit altered lateralized neurodevelopment. However, the authors highlight the need to carry out further research and reviews to reach clearer conclusions.
  • Major depression. A study published in Biological Psychology highlights the link between major depression and brain asymmetry. It claims there’s less activity in the left hemisphere and hyperactivity in the right frontal area. This results in slowed thinking, a more inflexible mental focus, poor emotional regulation, and high resistance to change.
  • Schizophrenia. A study published in Acta Psychiatrica Scandinavica claims that patients with schizophrenia present greater asymmetry in their gray matter. This anomaly appears during a child’s neurodevelopment. It’s usually manifested as apathy, the striking lack of energy that appears in schizophrenia.

A favorite side to chew on and a favorite eye to look with

Curiously, the asymmetry of the brain makes us have a greater tendency to chew on one side and not the other. A study conducted by the University of Barcelona (Spain) states that this preference is the effect of lateralization and particularities in the neurological anatomy between the hemispheres.

Furthermore, predilections have been found in the use of sensory organs such as the eyes, with the right being the preferred one in most cases. If you want to know what your preference is, try looking through a lock. Which eye do you automatically use?

You might be interested to read David Eagleman: Biography of a Brain Expert

Do the most creative people have any brain asymmetry?

Perhaps you’ve heard that the most creative people use the right hemisphere to a greater degree. Although the scientific community sees this data as a neuromyth, given its scant empirical support, an investigation conducted by the University of Geneva (Switzerland) offers a series of arguments that partially support this idea.

However, we should clarify that creative thinking requires using a good part of both hemispheres. After all, this cognitive process demands high doses of intuition and imagination, combined with logical analysis, reasoning, reading, and language (the latter tasks are processed by the left hemisphere).

The researchers discovered that the most creative people exhibit brain asymmetry linked to the functionality of dopamine. In fact, these individuals receive a lower level of this neurotransmitter in their right hemisphere. This allows them to combine remote and original concepts to shape innovative and effective ideas.

In conclusion, there seems to be little scientific evidence for the idea that creativity is located more in the right brain area. Indeed, the results of this ongoing research are proving to be fascinating.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.