Are we really ‘left-brained’ and ‘right-brained’ people?
My mother says I am a left-brained person, the opposite of her, but I don’t know what that means. Is there a left brain and a right brain?

What people mean when they say left brain and right brain is that there is a left hemisphere and right hemisphere to everyone’s brain.

The brain comprises three parts: the cerebrum, the cerebellum and the brainstem.

Your cerebrum is the largest part of your brain.

This is the one people are talking about when they say “left brain and right brain”.

This is because the cerebrum is composed of left and right hemispheres.

Both left and right cerebral hemispheres are joined by the corpus callosum, which is a bundle of fibres that transmit messages from one hemisphere to the other.

If I am a left-brain person, then does it mean that the right side of my brain isn’t functioning?

Don’t worry, both sides of your brain are definitely working, otherwise you won’t be able to function normally!

Your cerebral hemispheres are divided into four lobes each.

These lobes are further divided into different areas that control different things.

They are:

The frontal lobe This is in charge of your personality, emotions and behaviour. It’s also in charge of your judgment, problem-solving, planning, self-awareness, intelligence (how smart you are) and concentration. The frontal lobe controls your body movement and speech.

The parietal lobe This one interprets language and different words. It also allows you to sense touch, pain, temperature and other sensations. It interprets signals from what you see, what you hear, what you are going through when you move, and what you feel on your skin.

The occipital lobe This one interprets your vision in terms of colour, movement and light.

The temporal lobe This allows you to understand language, hearing and organisation of your body. It retains your memory.

Now, there used to be a theory that not everything is controlled by both brain hemispheres.

One hemisphere controls – or at least is more dominant in certain functions – and the other controls other functions.

This theory is based on research in the 1960s by neuropsychologist and neurobiologist Professor Dr Roger W. Sperry, who was also one of the two winners of the 1981 Nobel Prize in Physiology or Medicine for his split brain research.

What theory is this?

The theory suggests that your left hemisphere is in charge of certain things and your right hemisphere is in charge of other things.

Some of this is absolutely true.

Let’s take your movement for example (i.e. motor skills).

Each hemisphere controls the other side of your body.

So your right hemisphere controls the left side of your body and your left hemisphere controls the right side of your body.

That is why when people have a stroke in one side of the brain, the other side of the body is the one impaired in movement.

The theory also suggests that the left cerebral hemisphere controls speech, arithmetic, writing and comprehension.

Meanwhile, the right cerebral hemisphere controls your creativity, emotions, and artistic, musical and spatial abilities.

According to the theory, the left hemisphere is usually dominant for most people, which is why most of us are righthanded.

If you are lefthanded, it means that your right hemisphere is dominant.

So, is this theory true?

A team of neuroscientists did set out to test this “left brain versus right brain” theory.

They performed magnetic resonance imaging (MRI) on a thousand people, and it was revealed that the human brain does not favour one side or the other, nor is one side of your brain stronger than the other.

But it is true that the two sides of your brain work in concert and complement each other very well indeed.

It’s just that you don’t use one side of your brain only at any one time.

In 2023, scientists suggested that the right hemisphere of your brain helps with spatial awareness during complex mathematics, understanding of numbers containing zero, and the representation of numbers non-verbally.

It was found that the right brain also helps with understanding metaphors and irony.

So everything is a lot more complex that we previously understood.

The bottomline is that there is no true dominant side of our brain.

Some areas do function more (are more dominant) when we do certain things, but there is no absolute “only one side” function for most things that we do.

Also, not everyone’s brains work the same way.

Some people may mostly process language on the left side of their brain, while others may mostly process language on the right side, and some may do it symmetrically across the hemispheres.

So when my mother says I am left-brained, does she mean that I am righthanded? I am indeed righthanded.

Actually, I think she means it in a more personality-and-ability sense.

She probably means that you are good at things that are more verbal, analytical and logical, e.g. speaking, mathematics and the sciences.

And by this, she is probably implying that she is more creative, intuitive and imaginative.

Dr YLM graduated as a medical doctor, and has been writing for many years on various subjects such as medicine, health, computers and entertainment. For further information, email starhealth@thestar.com.my. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Neither The Star nor the author gives any warranty on accuracy, completeness, functionality, usefulness or other assurances as to such information. The Star and the author disclaim all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
Tell Me About,Brain
The answer is that the way the brain works is far more complex than this simple categorisation.