What does it mean to have the dominant right or left hemispheres? What does dominance mean here? And what is a hemisphere anyway? Ever heard friends or fellow classmates boast about their excellent art or math skills? Does that have anything to do with right or left hemisphere dominance?
Below, you will find answers to all these questions and more.
A little high school biology
You must have read or heard in biology class that the right side of our brain controls the left side of the body, and vice versa. What this means, in everyday talk, is that when you lift your right leg, write with your right hand or even lift your right arm, it’s the left side of your brain coordinating those movements.
Similarly, if you are using your left limbs for something, it is actually your brain’s right side making those actions possible. These ‘sides’ of the brain are called hemispheres. Keeping this right-hemisphere-left-body rule in mind, a person can either be right hemisphere dominant or left. This whole phenomenon of right and left hemisphere dominance is collectively referred to as brain lateralization.
Right hemisphere dominance:
The right hemisphere of the brain is mainly involved in cognitive functions. They include—but are not limited to— memory, attention, processing visuals, feelings and emotions, and communication. The communication part includes the processing of both literal and implied meanings.
In other words, when you:
- find yourself focusing very hard on a lecture, for instance, or have to force yourself to stop zoning out,
- can differentiate between a visual in 720p and one in 1080p, for instance,
- are aware of when you are feeling sad, as well as identify the cause of that feeling,
- know when someone is really complimenting you or just being sarcastic,
…it is all thanks to your right hemisphere. It is most active in these processes, sparkling and firing up neurons at an intense pace.
Fun fact: Did you know an average human brain contains about 100 billion neurons. Other creatures, such as an octopus, have about 300 billion neurons in their brain! Neurons are the main type of cells in the brain. They are the powerhouses that keep a brain healthy, up and running from birth till death!
Right-hemisphere dominant people mostly go for jobs as artists, writers, or something in drama. Since visual intelligence is associated with the right hemisphere, people dominant in this hemisphere are good at fields involving visual arts.
Personality also differs for right and left hemisphere dominant people. Those that are right hemisphere dominant tend to possess the following personality traits:
- Can easily see and analyze the ‘bigger picture’ in things and situations
- Visualize more, and think less in words
Interesting read: A study in PLoS Biology discovered that the brain’s left hemisphere contains language centers. On the other hand, it showed the right hemisphere to be specialized in nonverbal and emotional communication.
Left hemisphere dominance:
If you are left-hemisphere dominant, you are more likely to be a critical thinker, planner, and organizer. Not arts, but science and maths are your thing. You like to think in words rather than in visuals. A high degree of logic in thinking and behaving is associated with left hemisphere dominance.
For instance, when you:
- Can figure out a way to fit furniture in through a door by creating a blueprint, measuring angles and dimensions here and there,
- Justify your arguments using facts and not emotions,
- Make a study plan and follow organize your schedule according to it,
…it is your left hemisphere in action during all such processes.
Following are some common personality traits of left hemisphere dominant people:
- Critical thinkers (‘thinking outside the box’ attitude)
- Factual, and less emotional
Right-brained/Left-brained – A myth
Like many other scientific findings, the one about right- and left-handers being left- and right-brained, respectively, has also turned out to be a myth.
The differences—such as those mentioned above—between right- and left-brained individuals are known for a fact, yes. There is no myth in that. However, the very ‘strong,’ widely-held belief that lefties are right-brain dominant and righties are left-brain dominant. Now that is something that has proven to not be the case entirely by current research studies.
Did you know: According to Corballis, there are only 10% lefties in the world, 90% are right-handed, and just 1% are ambidextrous (can write with both hands since no hemisphere of their brain is dominant). And it’s all mostly genetic.
What research says
In light of Karlsson’s research on the right- vs left-handed people, left-handers do make use of their left hemispheres, just as it was found that right-handed people use their right hemispheres. Now the extent of that use is what research is focused on. It is no longer fixated on proving that brain lateralization is a myth. For it has already proven long ago that it is.
Attention has been shifted recently to study things like how much of the right hemisphere is made use of by right-handed people for, let’s say, language. Similarly, showing a left-hander’s use of traits generally associated with the left hemisphere is also a common research goal these days.
Handedness and brain lateralization
A band of muscle fibers—namely the corpus callosum— in the middle of the two hemispheres connect them. In simple words, information passing from one hemisphere into the second has to pass the callosum. This is a simple fact related to this muscle fiber band. However, it makes all the difference between a right-handed person being right-brained or not.
It does not matter whether someone is left- or right-handed. That passing of information via corpus callosum always takes place between the two hemispheres. So, suppose a right-handed person is making use of mathematical skills. Skills that the right hemisphere is responsible for.
Will the part of their brain mainly responsible for mathematical skills is not dominant at that very moment? If it is not taking charge and being active, how will that person solve that specific math problem?
Of course the right hemisphere, at that moment, will be the one firing up neurons at an intense pace! Therefore, it is misguided to think that just because someone is right-handed, they cannot be right-brain dominant either.
The two hemispheres are always coordinating. Sure, some things are a specialty of one hemisphere, and other things are not. One hemisphere, therefore, is perfectly capable of taking on certain things all on its own.
Nature thought of everything. It knew that some people will be born lefties and some righties. That is why the corpus callosum exists. So that if someone is right-handed—with their brain’s left hemisphere controlling their body’s right side—they can still make use of their right hemispheres for things the right hemisphere specializes in.
What would we do without the corpus callosum…now that is the right question to ask. Without it, a left-handed person would not be able to process facts (left hemisphere trait) at all. Nor would a right-handed person be able to enjoy the arts or other visuals (right hemisphere trait).
And yet we witness these things happening all around us, all the time, don’t we. That in itself is proof that indeed, a right-handed person can be right-brained, just as a left-handed person can be left-brained.
Fun Fact: According to his research findings, Christopher Ruebeck, PhD, an economist at Lafayette College in Easton, Paris, claims that Left-handed men earn more than women. Furthermore, he reported, “Left-handed men seem to get a higher return on their education.”
Right-handed and right-brained – More than just a possibility
Now that we have established the possibility of the same hemisphere being used for the same handedness, the bigger question arises. The question about whether someone can be ‘dominant’ in the same hemisphere as their handedness.
And the answer is yes, in fact, a screaming yes. For it is more than just possible; it is not that uncommon these days either.
When a right-handed person is left-brained and vice versa, it means their brain is lateralized. The majority of the human population is brain-lateralized. This is also referred to as brain asymmetry. However, a minority of the human population is either symmetrically-brained or ambidextrous.
Asymmetrical vs symmetrical brains
Have you ever come across a person who can write with both hands, perhaps even at the same time? If so, such a person is called ambidextrous. They can perform this seemingly marvellous feat because they are neither right-brained nor left-brained. Their brains, according to scientific terms, are ‘symmetrical’ or exactly alike, in other words. No hemisphere is dominant over the other.
Fun fact: Einstein’s brain was symmetrical!
Symmetrical brains do have a downside, too. There is no passing of information back and forth between the two hemispheres that would exhaust them. However, since the middle passage (corpus callosum) is not that active, it allows certain mental dysfunctions to develop easily in such brains.
On the other hand, right people- or left-brained people are considered to have asymmetrical brains. The dominance of hemispheres in their own respective traits is great. For it allows for localization of functions in that hemisphere, according to research conducted by Michael Corballis, a psychologist at the University of Auckland, New Zealand.
In the light of these scientific findings, a person can be right-handed AND right-brained at the same time. And if they are, that means their brain is symmetrical. That is the good as well as the bad news.
The right hemisphere of the brain controls the body’s left side and vice versa. This is a commonly-known fact today. However, research has disproved the claim that right-handed people are always left-brain dominant and vice versa. In fact, with the latest technological advancements, neuroscientists have successfully shown how right-handed people can, too, be right-brain dominant, just as lefties can be left-brain dominant.
Countless studies conducted on mental dysfunctions and illnesses etc. have brought to light many things that will help even future generations to come. One of those findings has shed light on the importance of the corpus callosum. Some people are right-brained or left-brained, a phenomenon called brain lateralization.
However, some are neither left-brained nor right-brained. And that is what makes it possible for them to be right-handed and right-brained at the same time. There are also ambidextrous people, those who can write with both hands due to the same reason. They don’t have dominance in either hemisphere.
Lack of brain hemisphere dominance comes with its own advantages and disadvantages. But as far as the impossible and possible is concerned, it’s a commonly observed phenomenon, and not just a possibility, for someone to be right-handed and right-brained, too.