The Left Brain, Right Brain Fallacy

Probably one of the greatest fallacy intriguing human minds is the one about being left/right brain person. Popular beliefs imply that if someone is right handed they have an active “left brain” and vice versa. Or the fact that being left brained makes one more logical with better mathematical skills, and being ‘righty’ is a sign of creativity and a better imagination, mostly seen in artists or writers.
The source of these myths date back to physicians in the 1800s, who observed that minor damages in one particular side of the brain cause a person to lose certain abilities specific to that half.

In 1844, a book titled, Duality of the Mind described the two parts of the brain as independently functional (this theory couldn’t be proven wrong because fMRI (functional magnetic resonance imaging) technology was still a century and a half away). This myth was further corroborated by classic severing surgeries of corpus callosum (fissure connecting the right and left cerebral hemispheres), which created totally unnatural brains, where the two halves could not communicate anymore. And what happened was stupefying: Now the two parts of the brain could actually work independently!

These people could respond differently to stimuli provided to their right and left sides, as they would always get contrasting responses. For instance, when shown a picture to their 'right' field of vision and asked to name it, they were always correct but when it was shown to the left field of vision they could draw the same by their left hand, but could not say it. Mind-blowing!

The Nobel Prize winning scientist Roger Sperry did some of these experiments to find out which parts of the brain had traits more closely related to mathematical abilities, language, etc. But it was popular psychology fanatics who took this idea and stretched it further from reality; the idea of human attributes being determined by dominants halves of the brain started spreading like fire.

It started appearing in books, journals and newspaper editorials. What made it worse were the personality assessment tests, which were designed to tell you whether you’re a right brained/left brained person. Various books started cropping up based on the idea, providing methods to train the weaker halves of your brain. One could not have thrown a dead cat around in the world without hitting a page offering such tests.
What the research actually alluded to was the fact that certain processes are spatially centered to one area of the brain, and disrupting them would cause a loss of that particular function. Now, there are certain functions, which reside more in one part of the brain than the other, like language in the left, and attention resides in the right frontal hemisphere, but that is simply lateralization. It has nothing to do with one part being more dominant than the other.

Brain lateralization has been known for almost 4 decades now and humans are not the only species, which possess it. Fish, reptiles and other mammals are known to have it too. It is known to have some evolutionary advantages then, may be during evolution, organisms with lateralized brain could perform two tasks simultaneously. But, neither one is known to be dominating over the other.

If nothing else, they have functional connections. i.e., almost all the functionally specific regions have connections to the other regions in the brain in ways which are complex yet almost mystical.

For analogy, consider the connections between proteins in a human cell. Each protein is regulated by other proteins (I am sure you know by now that I study protein networks). The computer science geeks can imagine the brain not like a single computer with multiple hardware units, but more similar to gazillion computers connected through infinitely fast (almost 100 m/s) cables.  

Let’s think of a better evidence to support this myth.

It would involve studying the brains of mathematical wizards, analytical thinkers on one side and creative, imaginative people (basically, anyone except politicians and bankers) on the other side. Measuring their brain activity could shed light on the facts that do they on an average use much more of their respective halves? (Some people actually manage quite well to use none). Well, there has been no evidence found yet to support this popular idea (If someone is out there with evidence, now is the time for the real slim shady to stand up!).

In fact, the opposite evidence for this myth has been found in musicians having larger than normal corpus callosum. Hence, learning music does not activate a particular part of the brain, but improves the connectivity between different regions (For those of you who want to know more should see this exhilarating video of live brain imaging of a musician while he is playing an instrument, I call it ‘brain hustle’).

Another landmark study conducted by Utah scientists triumphed in debunking this myth to some extent. They analyzed the brain scans of 1000 individuals and found absolutely no supporting evidence for left/right brain dominance. What they observed was already known, that is the strong lateralization of brain regions like language processing in the left hemisphere, and attention predominantly showed right lateralization. These so called hubs light up when performing a task particular to their functional specification.

Aha! Science: 1, pop-psychology: 0.

Even though the hubs lit up, they nonetheless received input from other areas of the brain. Therefore, everything in the brain is connected to mostly everything else. Sometimes it makes me wonder that how important is the role of technology in promoting the information about brain’s nature. This study would have never been possible without the dawn of fMRI.

And many of us would all be blindly following the myths, pulling our brains out struggling to get a particular half work better.

Interestingly, when one part of the brain fails due to seizures or other conditions, the other available regions take over certain functions. For example blind people being unable to use their visual processing regions, process sound in an enhanced manner, they are also known for processing language. Or the bio hacked guy (yes he is a cyborg) Neil Harbisson who had color blindness, now ‘hears’ all colors through a camera antenna attached to his temple. What is amazing about Harbisson is that he not only perceives visible light, but also infrared and UV light through various combinations of sound waves (and here comes the age of implantable technology to enhance human cognition).

A more enthralling phenomenon is of a functional take over from parts whether damaged or not. Blind people are able to use visual areas to amplify sound processing, like Daniel Kish, an American expert at human echolocation. The regions in his brain, which are usually known to be responsible for visual processing, now light up when he uses echolocation to find his way or make sense of his surroundings (by the way, he can ride a bicycle on a busy road using echolocation).

What can be more counterintuitive? There are several other cases where people have this ‘hustle’ in the brain regions responsible for vision to the sound of approaching footsteps. Of course this was only possible for people who are congenitally blind or lost their sight at an early age, so their brain was virgin enough to make connections with the other regions and had enough time to do so. This is known as neuroplasticity. But after looking at this evidence, it could not be said that one region is genetically hard wired to have only one particular function. 

During my research, I stumbled upon a report of a case defying all medical predictions, wherein a kid, Jake Gladstone was born with nearly half of his brain missing! What the F..k right ? One would expect such a kid to never be able to walk, talk, play or code (yes, that’s what many kids do these days for fun). Moreover, would he always be left brained? No! Jake is like any other 4 year old, running around, talking. Although his language skills are not similar to the kids of his age, and has a dysfunctional right arm. But his skills are slowly improving and he can solve math problems, paint and does everything else like a four-year-old. But it is still amazing to see what his brain achieved at half the size.

Surely now, the dominant half myth should be enclosed in a bag and thrown in a deep ocean. 

However, what would be interesting to know is whether there are chemical differences between the two halves. For instance, if one half has higher distribution levels of a particular neurotransmitter than the other or whether quantities of receptor channels are more on one particular half making it functionally more diverse. It would also be fascinating to know any structural differences in connectivity within the two halves; can one half have more connections within itself? What if the two parts experience emotions differently? Can one half be more dominant in repressing the activity of the other half? We are yet to stumble upon the specific answer to these questions.

Another reason for the prevalence o this particular myth can be its simplicity. But remember however tough it might be, we still have to suppress our beliefs and look at the truth even if it’s more complicated than what meets the eye.

I hope this myth is not more than a tiny hole in our ship whose journey is to decipher how our brains really work, and we seem of have seen only the tip of the iceberg!

So, next time you tell yourself that you weren't good at art as you’re a ‘leftist’ (analytical, logical) then you should look for a more politically correct excuse, for this one may not suffice.

Thanks for Reading.
And remember to always stay curious.