Debunking the Left Brain Right Brain Myth

You’re probably aware that about 90% of people are right-handed.  Much of the reason behind this is genetic. It remains a bit of a mystery as to why our genetic evolution led to so many more people who are right-handed than those who are left handed. But for certain tasks, this handedness can be overcome.  For example, right handed people can learn to play tennis, golf, or play a guitar and become successful by using their other hand. It may be more a matter of how they’re taught and what gets reinforced than about a hardwired preference for one hand or the other.

You’ve probably come across the idea that people are either left-brained or right-brained, and this drives their thinking.  From books to television programs, you’ve probably heard the phrase mentioned a number of times, or perhaps you’ve even taken an online test to determine which side of the brain you mainly use.

The brain contains two hemispheres that each perform a number of different roles.  The two sides of the brain communicate with each other via the corpus callosum, the structure that connects the two hemispheres of the brain.  The left hemisphere controls the muscles on the right side of the body, whilst the right hemisphere controls those on the left.  This is why damage to the left side of the brain might have an effect on the right side of the body.  Generally speaking, the left side of the brain tends to control many aspects of language and logic.  While the right side of the brain tends to handle spatial information and visual comprehension.

The left brain-right brain theory suggests that different cognitive functions are localised in either the left or right hemisphere.  The original idea implies that certain functions are exclusively controlled by one hemisphere, the left side controlling logical, detail-orientated, rational thinking to provide analysis and objectivity, and the right side controlling creative, intuitive, free thinking to provide description and subjectivity. In reality, most cognitive functions involve both hemispheres working together.

Whilst this idea has been popular in the past and remains popular with a lot of business people who don’t keep up to date with changes in thinking around neuroscience, it’s been proven on many occasions to be over simplistic and inaccurate.  Whilst there is some evidence of lateralisation for specific functions, as we’ve seen, such as language processing being more prominent in the left hemisphere, the basic idea over generalises brain function, fails to account for individual variability and plasticity, and doesn’t align with current neuroscientific research.

There’s also the issue of cultural bias with this theory, as it tends to oversimplify the complex interplay of culture, genetics, and individual experiences in determining cognitive abilities and personality traits. Research has shown that abilities in subjects such as maths and music are strongest when both halves of the brain work together.

Like many popular psychological myths, the idea that people are left-brained or right-brained grew out of observations of the human brain that were then dramatically distorted and exaggerated.  Today, neuroscientists know that the two sides of the brain collaborate to perform a broad variety of tasks through communication via the corpus callosum.  Our understanding of brain function has developed to recognise the complex interactions between both hemispheres and distributed neural networks in performing cognitive tasks. Advanced neuroimaging techniques such as functional Magnetic Resonance Imaging, fMRI, and Diffusion Tensor Imaging, DTI, have shown that cognitive functions are not so strictly lateralised.  Many cognitive tasks require the integration of both hemispheres.  Tasks that involve creativity and problem-solving often draw on the combined resources of both hemispheres at the same time.  The brain is highly adaptable and capable of reorganising itself after injuries or during learning processes.  This plasticity means that functions can be reassigned to different areas of the brain in both hemispheres. Also, there is considerable variability among people in terms of where these functions are assigned in the brain, and these can change over time due to factors such as learning, ageing, or injury.

A better way of working with the ideas that stem from this thinking is to measure and assess people’s favourite focus based on their preferences within a work-based context.  These can be accurately assessed using valid behavioural inventories such as disc and social interaction styles based on sound scientific research. Using these within a team development intervention can highlight useful differences in people’s preferred ways of working.  These interventions can help people to understand and support each other and to emphasise key strengths and liabilities, rather than dismissively characterising people into one of two groups based on outdated, inaccurate beliefs.

While the idea of right brain and left brain thinkers has been widely dismissed, its popularity persists.  The idea seems to have taken on a mind of its own within popular culture, from magazine articles to books to games to online quizzes.  You’re probably bound to see information suggesting that you can improve the power of your mind if you just discover which side of your brain is stronger or more dominant.  The important thing to remember is that these things are entirely for fun, and you shouldn’t take your results too seriously.