Is it true people can be right/left brained?

Roberta Torricelli

According to conventional wisdom, people can be classified as right or left-brained based on their personality, thinking style, or way of doing things. For example, those who are right-brained are supposedly more intuitive and creative, whilst left-brained people are presumably more analytical. None of this is true, the idea that there are right-brained and left-brained people is in fact simply a myth. Although we clearly all have different personalities, there’s no supporting evidence to believe these differences arise from the dominance of one brain hemisphere over the other.

However, it is true that certain brain regions, including the right and left hemispheres, specialize in different kinds of tasks. While the theory of being left or right brained was disproven using functional magnetic resonance (fMRI) studies on alive subjects, the majority of our knowledge regarding specialisation of brain regions and hemispheres derives from “split brain” patients. These are patients that, due to injury or intervention, have lost specific brain regions and along with it, their specialised functions. For example, in 1861 Paul Broca, a surgeon, had a stroke patient who lost the ability to speak and could only communicate using one word. A post-mortem dissection of his brain later revealed a localized lesion in the left frontal lobe. Alike lesions were successively reported in similarly presenting patients, leading to rename this brain region as “Broca’s area”. From there, it was understood that Broca’s area plays a crucial and specialised function in the movement of facial muscles during speech. Furthermore, it was also discovered that for most people, this area is primarily developed in the left hemisphere. This is therefore an example of how different brain regions might hold different specialised functions and how potentially, the right or left-brain hypothesis could have arisen.

However, there is a degree of uncertainty related to this latest example too. Our brains are in fact highly “plastic” structures, which means they can change and adapt to change very well, forming new connections as well as erasing older ones, a phenomenon known as neuroplasticity. This means that when we suffer an injury to a specialised brain region, although we might initially lose the function associated with it, we can train our brain to gain that function back, sometimes to full potential. In this process, another brain region normally not involved in that role, can take over and act as a substitute. Reasonably, this is a rather long process which cannot occur over night, but that can be achieved with regular practice and rehabilitation. Equally, better outcomes can be achieved by keeping a healthy lifestyle and giving the brain time to recover by getting plenty of sleep.

All these findings together have therefore led us to believe that we cannot have right or left-brained individuals, but instead that our brain generally works as a whole, with constant communication running from one hemisphere to the other. It also teaches us that every brain region has the physiological and anatomical basis necessary to perform wide sets of functions although certain ones might appear to be more specialised in some rather than others.