Can you boost your brain power by making yourself ambidextrous?

Could learning to write with both hands make your brain sharper and more speedy? Could training schoolchildren to use their non-dominant hands improve their exam results? Such claims have been popular for more than a century.

Handedness – the preference for using one hand over another – is one of the deepest mysteries of neuroscience. We still know very little about what being left- or right-handed means for brain function, or about what effects learning to become ambidextrous might have.

By the time we reach age four, we have developed a preference for using one hand over the other, which remains with us for the rest of our lives. The vast majority of us favour the right hand, and most of the rest prefer the left. But a tiny minority – fewer than one in 100 – are ambidextrous. This handedness is inborn and at least partly controlled by genetics. It is also seen in other animals, including some primate groups. But the reasons why there is an almost universal preference for the right hand are still unclear.

Two-handed, two-brained?

We do know that handedness is related to asymmetries in brain function: the left hemisphere of the brain controls the right side of the body, and vice versa. For most of us, it also contains the brain’s language centres, and so is often said to be dominant over the right.

Historically, left-handers were stigmatised, punished and forced to use their right hand, but the late 19th century saw the emergence of a movement that advocated the benefits of ambidexterity. In 1903, John Jackson, the headteacher of a grammar school in Belfast, founded the Ambidextral Culture Society. Jackson and his followers believed that the brain’s hemispheres are distinct and independent, and that the preponderance of right-handedness was effectively wasting half of our potential to learn.

With ambidexterity training, Jackson wrote, “each hand shall be absolutely independent of the other in the production of any kind of work whatever… if required, one hand shall be writing an original letter, and the other shall be playing the piano, with no diminution of the power of concentration.” Widespread adoption of ambidexterity would, therefore, lead to “a brave new world of two-handed, two-brained citizens”.

Although based on scientific observations, Jackson’s claims were widely dismissed. Nevertheless, a similar school of thought still exists today, and some believe that learning to use one’s non-dominant hand can improve overall brain function. People who make such claims usually invoke the concept of neuroplasticity, a term used to describe how the brain’s structure and function can change in response to experience.

False claims

Take, for example, Whole Brain Power Consulting – “a revolutionary new brain training program,” developed by Michael Lavery, a self-proclaimed “pioneer in the field of applied neuroscience and brain function”. Through a set of “simple ambidextrous skill training, penmanship drills and memory drills,” it promises “to supercharge your mental circuits to boost your memory, beat stress, sharpen your thinking, lift your mood, sleep better and much much more”. All for a one-off payment of just $67 (£50).

Numerous websites further suggest that training yourself to use your non-dominant hand can “unleash creativity.” On his Good Financial Cents blog, certified financial planner Jeff Rose claims that using the “opposite” hand to perform daily tasks such as brushing your teeth “will strengthen neural connections in your brain, and even grow new ones”. It will also, he says, “help you grow brain cells.”

Rose goes on to explain that “the non-dominant hand is actually linked to the non-dominant hemisphere in your brain – the one that isn’t exercised as often… [so] when you use the non-dominant hand, both hemispheres are activated, which may result in thinking differently and becoming more creative.”

While it is true that brain structure and function can be dramatically altered by new experiences and various kinds of training, and that your brain continues to generate small numbers of new cells throughout life, the question of how ambidexterity training affects brain function is still largely unexplored. There is no scientific evidence to suggest that training to use the non-dominant hand confers such benefits.

And while Rose rightly states that the non-dominant hand is linked to the “non-dominant” hemisphere of the brain, his assertion that the non-dominant hemisphere “isn’t exercised as often” is incorrect, because all behaviours, even those that engage brain areas found on only one side of the brain, tend to involve the co-ordinated activity of both hemispheres.

Risk and reward

Some neuroscientists argue that ambidexterity training may actually be detrimental, on the basis of several studies suggesting that natural ambidexterity is linked to poorer academic performance and mental health. These studies show that ambidextrous people perform more poorly than both left- and right-handers on various cognitive tasks, particularly those that involve arithmetic, memory retrieval, and logical reasoning, and that being ambidextrous is also associated with language difficulties and ADHD-like symptoms. Ambidexterity is also associated with greater age-related decline in brain volume.

“The two hemispheres of the brain are not interchangeable,” says cognitive scientist Michael Corballis, of the University of Auckland, who led several of the studies into ambidexterity and academic performance. “These asymmetries probably evolved to allow the two sides of the brain to specialise. To attempt to undo or tamper with this efficient set-up may invite psychological problems.”

This is, however, speculation, and there is as yet no evidence that ambidexterity training causes psychological problems. On one hand, the science suggests that being born ambidextrous may come with slight disadvantages, not only for cognitive functioning, but also for mental health. On the other, it is not at all clear that ambidexterity training would have the same effects on the brain as being born ambidextrous apparently does.

And so, to the question of how learning to use one’s non-dominant hand might affect brain function, there is no easy answer.

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