Every August 13th, International Left-Handers Day is celebrated. This day celebrates the 10% of the world's population who live in a world designed almost entirely for right-handed people.

Far from just being a matter of preference when writing, using cutlery at the table, or throwing a ball, being left-handed involves a different experience, from the way the brain works to the simplest everyday objects.

How are left-handed people different from right-handed people?

It is estimated that there are about 790 million left-handed people in the world. Being left-handed is not just a matter of motor preference, but also a neurological characteristic.

What happens in the brain of a left-handed person?

The human brain is divided into two hemispheres: the left and the right. Each one controls the motor functions of the opposite side of the body: that is, the right hemisphere handles the actions of the left side, and vice versa. In most right-handed people, the left hemisphere is the most active and usually handles language and logic.

But in left-handed people, the picture is more flexible. Although many also primarily use the left hemisphere for speech or reasoning, a significant percentage lateralize these functions to the right hemisphere or even both hemispheres. The advantage? If one brain area is affected by an injury, having distributed functions can offer greater neurological resilience, reducing the functional impact.

And what do the studies say? Some research points to interesting qualities in left-handed people:

• A 2017 study from the Universities of Liverpool, Milan, and Maastricht found that left-handed people tend to have a greater facility with math, especially in skills such as problem-solving and abstract reasoning.
• On the other hand, a previous study from the University of British Columbia (1995) suggests that those who prefer to use their left hand tend to exhibit divergent thinking, also called lateral thinking. This involves approaching problems from unconventional angles, which is associated with creative and innovative processes.
• A study conducted by experts from the University of Oxford revealed that being right- or left-handed depends on DNA components. "Of the four genetic regions identified, three of them were associated with proteins involved in brain development and structure. In particular, these proteins were related to microtubules, which are part of the internal scaffolding of cells, called the cytoskeleton, which guides the construction and function of cells in the body."

Likewise, left-handed people—having greater functional dominance of the right hemisphere of the brain—are linked to a better ability for visual, spatial, creative, or artistic tasks. This doesn't mean that all left-handed people are artists or misunderstood geniuses, but it does mean that their way of processing information tends to be different.

The curious thing is that, despite their number in the millions, left-handed people still face certain everyday challenges that often go unnoticed. Scissors, can openers, mice, keyboards with the number pad on the right, video game controllers: everything is designed for the majority of right-handed people. Although the offer of adapted products has increased in recent years, it is still common for left-handed people to constantly adapt to a world not built for the way they use their hands.

And if we talk about adapting, there is a historical factor that is impossible to ignore:

For centuries, left-handedness was viewed as a defect. The word "left" in several languages has negative connotations, and until not long ago—the mid-20th century—it was common for left-handed children to be forced to write with their right hand. Even in language, "right" is associated with "correct", while left-handedness carries the weight of myths and superstitions.

Today, fortunately, that panorama has completely changed. There is increasing recognition of the neurological and functional differences between left-handed and right-handed people, and neurodiversity is celebrated as a value. International Left-Handers Day not only seeks to give visibility to those who write with their left hand, but also to challenge those invisible structures that normalize the majority and make differences invisible.