"Why Are 9 Out of 10 People Right-Handed?"...The Reason Revealed

Link to Bipedalism and Brain Development
Repeated Use Changes Bone Density and Muscle Strength

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The specific evolutionary background and scientific causes behind the predominance of right-handedness in humans have been analyzed.

According to the New York Post on May 18 (local time), a research team led by Dr. Thomas A. Püschel at Oxford University recently investigated the evolutionary lineage of a total of 41 primate species.

The study found that, unlike humans, other primate species tended to use both hands relatively equally. In contrast, as humans evolved, the establishment of bipedalism and an increase in brain size led to the development of specific brain regions. As a result, it is analyzed that humans naturally evolved to use their right hand more frequently.

Dr. Püschel explained, "This study shows that human hand preference is closely linked to the key elements of human evolution: bipedalism and brain development."

The researchers stated that hand preference begins in the fetal stage and gradually solidifies through adolescence. They added that repeatedly using a particular hand results in differences in bone density and muscle development.

The human brain exhibits clear division of function depending on which hand is used. The hand that is used more frequently is responsible for precise and fine movements, such as writing or using chopsticks. The opposite hand is specialized for supporting objects or stabilizing posture.

Despite the established tendency for hand dominance, it is known that intentionally using the non-dominant hand can activate "neuroplasticity," forming new neural connections. Practicing daily activities with the unfamiliar hand can temporarily increase activity in the brain regions responsible for movement and balance.

Meanwhile, this study is a macro-level analysis of the evolutionary process of the human species as a whole, and is unrelated to the intelligence or brain size of modern humans. The researchers said, "Why a certain percentage of left-handed individuals still remains is another question that anthropology must address in the future."

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