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Human Right-Handedness: The Ancient Evolutionary Secret
22 May
Summary
- Brain size and limb proportions influenced handedness in ancient species.
- Right-handedness preference grew stronger with human evolution.
- Early fetuses show hand preference as early as eight weeks.
Scientists are uncovering ancient clues that may finally explain why over 90 percent of humans are right-handed. Studies analyzing hand preferences across numerous primate species, including humans, reveal a significant evolutionary trend.
Our ancestors from millions of years ago showed only a slight preference for right-handedness. However, as brain sizes increased in species like Homo ergaster and Homo erectus, this bias became more pronounced, strengthening as primates evolved closer to modern Homo sapiens.
This shift towards right-handedness is linked to the development of bipedalism, which freed hands for tool use and complex motor skills. The specialization of brain hemispheres also contributed, with different sides managing distinct functions. While the evolutionary path is becoming clearer, the exact reasons for the persistent minority of left-handed individuals remain a mystery.
