Most people are right-handed due to a mix of biology, early brain development, cultural influences, and evolutionary advantages.
According to a report from POPULAR SCIENCE, roughly 85 to 90 percent of people worldwide are right-handed, a pattern consistent across all human populations. Paul Rodway, a senior psychology lecturer at the University of Chester, said no society has ever recorded a higher rate of left-handedness than right-handedness.
Environmental factors influence handedness in some regions, especially in parts of Asia, the Arab world, and Africa, where the left hand is considered “unclean” and children may be forced to switch. “Cultures where there is strong social pressure against left-handedness have lower rates of left-handedness,” Rodway noted.
But biology appears to play a major role. Clyde Francks, a professor of brain imaging genomics, explained that hand preference “is already visible in the movements of unborn fetuses.” Ultrasound scans show most fetuses move their right arm more by the 10th week of gestation and suck their right thumb by the 15th week. Francks added, “It is likely that right-handedness is the default outcome of early brain development as encoded by the genome.”
Researchers believe dozens of genes shape this tendency, while left-handedness may result from random developmental variations. Evolution may also play a part, with advantages in tool use and combat contributing to right-hand dominance, though left-handers retain benefits due to their unpredictability.