A new study published in PLOS Biology sheds light on the origins of right-handedness in humans, a trait observed in approximately 90% of the population. Researchers propose that this dominance may have emerged when early human ancestors began walking upright, which allowed their hands to be freed from locomotion tasks. This transition likely contributed to the evolution of larger brains and a preference for using the right hand. The study analyzed data from 2,025 individuals across 41 species of monkeys and apes, testing various hypotheses related to handedness, including tool use and social organization. Findings indicate that early human ancestors like Ardipithecus and Australopithecus may have shown mild right-handed preferences, but the trait became more pronounced in later species of the genus Homo, such as Homo erectus and Neanderthals. The study is significant as it is the first to test multiple theories of handedness within a single framework, providing insights into the evolutionary aspects of this uniquely human trait. Future research aims to explore the cultural factors that stabilize right-handedness and the persistence of left-handedness in human populations.