A significant majority of humans, about 90%, are right-handed, a phenomenon that has intrigued scientists for years. A recent study led by researchers at the University of Oxford provides insights into this trait, linking it to two major evolutionary milestones: the transition to upright walking and the expansion of brain size. The study analyzed behavioral data from 2025 monkeys and apes across 41 primate species, revealing that humans initially stood out due to their pronounced right-hand dominance. However, when factors like brain size and limb proportions were considered, humans were no longer seen as an anomaly. The research indicates that early hominins had a slight right-hand preference, similar to modern great apes, but this changed with the emergence of the genus Homo. Species such as Homo erectus and Neanderthals exhibited a stronger right-hand preference over time. This evolution of handedness appears to follow a two-stage process: first, the shift to upright walking allowed hands to be used for specialized tasks, and second, the growth of the human brain further reinforced this specialization, leading to the strong right-hand dominance observed today.