https://en.people.cn/n3/2026/0415/c90000-20446712.html

https://www.sciencedirect.com/science/article/pii/S1673852725002954?via%3Dihub

Researchers from the Chinese Academy of Sciences (CAS) have revealed how hand preference develops through animal experiments. The research team found that untrained mice use both paws equally when eating, with no specific preference. In the experiment, the scientists designed a special cage with a small hole placed in a challenging position, so that the mice had to use a specific paw to reach the food inside. After just 5 to 7 forced feeding trials, the mice developed a lasting preference. In a follow-up experiment, scientists forced them to switch. Right-paw habits proved persistent and hard to change, whereas left-paw preferences could be more easily “corrected” to right-paw use. Even when mice were forced to alternate between paws, most ended up favoring their right paw. Only a small minority remained “stubborn” left-paw users, reproducing the real-world distribution of human handedness.

Based on these results, the researchers concluded that human handedness is not innate, but rapidly established during early life through repeated unilateral hand use. A right-hand preference, once formed, is more stable and easier to sustain than a left-hand one, granting it a cumulative advantage in individual development. Reinforced by a right-hand-dominant social environment, this tendency ultimately creates our ‘right-handed world.