Around 90% of people worldwide are right-handed. This might seem normal, but it raises an interesting question: why is this trait so common in humans? A new study led by researchers from the University of Oxford is diving into this mystery, linking our right-handedness to early human evolution.
The researchers believe that two key milestones in our evolution—walking upright and having larger brains—helped shape our preference for using the right hand. In their study published in PLOS Biology, they looked at data from 2,025 individuals across 41 species of monkeys and apes. They aimed to test existing theories about handedness, examining factors like tool use, diet, habitat, brain size, and movement patterns.
Initial traits didn’t quite explain why humans are predominantly right-handed. However, when the researchers considered brain size and the balance of arm and leg lengths, the patterns started to make sense. “Our results suggest that our handedness is linked to what makes us human: upright walking and our larger brains,” said Thomas Püschel, lead author of the study.
Historically, as early humans transitioned to walking on two legs, their hands became free for other tasks. This shifted the evolutionary focus toward more specialized hand use. Over time, as our brains grew and reorganized, the right-handed bias became even more pronounced. Evidence shows that early ancestors like Ardipithecus and Australopithecus had a slight right-hand preference, while later species in the Homo genus, including Neanderthals, showed a stronger trend.
Interestingly, Homo floresiensis, a small human species found in Indonesia, displayed a weaker right-handed bias. This could be because they had smaller brains and adapted to both climbing and walking upright.
The study opens the door to more questions. It encourages us to think about how culture might affect handedness and why some left-handed individuals still thrive in predominantly right-handed environments. Recent trends on social media show that left-handedness is celebrated, with hashtags like #LeftyPride gaining popularity.
As we delve deeper into our evolutionary history, understanding our handedness might reveal more about what makes us unique. For those curious about the science behind this study, you can read more in the full piece published in PLOS Biology here.
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Homo sapiens,Human evolution,neanderthals
