right-handedness preference – A new study in PLOS Biology links humanity’s strong right-handed preference to upright walking and enlarged brains, arguing the pattern is too widespread to be explained by culture alone.
When a team of researchers published new findings about why most people favor the right hand, they did not start with habits or schooling. They started with how humans move.
In a paper published in PLOS Biology on April 27, researchers argue that two traits uniquely central to being human—bipedalism and enlarged brains—may help explain why right-handedness is nearly universal across cultures, and why no left-dominant human society has ever been documented.
The findings come with a built-in tension: handedness looks personal, but the question is evolutionary. The study, authored by Dr. Thomas A. Püschel and Rachel M. Hurwitz at Oxford’s School of Anthropology and Museum Ethnography. along with Professor Chris Venditti at the University of Reading. is framed around a simple reality the authors say is hard to dismiss—right-handedness is a “robust cross-cultural phenomenon. ” and culture alone seems unlikely to account for how the preference took hold.
Dr. Püschel and his co-authors point to a conclusion that challenges a straightforward story about upbringing: “the predominance of right-handedness in humans is a robust cross-cultural phenomenon. and no left-dominant human society has been documented. making it unlikely that culture alone can account for the evolutionary trajectory of handedness in our species.”.
To get there, the research team collected data from 2,025 individuals across 41 species of monkeys and apes. They then accounted for evolutionary relationships among those species, analyzing how handedness evolved under multiple hypotheses. The variables included tool use, diet, habitat, body mass, social organization, brain size and locomotion.
The authors said their approach was unusually broad for the specific question they were asking. “This is the first study to test several of the major hypotheses for human handedness in a single framework. ” Püschel said in a statement. “By looking across many primate species. we can begin to understand which aspects of handedness are ancient and shared. and which are uniquely human.”.
The results, according to the paper, do not fit neatly into the patterns that helped explain handedness in other species. In the human case, the researchers argue, key steps in our evolution appear to matter in a way that the other hypotheses alone do not.
Their central idea traces right-handedness back to the moment upright walking changed the rest of the body’s options. In the study. the researchers write that when evolution gave humans an upright gait. it freed the upper limbs. creating new opportunities for tool use. gestural communication. and other fine motor behaviors where lateralization could deliver performance advantages.
In that telling. bipedalism is not just a feature of human movement—it is the starting point that allowed handedness to become useful. and then sharpened over time. As larger brains grew and reorganized alongside these new behaviors. the paper says the rightward bias that many people show today became more likely to stick.
The researchers write: “In humans, the evolution of bipedalism and the subsequent freeing of the hands may have intensified selective pressures for stronger hand preferences.”
The team’s study also opens additional threads they say the research now makes possible. They highlight questions about how culture has played a role in normalizing right-hand dominance. why some people remain left-handed. and whether limb preference patterns seen in other species “point to a deeper. convergent story across the wider animal kingdom.”.
For now. the main takeaway is an uncomfortable one for anyone who thinks handedness is mostly about learning: the pattern is so widespread. and so consistent across human societies. that the authors argue the most plausible explanation runs deeper than tradition or habit. The right hand may be favored not because people are taught to use it. but because our bodies and brains evolved in ways that made a strong bias advantageous—and durable.
right-handedness bipedalism enlarged brains PLOS Biology April 27 study evolutionary biology primates Oxford anthropology University of Reading lateralization