Nearly nine in ten people predominantly use their right hand, a pattern that researchers say may be rooted in major changes during human evolution.
A University of Oxford study published in PLOS Biology suggests that right-handedness developed alongside the expansion of the human brain and the permanent adoption of walking on two legs.
What primates reveal about handedness
Researchers examined 41 individuals from different monkey and ape species, comparing their characteristics with those of modern humans.
Unlike Homo sapiens, most other primates showed no clear preference for using either the right or left hand.
Early hominins, including Ardipithecus and Australopithecus, appear to have shown only a mild preference for the right hand, similar to that observed in great apes today.
Right-handedness became more pronounced in later human species, including Homo ergaster, Homo erectus and Neanderthals, before becoming dominant among modern humans.
How walking on two legs changed the hands
The researchers linked this development to two defining features of human evolution: the growth of the brain and the adoption of permanent bipedalism.
Once human ancestors began walking consistently on two legs, their hands were no longer needed for movement. This allowed them to be used for other activities, including making tools, carrying objects and performing increasingly precise movements.
The study suggests that this created evolutionary pressure for greater accuracy and specialisation in hand movements. As the human brain became larger and more complex, these abilities developed further, eventually contributing to the dominance of the right hand.
The case of Homo floresiensis
Researchers highlighted Homo floresiensis, commonly known as the “Flores Man”, as an important exception.
The species had a smaller brain and showed a much weaker preference for using the right hand. Its anatomy was suited both to walking upright and climbing, which may explain why it did not develop the same degree of hand specialisation as modern humans.
A two-stage evolutionary process
Scientists describe the development of right-handedness as a two-stage process. First, walking on two legs freed the hands from their role in movement. The subsequent development of the brain then supported more complex motor functions and strengthened the preference for the right hand.
Study co-author Professor Thomas Püschel said the findings connect right-handedness with characteristics that distinguish humans from other primates.
By comparing different primate species, researchers can better identify which aspects of human behaviour were inherited from earlier ancestors and which developed during the evolution of the human lineage.
The findings suggest that right-handedness is not simply a biological peculiarity, but the result of a long evolutionary process connected to the development of the brain, tool use and human culture.
Source: vita.gr.
