A new discovery made by researchers at the University of Kansas could help shed light on how handedness came about in humans, a recent study in the Journal of Human Evolution reports.
Though nine out of every 10 humans are right-handed, most animals have no preference one way or another. Despite the fact that it is a defining human characteristic, researchers know little about how, why, or when it evolved.
To study this, researchers analyzed the remains of a Homo Habilis that lived some 1.8 million years ago in what is now Tanzania. The specimen appears to have been right-handed, making it the earliest discovery of handedness on record. The finding also contradicts previous studies suggesting that the earliest right-hander was a Neanderthal who lived approximately 430,000 years ago.
“This is an exciting paper because it strongly suggests right-handed tool use in early Homo around 1.8 million years ago,” said Debra Guatelli-Steinberg, an anthropologist at the Ohio State University, who was not part of the research, according to Tech Times.
After looking at the remains, the team found abnormal scratches on the teeth that travel from left to right. This pattern suggests an object was dragged down across the teeth from the right side.
A closer look showed that the marks were similar to those on mouthguards used in experiments where people cut meat with their teeth. This suggests it is likely the specimen held the meat in its right hand and then cut it with a sharp tool that cut across the front teeth when it slipped. Both the pattern of the cuts and the way the meat was held point to the Homo Habilis being right-handed.
“Handedness and language are controlled by different genetic systems, but there is a weak relationship between the two because both functions originate on the left side of the brain,” said lead author David Frayer, professor emeritus of anthropology at Kansas University, in a statement. “One specimen does not make an incontrovertible case, but as more research is done and more discoveries are made, we predict that right-handedness, cortical reorganization, and language capacity will be shown to be important components in the origin of our genus.”