Evidence of Handedness in Homo habilis

Any previous bias against left-handers may date back much earlier in human history that previously believed. This blogger likes the left-handed pitchers of baseball and loves to watch them pitch, but they may have been in the minority as suggested by this posting.

The Smithsonian magazine has again struck “dental cord” when they published an article showing the earliest evidence of right-handedness in the fossil record. Lead investigator David Frayer at the University of Kansas is the author of this investigation titled “Study finds earliest evidence in fossil record for right-handedness.”

The study is published in the Journal of Evolution and reveals striations on the labial surface (occlusal) of Homo habilis that were derived from a cutting motion across the surface of the incisor teeth to detach meaty foods by cutting with sharp stone tools.  The striations are distinct and represent directional marks that indicate right-handedness.

According to David Frayer, handedness and language are controlled by different genetic systems that originate from the left side of the brain.

 

a. Occlusal of Maxillary arch of Homo habilis 1.8 million years. b. Frontal view of the maxilla. c. Labial view of maxillary incisors.

a. Occlusal of Maxillary arch of Homo habilis 1.8 million years.

b. Frontal view of the maxilla.

c. Labial view of maxillary incisors.

Frayer said "that the striations were found only on the labial surface of the incisors and that they veered from left down to the right, indicating right-handedness in Home habilis...an astonishing revelation for dental practitioners who will likely view this research as highly remarkable. The extreme occlusal wear is common in skeletal material of this early age, but the definition of striations on the labial surface might encourage other anthropologists to view more closely the labial features of other anthropologic specimens.

This review taken from "Study finds earliest evidence in fossil record for right-handedness"

Teeth striations of Homo habilis fossil date bace 1.8 million years

Bibliography

Clarke, R.J., Fiore, I., Bondioli, L., Blumenschine, R. J., Perez-Perez, A., Martinez, L.M., Estebaranz, F. 2016 Journal of Human Evolution 100:65-72