Short Science: Right-Handedness Has a Long Evolutionary History

A recent study of Homo habilis (“handy man”) shows that right-handedness goes way back. (Also—speaking as a lefty—this may be conclusive evidence against an intelligent designer. Just saying.)

A study of the striations on teeth of a 1.8 MYA H. habilis fossil dating at the University of Kansas, researchers were able to show that the marks run from left to right.

According to the study, the marks were produced when the individual “used a tool with its right hand to cut food it was holding in its mouth while pulling with the left hand. The scratches can be seen with the naked eye, but a microscope was used to determine their alignment and to quantify their angulation.”

While apes are 50-50 in handedness, they note, humans are closer to 90 percent right-handed. The difference is likely in the brain’s structure, according to lead author and anthropologist David Frayer. This says “something further about lateralization of the brain….We already know that Homo habilis had brain lateralization and was more like us than like apes. This extends it to handedness, which is key.”

Read a summary at Science Daily or the full study at Science Direct.

Photo: Homo Habilis by Cicero Moraes (CC BY-SA 3.0).