Archaeological records ― paintings,

Archaeological records ― paintings, drawings, and carvings of humans engaged in
activities involving the use of hands ― indicate that humans have been predominantly
right-handed for more than 5,000 years. In ancient Egyptian artwork, for example, the
right-hand is depicted as the dominant one in about 90percent of the examples. Fracture
or wear patterns on tools also indicate that a majority of ancient people were right-handed.
Cro-Magnon cave paintings some 27,000years old commonly show outlines of human
hands made by placing one hand against the cave wall and applying paint with the
other. Children today make similar outlines of their hands with crayons on paper. With
few exceptions, left hands of Cro-Magnons are displayed on cave walls, indicating that
(10) the paintings were usually done by right-handers.
Anthropological evidence pushes the record of handedness in early human ancestors
back to at least 1.4 million years ago. One important line of evidence comes from
flaking patterns of stone cores used in toolmaking: implements flaked with a
clockwise motion (indicating a right-handed toolmaker) can be distinguished from
(15) those flaked with a counter-clockwise rotation (indicating a left-handed toolmaker).
Even scratches found on fossil human teeth offer clues. Ancient humans are thought
to have cut meat into strips by holding it between their teeth and slicing it with stone
knives, as do the present-day Inuit. Occasionally the knives slip and leave scratches on
the users' teeth. Scratches made with a left-to-right stroke direction (by right-handers)
(20) are more common than scratches in the opposite direction (made by left-handers).
Still other evidence comes from cranial morphology: scientists think that physical
differences between the right and left sides of the interior of the skull indicate subtle
physical differences between the two sides of the brain. The variation between the
hemispheres corresponds to which side of the body is used to perform specific
(25) activities. Such studies, as well as studies of tool use, indicate that right- or left-sided
dominance is not exclusive to modern Homo sapiens. Populations of Neanderthals,
such as Homo erectus and Homo habilis, seem to have been predominantly
right-handed, as we are