The second type of evidence is anything that might show an acceleration in
innovation or adaptation, or increasing variety in the technologies used by
different human communities. Unfortunately, early evidence of accelerating
technological change is scarce and ambiguous, particularly from Africa,
where our species probably evolved.
Fossil evidence for most of the last million years is dominated by two other
hominine species, Homo ergaster and Homo neanderthalis. Could they
speak? And could they adapt with the virtuosity of modern humans? We saw
in Lecture Eighteen that ergaster evolved almost 2 million years ago. Some
migrated to Indonesia and China. They probably used ¿ re, and certainly
used “Acheulian” stone tools, which were better made than the “Oldowan”
tools of Homo habilis. This is evidence of technological creativity but not of
exceptional creativity. Other species (including apes such as orangutans) had
migrated from Africa to Asia; evidence on ergaster control of ¿ re remains
limited, and their stone tools barely changed over 1 million years.
Homo neanderthalis seem even closer to us. Neanderthals lived in ice age
Europe and Russia. They were as tall as us and had brains as large as ours
(perhaps even larger). They also manufactured more delicate and precisely
made stone tools described by paleontologists as “Mousterian.” They
probably used ¿ re and hunted large ice age mammals such as mammoth and
woolly bison, which was no small feat!
Yet their technologies show limited variation over 200,000 to 300,000 years,
and there is no proof that they had symbolic language. Indeed, studies of
Neanderthal skulls suggest that their larynx would not have allowed them
to speak like we do. (However, there is somewhat controversial evidence
that Neanderthals buried their dead, which might imply a capacity for
symbolic thought.) Recent analyses of DNA extracted from Neanderthal
skeletons suggest that Neanderthal and human lines split more than
500,000 years ago.
Though tantalizingly close to us, neither ergaster nor Neanderthals display
the technological creativity that is the birthmark of our species. Both species
disappeared about 20,000 to 30,000 years ago, probably under pressure from
Homo sapiens.