Such a change would lead to a more consistent adoption of the
upright attitude, which is partly found in the anthropoid apes,
especially the gibbons. The fore limb would be no longer a
support of the body; the hand would be used more for grasping;
and the hand-centre in the brain would be proportionately
stimulated. The adoption of the erect attitude would further lead
to a special development of the muscles of the head and face, the
centre for which is in the same important region in the cortex.
There would also be a direct stimulation of the brain, as, having
neither weapons nor speed, the animal would rely all the more on
sight and mind. If we further suppose that this primitive being
extended the range of his hunting, from insects and small or dead
birds to small land-animals, the stimulation would be all the
greater. In a word, the very fact of a change from the trees to
the ground suggests a line of brain-development which may
plausibly be conceived, in the course of a million years, to
evolve an Ape-Man out of a man-like ape. And we are not
introducing any imaginary factor in this view of human origins.
The problem of the evolution of man is often approached in a
frame of mind not far removed from that of the educated, but
inexpert, European who stands before the lowly figure of the
chimpanzee, and wonders by what miracle the gulf between it and
himself was bridged.
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