MEASURING BODIES '5 9
and some people must have longer arms than others. The average
chimp has a longer arm than the average human, but this doesn't
mean that a relatively long-armed human is genetically similar to
apes. Normal variation within a population is a different biological
phenomenon from differences in average values between popula-
tions. This error occurs again and again. It is the basis of Arthur
Jensen's fallacy in asserting that average differences in IQ
between American whites and blacks are largely inherited—see
pp. 186—187. A true atavism is a discontinuous, genetically based, an-
cestral trait—the occasional horse born with functional side toes,
for example.) Among his apish stigmata, Lombroso listed (1887,
pp. 660—661): greater skull thickness, simplicity of cranial sutures,
large jaws, preeminence of the face over the cranium, relatively
long arms, precocious wrinkles, low and narrow forehead, large
ears, absence of baldness, darker skin, greater visual acuity, dimin-
ished sensitivity to pain, and absence of vascular reaction (blush-
ing). At the 1886 International Congress on Criminal Anthro-
pology, he even argued (see Fig. 4.2) that the feet of prostitutes are
often prehensile as in apes (big toe widely separated from others).
For other stigmata, Lombroso descended from the apes to seek
4 • 2 The feet of prostitutes. This figure was presented by L. Jullien to
the 4th International Congress on Criminal Anthropology in 1896. Com-
menting upon it, Lombroso said: "These observations show admirably that
the morphology of the prostitute is more abnormal even than that of the
criminal, especially for atavistic anomalies, because the prehensile foot is
atavistic."