Biomedical Engineering Reference
In-Depth Information
necessarily implied about
cultural
recency. This “out-of-Africa” scenario
has received immense coverage in the popular press through its vivid
emblem of an “African Eve,” of course, but also through the clarity and
simplicity of its opposition to the “multiregional” or “regional continu-
ity” hypothesis—according to which the
Homo erectus
populations in
different parts of the world didn't go extinct (as proposed by the mole-
cularists) but gave rise to the distinct (but commingling) populations of
Homo sapiens
that eventually evolved in those regions. The opposing
molecularist, sequence-based recency thesis has become the dominant
view; it has done this partly through the strength of its molecular
methods, but also by successfully tarring the multiregional model
(inspired by Franz Weidenreich) with older polygenist traditions, which
presumed deep and usually invidious racial divisions.
All three of these transformations—archaeological, paleontological,
and genetic—have been important in the rising stock of human recency.
Of course, the factors I have mentioned and will soon elaborate on are
not the only elements at work; there are others—like the triumph of
Stephen Jay Gould and Niles Eldredge's punctuated equilibrium, or
efforts by paleoanthropologists like Richard Klein, who argues that the
explosive growth of human innovativeness circa fifty thousand years
ago—John Pfeiffer's “creative explosion” or Jared Diamond's “great leap
forward”—might be traceable to some sort of “neural mutation.”
9
Recency is not the same as suddenness, however, and the idea of recency
has become at least as popular among anti-Gouldians as Gouldians.
Indeed, it was two
anti
-Gouldian aspects of the thesis that first piqued
my own interest in human recency: (1) the idea that language capacities
might have developed relatively late in human evolution (albeit perhaps
gradually, over a long period of time), and (2) the awkward fact that the
human cultural “Big Bang” seems perilously close to the point of human
racial differentiation and dispersal, raising the specter that some “races”
might actually have become “human” earlier than others—a common
idea among segregationalists and polygenists as late as the 1950s and
1960s.
10
Both of these are rather non-Gouldian concerns, and avoidable;
both, I would say, can be rectified within an expanded theory of recency
consistent with racial egalitarianism and punctuated equilibrium.
Before I turn to these crises, let me make two methodological points
about opportunities for historical inquiry in this area.
