more on complex tools

Glenn R. Morton (grmorton@waymark.net)
Sat, 22 May 1999 16:45:20 -0500

I reported last week that there were some very complex tools discovered
in rocks dated 2.34 Myr ago. I got the Nature report this week and there
are some very interesting items. Steele, the commentator on this
discovery said:
"The archaeological site of Lokalalei 2C, close to the western margin
of Lake Turkana, was excavated in 1997. It is dated to 2.34 +/- 0.05
Myr, and consists of a dense concentration (about 10 m2 in extent) of
2,067 fragments of worked stone, with smaller quantities of rather
degraded animal remains. . . .By fitting the discarded pieces back
together-up to 20 from a single cobble-Roche et al show that these
hominids had a high degree of control over the force, amplitude and
precision of the hand movements required to detach flakes successfully
and repeatedly from the parent core. The knappers may also have
appreciated the mechanical properties of their finer grained raw
materials. No one has previously identified such skill so clearly in
artefacts that are so old." James Steele, ""Stone Legacy of Skilled
Hands,""Nature, 399(1999):24-25, p. 24
**
"Roche and colleagues' findings from Lokalalei 2C unequivocally show a
good command of basic fracture mechanics, as applied to the raw
materials used at this location. Let us not underestimate the
difficulty of learning to execute rapid, precise, aimed movements of the
arm and hand such as those needed for successful stone flaking. Wild
chimpanzees in West African groups with cultural traditions of nut
cracking using unmodified stone hammers take several years to become
fully proficient at opening the nut without crushing its kernel. The
effort is worthwhile: in the nut season, an adult female can obtain
3,800 calories per day this way. Understanding, and exploiding the
fracture mechanics of stone itself to produce flaked stone tools adds a
new level of complexity to such tasks." James Steele, ""Stone Legacy of
Skilled Hands,""Nature, 399(1999):24-25, p. 24

Steele points out that to date the only known candidates for the tool
maker are "robust australopithecines (Paranthropus aethipicus, cranial
capacity of about 410 cm3 ), and the earliest Homo (with affinities to
H. habilis, 500-650 cm3 , and/or H. rudolfensis, 600-800 cm3)"
His article probably went to press prior to the discovery of
Australopithecus garhi (cranial capacity 450 cm^3) who apparently made
tools also at this time. (Berhane Asfaw, et al, "Australopithecus garhi:
A New Species of Early Hominid from Ethiopia," Science,
284(1999):629-635, p. 632; Jean de Heinzelin et al, "Environment and
Behavior of 2.5-Million-Year-Old Bouri Hominids," Science
284(1999):625-629, p.629)

The original report add,

"The repeated application by the knappers of the same technical
principles to a whole series of cores, and during the reduction of each
core, indicates an elaborate debitage scheme, implying motor precision
and coordination. These principles include an appreciation of the
quality of the collected raw materials, a judicious exploitation of the
natural morphology of the blocks and the maintenance of adequate flaking
angles during the entire debitage sequences. These show that the notion
of production was already assimilated by a group of hominids in this
particular area. This notion is integrated within a real debitage
strategy, here well-mastered and unprecedented for this period.
"Overall simplicity and similarities between assemblages are the two
main arguments recently put forward to substantiate a technological
stasis hypothesis between the 2.6 and 1.6 Myr time periods, and to merge
the related assemblages into a single vast 'Oldowan' technocomplex. The
stasis hypothesis cannot hold out against the detailed technological
analysis of the LA2C lithic assemblage. There can be no doubt about the
elaborate character of the LA2C lithic debitage schemes, which are far
more sophisticated than at any other Pliocene site. The assemblage also
provides yet another example of the technical diversity within this time
span. It should be stressed, however, that temporal variation is not
necessarily in the direction of every greater sophistication. Given the
so-far largely underestimated spatio-temporal distance separating
Plio-Pleistocene 'Oldowan' assemblages, the variation observed probably
reflects technical solutions to different environments and needs, as
well as differences in cognitive and motor skills among early hominid
groups characterized by non-synchronous evolutionary processes." H.
Roche, et al, "Early Hominid Stone Tool Production and Technical Skill
2.34 Myr ago in West Turkana, Kenya," Nature, 399(1999):57-60, p. 59

-- 
glenn

Foundation, Fall and Flood Adam, Apes and Anthropology http://www.isource.net/~grmorton/dmd.htm