The oldowan reassessed: A close look at early stone artifacts

Journal

of Archaeological

Science

1985,12,101-120

The Oldowan Reassessed: A Close Look at Early Stone Artifacts Nicholas Toth” (Received 17 February 1984, accepted 28 September 1984) Early Stone Age assemblagescalled “Oldowan” and early “Developed Oldowan” are discussed,based on the results of a long-term study of Plio-Pleistocene sites at Koobi Fora, Kenya and an extensive experimental researchprogram of replicating and using early stone artifact forms. Five major conclusions are drawn from this investigation: (1) many Oldowan core forms (“core-tools”) are,probably simple by-products of flake manufacture rather than representations of stylistic norms; (2) flakes and retouched flakes-were essential tools in Oldowan technology, particularly for activities involving cutting; (3) this simple technology does not necessarilyreflect the cognitive abilities of the early hominids that manufactured the stone artifacts; (4) there is evidence to show that Oldowan technology can be viewed as a simple curated one, in which raw material was intentionally carried from place to place for future use; (5) early hominid populations that made and used stone implements were not necessarilydependent upon them for their survival. HOMINID EVOLUTION, STONE TECHNOLOGY, LOWER PALAEOLITHIC, COGNITION, OLDOWAN, STONE TOOL TYPOLOGY.

Keywords:

Introduction

It seems certain that the development of technology, along with a suite of other behavioral and biological adaptations, was critical in the success of the genus Homo over the last 2 million years. Flaked stone artifacts are the earliest definite signs of modification of natural materials for use as tools, and suggest a much more complicated technological repertoire than has been observed in modern non-human primates. It is crucial to our understanding of early hominid origins that we explore the adaptive role these stone technologies played, and that we search for any other clues these lithic assemblages may yield concerning proto-human behavioral patterns. This paper is concerned with very early stone artifact assemblages that first appear in the prehistoric record over 2 million years ago (Isaac, 1982) and pre-date assemblages characterized by large bifacial forms (“picks”, “handaxes”, “cleavers”) considered to be the hallmark of the “Acheulean” techno-complex, which emerges in Africa approximately 1.5 million years ago (Isaac, 1982). These earliest assemblages have been classified in various ways in different regions: terms such as “Oldowan” and “Developed “Department of Anthropology, California California

94720 94709,

and Institute U.S.A.

University of Human

of California at Berkeley, Origins, 2453 Ridge Road,

Berkeley, Berkeley,

101 030M4O3/85/020101+20

%03.00/O

0 1985 Academic

Press Inc. (London)

Limited

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Oldowan A” at Olduvai Gorge, Tanzania (Leakey, 1971), and “KBS” and “Karari” at Koobi Fora, Kenya (Isaac & Harris, 1978) have been applied to some local occurrences of pre-Acheulean industries in Africa. Often these pre-Acheulean industries are generically referred to as part of the “Oldowan Industrial Complex” (Isaac, 1984), a convention which will be followed here. While there are certainly some technological and typological changes that occur through time as at Olduvai Gorge (Leakey, 1971), all of these assemblages are usually characterized by simple cores, retouched flakes, unretouched flakes and flake fragments (“d&rage”), and battered stones. Clark (1971). has referred to this technological stage as a “Mode I” industry. Several sites believed to be over l-5 million years old are generally regarded as a part of this technological mode.

(b)

0

5cm

Figure 1. A range of Oldowan forms and their traditional classificatory designations. (a) Hammerstone, (b) subspheroid, (c) bifacial chopper, (d) polyhedron, (e) discoid, (f) flake scraper, (g) flake, (h) core scraper. (Parts (cHh) after Barbara Isaac). Drawn by J. Ogden.

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East Africa: Gona (Hadar), Ethiopia (Corvinus, 1976: Corvinus 8z Roche, 1976, 1980; Roche & Tiercelin, 1977, 1980; Harris, 1983); Omo, Ethiopia (Merrick & Merrick, 1976; Chevaillon, 1976); Gadeb, Ethiopia (Clark & Kurashina, 1979); Melka Kunture, Ethiopia (Chevaillon, 1971; Chevaillon et al., 1979); Koobi Fora, Kenya (Isaac & Harris, 1978); Chesowanja, Kenya (Harris & Bishop, 1976; Gowlett et al., 1981); Olduvai Gorge, Tanzania (Leakey, 1971, 1975); Laetoli, Tanzania (Harris, 1980). North Africa: the Morrocan coastal sequence (STIC quarry, Sidi Abderaman quarry) (Biberson, 1961); Ain Hanech, Tunisia (Biberson, 1961). South Africa: Sterkfontein and Swartkrans (Brain, 1981). Broadly contemporaneous hominids include robust australopithecines (usually designated Australopithecus boisei in East Africa and Australopithecus robustus in South Africa), Homo habilis and Homo erectus. The robust australopithecine lineage first appeared before 2 million years ago and seems to have become extinct by 1 million years ago (Howell, 1978), while Homo habilis first appeared about 2 million years ago, and probably evolved into Homo erectus about 1.5 million years ago (Howell, 1978). It is generally assumed that fossil forms attributed to the genus Homo were the principal tool-makers responsible for archaeological sites. Archaeological sites that appear to Omo River

%

Lake

Figure 2. Map showing the Koobi Fora study area, with the location of the early archaeological sites that were analysed. The sites were numbered in order of their discovery. Site FxJj 63 is an early Acheulean site of uncertain age, and is not included in this discussion. Experimental workshop locations are shown with the symbol “w”.

104

N. TOTH Eroslon surface

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Figure 3. Generalized stratigraphic section at Koobi Fora. The Oldowan rences (FxJj 1,3, 10, 50, 18GL and 33) are found in the Lower and Upper bers of the Koobi Fora Formation.

occurMem-

pre-date the earliest known Homo fossils are relatively rare, and when tools first become fairly common in the record, fossils of larger-brained forms attributed to Homo generally occur at the same localities (e.g. Koobi Fora, Olduvai, Sterkfontein, Swartkrans). Whether the robust australopithecines contemporaneous with early forms of Homo made or used stone tools (perhaps emulating their larger-brained “cousins”) is still unresolved. The most widely used classificatory system for such assemblages was developed by Mary Leakey in her analysis of the early palaeolithic sites at Olduvai Gorge (Leakey, 1971), and is based on the morphology of the cores and retouched flakes (“tools”) found at these sites. Here categories include “choppers”, “polyhedrons”, “discoids”, “heavy-duty scrapers”, “subspheroids”, “spheroids”, “protobifaces”, and a range of retouched forms such as “light-duty scrapers”, “ burins” (rare), and “awls” (rare). Some of these forms are shown in Figure 1. This paper will assess the behavioral implications of such early stone technologies based on a long-term study of Plio-Pleistocene occurrences at Koobi Fora, Kenya (see Figure 2) (Isaac & Harris, 1978). These sites have been radiometrically dated to between 1.9 and 1.5 million years ago (Figure 3). These assessments have been based upon an extensive experimental program of manufacturing and using early stone artifact forms, and analysis of excavated lithic assemblages in light of the experimental results. Methods My study was designed as a holistic approach to early lithic technology, considering the acquisition of raw materials, curation and transport, artifact manufacture, use, possible rejuvenation, discard, and final incorporation of stone artifacts into the geological record. The principal goal of this study was to learn as much as possible about early hominid behavior from the stone artifacts that these proto-humans left behind.

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A more detailed exposition of the methodology and the basic data of this study is presented in Toth (1982). A summary of the analytical procedures employed follows. Studies of raw material acquisition Ancient river gravels at Koobi Fora contemporaneous with the early archaeological sites were analysed to identify the types of raw materials available to hominids and how the palaeogeographic locations of the gravels related to archaeological occurrences. Quantitative information on cobble size and shape was compiled and analysed. (The principal rock type at all Koobi Fora sites was basalt lava, though smaller amounts of ignimbrite, chert and quartz were also used). Modern river gravels at Koobi Fora were also analysed in terms of lithology, size, and shape, for comparison with fossil gravels. All of the rock types used in prehistoric times at Koobi Fora are available in modem channel beds today. Replicative and functional experiments (discussed below) were conducted to discern the mechanical properties and functional capabilities of the various rock types. Studies of artifact manufacture All stone artifacts from excavated Koobi Fora sites were examined for technological features in order to discern patterns of manufacture and reconstruct the reduction of lithic material. Conjoining studies by the Koobi Fora research team successfully refitted numerous stages of flaking from some sites, which provided additional technological information. Several thousand experiments were conducted replicating characteristic Koobi Fora stone artifact forms to determine which techniques and methods were most effective and appropriate for producing the prehistoric forms. Observations were also made of novice stone-knappers with no formal training in lithic analysis or typological systems with special regard to their knapping strategies and resultant artifact forms. Based upon the analysis of the Koobi Fora materials and the results of the experimental replicative program, 29 different ways of reducing cobbles and flakes into characteristic Koobi Fora cores and retouched flakes were identified (called “reduction modes”) (Toth, 1982). These reduction modes were defined on the basis of: (1) the type of blank (“initial form”) being reduced (cobble, all cortical flake, half-cortical flake, non-cortical flake); (2) the flaking pattern (unifacial, bifacial, polyfacial); and (3) the extent of flaking (partial circumference, total circumference). Experiments were performed to determine what patterns of dkbitage (especially whole flakes) were produced by each reduction mode. For each Koobi Fora archaeological site, the excavated cores and retouched pieces were assigned as closely as possible to their appropriate reduction mode. Comparisons were made between archaeological (excavated) populations of flakes and computer simulations of predicted (experimental flake populations which should be represented at each site if all of the stages of core reduction had taken place at the site location. For one site, FxJjSO, all cores and retouched pieces were replicated blow-by-blow to produce an almost identical facsimile, and the experimental and archaeological flake populations then compared (Bunn et al., 1980). Functional studies A wide range of replicated Koobi Fara stone artifact forms (as well as tools of more perishable materials) were used for a wide variety of activities in order to gain a better understanding of which artifact forms were most appropriate for particular functions. Experiments included animal butchery (of goats, sheep, pigs, cows, wildebeest, horses,

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and elephants), bone-breaking, hide working, woodworking, grass cutting, digging, and nut-cracking. Contextual information from archaeological sites was considered for direct evidence of tool use. Lines of evidence included micro-wear traces on stone artifacts (Keeley & Toth, 1981) and patterns of bone modification from Koobi Fora sites (Bunn, 1981, 1982). Taphonomic studies

Based on the experimental study of archaeological site formation by Schick (1984; computer simulations were conducted to see how assemblage composition at Early Stone Age sites would be affected by different hydrological forces before final burial and incorporation in the geological record. The results of my study suggest a need to rethink some common assumptions about the nature of these early stone technologies. These conceptions (or misconceptions) about the earliest archaeological traces will be discussed below. Cores as Stylistic Norms? One prevalent assumption in studies of early stone tools is that the morphological forms called “types” were functionally significant norms that represent target forms or “mental templates” (as defined by Deetz, 1967) of their hominid makers. In other words, an early hominid would, with premeditation, .set out to make a “bifacial chopper” or a “polyhedron” by selecting the proper piece of rock and reducing it in a predetermined manner. Based on my experimental replication of thousands of Oldowan cores and retouched pieces, as well as observations of novice stone-knappers working cobbles (African Initial

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Figure 4. Starting points (blanks or “initial forms”) for producing a range of Oldowan and early Acheulean forms. The terms used to describe cobble shapes are qualitative.

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assistants and Berkeley students), I would argue that much of the variety in form that one observes among Oldowan cores can be produced as by-products of flake production (or as technological “paths of least resistance”) (Toth, 1982: 147,328). Figure 4 shows a range of raw material forms used as blanks (“initial forms”) for manufacturing Koobi Fora cores and retouched pieces. Depending on rock type, blank size, and blank shape, the knappers could produce a wide range of morphological end products, including most of the Oldowan core forms or “types” (Figure 5). Certain forms, such as retouched flakes (“light duty scrapers” or “flake scrapers”) and some of the small “discoids’ certainly do appear to have been made for use, since the tiny flakes removed would not have been very useful. But I have replicated many of the other Oldowan “core tool” forms, including “choppers”, “polyhedrons”, larger “discoids”, and “heavy-duty scrapers” (“core scrapers”) without premeditation during experimentations in the production of flakes from a variety of initial forms. An interesting pattern emerges when one examines the relationshin between artifact size and palaeogeographic location at Koobi Fora (Isaac, 197f .L. Isa& & Harris, 1978: Harris, 1978; Harris & Isaac 1980; Toth, 1982). Figure 6 hows tiI e relationship b&w een

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Figure 5. Chart showing the relationships between the initial form and probable end products for Oldowan and early Acheulean forms. Many core forms, such as “choppers”, “discoids”, “polyhedrons” and “core scrapers” can be produced without premeditation during the process of flake production, and in fact these forms can often grade into one another during reduction.

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Distonce

from

basin morgin

(km)

Figure 6. Diagram showing the relationship between artifact size and distance from the volcanic highlands (the basin margin, or interface between the sedimentary basin and the volcanics.) The maximum dimensions of the largest cores (m-m), flakes (V---V), and unflaked clasts (0 .. . 0) from each site are plotted against the estimated distance of the sites from the basic margin. Note the general decrease in size of lithic material away from the basin margin, in the direction of the proto-Lake Turkana.

the maximum artifact size and maximum unflaked clast size at Koobi Fora sites and the distance between the sites and the margin of the sedimentary basin (where the artifactbearing beds contact the volcanic high!ands). There is a general decrease in the size of artifacts and unflaked material at sites as one moves away from the volcanics towards the proto-lake Turkana to the west. This is primarily because stream gradients and carrying capacity decreased away from the highlands. Sites FxJj 1, 3, and 10, in the Lower Member of the Koobi Fora Formation, and dated to approximately 1.9 million years ago, are further away from the volcanics, and are found in low-energy sedimentary regimes. At these sites, hominids must have transported artifacts over minimal distances of several kilometers (Isaac, 1976). This implies that sites nearer the volcanics would have had larger sizes of locally available lava clasts to flake, which can have technological and typological repercussions upon an artifact assemblages. My replication experiments indicate that a wider range of morphological core forms is to be expected if larger sizes of raw material are used (Toth, 1982: 141-142). Larger cobbles can usually be flaked more intensively and can potentially produce a wider variety of final core morphologies (“types”). While other factors such as activity variation or sedimentary context may also have their effect upon intersite assemblage variability (Harris, 1978) much of the observed range of variation in core forms could be, to a large extent, due to variation in the size of the available raw material. The type of available raw material as well as the size is obviously going to have a great effect on the range of artifact forms possible. Two examples show this relationship well.

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In the Omo Valley, southern Ethiopia (Met-rick & Merrick, 1976), the only apparent raw material available in many areas consisted of small quartz pebbles. As a result, the range of forms from relevant archaeological sites consist simply of sharp quartz fragments produced by flaking or smashing small quartz clasts (probably with some sort of bipolar technique). The size and the non-isotropic nature of the quartz pebbles would severely limit the range of possible artifact forms produced. The second example concerns the presence of “subspheroids” or “spheroids” only at some Oldowan sites. At Koobi Fora the principal raw material is basalt lava, and there is an almost total lack of spheroids or subspheroids. At Olduvai, where larger pieces of quartz and quartzite were available, spheroids and subspheroids are much more common. It seems likely that raw material availability is to a great extent responsible for this aspect of assemblage variability between the two regions. The Olduvai forms perhaps reflect heavy battering as wellcurated hammerstones, food processors, or (to me, less believably) missiles. Investigations by Willoughby (198 1), should shed light on this problem. Based on my experimental work, it seems likely that much of the variation in Oldowan technology often attributed to stylistic norms is in fact the end product of a lithic reduction designed to produce sharp flakes, and that many of these core forms may actually be “waste”. The question of the functions of Oldowan artifacts will be discussed below. Oldowan Cores as the Principal Tools? Another popular conception is that Leakey’s Oldowan “tool types”-her cores and retouched piece-were deliberately designed for use. While it is generally acknowledged in palaeolithic studies that some of the dPbituge (flakes and fragments) found at sites may have been used as tools, in discussions of Oldowan technology the primary emphasis has generally been upon the “core tools”. Also, most reconstructions of early hominids show them using chopper-like artifacts rather than flakes for a range of activities. I have experimentally replicated thousands of Oldowan artifact forms using the same raw materials as Oldowan knappers and have used these for a wide range of functional experiments (Toth, 1982: 288-324). These experiments indicate that flakes are especially critical for butchering animal carcasses, since a sharp edge is essential for initial slitting of the skin. A flake or a sharp retouched flake edge is also best for meat cutting (Acheulean handaxes and cleavers with sharp edges are also excellent meat cutting tools). As a result, I suggest that simple flakes and fragments were probably at least as important as Oldowan cores for use as tools, and are particularly suited for cutting tasks. Figure 7 and Table 1 summarize the results of my experimental studies of the functions of stone artifact forms. However, this is not to say, that Oldowan core forms were never used as tools. Experimentation has shown, for example, that heavy core forms with relatively sharp edges (less than 80”) are excellent wood chopping and adzing tools (Toth, 1982: 301-305). Ethnographically, the Australian aborigines, among others, have been observed using simple chopper-like forms and other tools for woodworking (Hayden, 1979). Bone-breaking for marrow acquisition is another activity for which a relatively massive tool is best. Although experiments have shown that a simple unflaked cobble will serve, heavier cores, especially those with steeper edge angles, might also have been used to crack open bones. Lewis Binford (1983 and pers. comm.) has suggested that most early stone technologies were directed towards the scavenging of animal carcasses by using core tools for breaking open bones for their marrow and for chopping dried, hardened, relict meat off bones scavenged from carnivore kills.

110

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Oldowan and Acheulean stone tools. Cob., cobble; disc., discoid; c.sc., core h.a., handaxe; cl., cleaver;

There are several .lines of evidence which may help resolve these differences of opinion. These include (1) micro-wear analysis of stone artifacts, (2) studies of bone modification, and (3) differential use of raw materials. At Koobi Fora archaeological sites, most of the artifacts are made of basalt, a material that at present is not known to produce identifiable use-polishes. A small percentage of the raw material from some of the Koobi Fora sites is fine-grained siliceous rock (“chert”, “chalcedony”), that is amenable to the analytical techniques developed by Keeley (1980) for studying European flint artifacts. Nine of 56 artifacts so far examined exhibited wear patterns that could be interpreted along functional lines. All of these were unretouched flakes or flake fragments. The functions suggested for these artifacts were (1) animal butchery/meat cutting (four examples), (2) wood-working, including sawing and scraping (three examples), and (3) cutting of soft plant matter (two examples) (Keeley & Toth, 1981). It is interesting that none of these used pieces would have been placed in the “tool” category typologically. More recently I examined a “classic” bifacial chopper of chert from site FxJjSO at Koobi Fora (rare, since most cores are of lava) for use-wear traces. Although the specimen was very fresh, no polishes or other diagnostic features were observed. A technology similar to that seen in the Oldowan can be observed in the Lower Palaeolithic of Europe. Keeley (1980) examined artifacts from Middle Pleistocene

Steep chopper Acute chopper Polyhedron Bifacial discoid Core scraper Acute flake scraper Steep flake scraper Flake Handaxe Cleaver (bit) Pick (steep edge) Hammerstone Anvil

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sites in England, including Clacton-on-Sea. This assemblage is essentially a Mode I (“Clactonian”) technology characterized by simple cores made on flint cobbles, as well as on flakes and retouched flakes. The majority of cores from Clacton did not have observable use-polishes; most of the used pieces were flakes and retouched flakes, interpreted mainly as wood-working, hide-working, and butchery tools. This study suggests that flake-tools were used at least as much as core-tools in some Mode I industries. Bunn (1981, 1982), Potts & Shipman (1981) and Potts (1982) have found evidence of animal butchery at several early sites. Fine striations microscopically interpreted as cut-marks have been identified on the bones of a wide range of mammalian species, from small bovid to elephant sizes. Many of these marks occur macroscopically as single striae or intersecting multiple striae. Under a scanning electron microscope these marks consist of numerous fine parallel tracks. Experiments show that similar modification can be made with sharp unretouched flakes (often producing the single striations) and unifacially or bifacially retouched flakes (producing the intersecting striations from irregularities in the working edge) (Figure 8).

\

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Figure 8. Macroscopic patterns of bone striae produced by different artifact edges. With scanning electron microscopy, each groove actually consists of multiple parallel tracks.

The striations are found in anatomical areas that are consistent with skinning, dismembering, and removing meat from bones (Bunn, 1982). This strongly suggests that early hominids butchered carcasses, acquired through hunting or scavenging, which had reasonable amounts of meat on them. The presence of numerous cut-marks implies that sharp stone artifacts, especially flakes and retouched flakes, had been used at Olduvai and Koobi Fora sites. This does not, however, preclude the use of some Oldowan core forms as butchery tools, as Binford has suggested. Potts (1982:. 117) has reported several signs of modification on Olduvai bones that appear to be chop-marks, perhaps signs of bone breaking, dismembering, or chopping off dried meat. Leakey (1971) has reported other evidence suggesting that some Oldowan cores may have been used as tools at Olduvai Gorge. There is a curious lack of lava dkbituge associated with most Oldowan/Developed

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Oldowan sites in Beds I and II, despite an abundance of lava cores (“choppers”, “polyhedrons”, etc.) It thus appears that flaked lava cores were transported to the sites. In contrast, &bituge of quartz and quartzite is much more common, as are small retouched forms (light-duty scrapers, etc.) in these materials. Quartz and quartzite cores are not very common in Bed I, but predominate in Bed II. This apparent differential treatment of raw materials may imply different functions as well. For example, it is possible here that quartz and quartzite flakes and retouched pieces were frequently used, and, in the lower levels, commonly transported tool forms, while, in lava, cores rather than flakes may have been curated and transported as tools, or as highly curated, infrequently flaked cores. To sum up, it seems likely that flake-tools were a very important part of Oldowan technology, and, in my estimation, probably were at least as important as the so-called “core-tools”. Many of the Oldowan “core-tool” forms could have simply been byproducts of flake manufacture. Oldowan Technology as an Indication of Low Cognitive Skills?

To describe the Oldowan as a fairly simple, opportunistic industrial mode does not necessarily imply that early hominids had low cognitive skills. We must keep in mind that stone artifacts (and material culture in general) need not reflect cognitive ability. An interesting investigation of the possible reflection of cognitive abilities in evident technological skills was conducted by Wynn (1979) in which he applied principles proposed by the Swiss psychologist Piaget for judging developmental cognitive levels, to aspects of Lower Palaeolithic stone assemblages from East Africa. In his study, Wynn examined early artifact forms for symmetry of planform, symmetry of cross-section, and evidence of the ability to create an arbitrary straight edge. He argued that these features can be seen in later Acheulean forms at Isimila, Tanzania, but not in the Oldowan forms from the lower beds of Olduvai Gorge. He infers rightly, I think, that later Acheulean hominids (presumably late Homo erectus or archaic Homo sapiens) had relatively sophisticated cognitive skills. He goes on to suggest that the makers of the Oldowan assemblages (presumably Homo habilis or early Homo erectus) did not have these skills. This may be true, but we must be cautious in making such statements, since lithic technology may not reflect true cognitive ability. Some late Pleistocene and Holocene assemblages from Southeast Asia, Australia, Tasmania, and the North American west coast, for example, are certainly the products of Homo sapiens sapiens, with modern cognitive abilities, but are still essentially Mode I technologies that would fail to meet Piaget’s criteria for advanced cognition. On the technological side, we must remember that most Oldowan artifacts were made from cobbles or chunks of raw material. It is much more difficult to shape a cobble or chunk into a symmetrical, straight-edged form by flaking than it is to shape a large flake. The knapping of large flake blanks is a hallmark of Acheulean technology after 1.5 million years ago, and often produced highly symmetrical artifacts. However, when Acheulean knappers flaked small cobbles, they normally produced Oldowan-like forms. It is clear that early stone tool-making hominids did have a good sense of the mechanics of stone fracture and a fundamental sense of the geometry of core manipulation. Normally one needs an acute angle on the edge of a core to remove a flake by percussion. It is clear that Oldowan hominids were able to find these angles on cores and to strike the cores with the proper force, at the proper point of percussion. Modern beginning knappers usually do not exhibit this ability until they have several hours of flaking practice. The core forms modern beginners produce early on are characterized by steep edges, small flake scars, and large amounts of battering from the hammerstone.

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N. TOTH

The Oldowan as an Essentially Expedient Technology?

Binford (1978) makes a distinction between tools that are retained for future use (curated tools) and those that are made and used in response to an immediate need without much premeditation (expedient tools). He suggests that earlier technologies, such as the Mousterian, were essentially expedient ones, while others, such as Upper Palaeolithic industries of Western Europe, were curatorially organized. Many prehistorians apparently feel that early stone technologies do not exhibit patterns that suggest much foresight and premeditation, and that these technologies are the product of very simple organizational systems. While I certainly do not feel that Oldowan technologies were as premeditated and as carefully curated as many later technologies, there is evidence that Oldowan hominids habitually transported materials, presumably for future use. This evidence includes (1) direct evidence of raw material transport, (2) evidence that only some stages of flaking are represented at archaeological sites, and (3) evidence from refitting lithic materials from archaeological sites. At Koobi Fora (Isaac, 1976; Harris, 1978; Harris & Isaac, 1980) and at Olduvai (Leakey, 1971; Hay, 1976) there is good evidence for the transport of raw material and artifacts over several kilometers. I take this to indicate that early hominid technology sometimes was directed toward later use of tools, and should be regarded as curational behavior. Interestingly, chimpanzees exhibit a more expedient technology. Studies of termite and ant fishing (McBeath & McGrew, 1982; Nishida & Hiraiwa, 1982) and of nut cracking with unflaked stone tools (Boesch & Boesch, 1981; Sugiyama & Koman, 1979), show that chimpanzees rareIy transport raw materials or tools very far. Often transport distances are just a few meters, and apparently never more than several hundred meters (Boesch & Boesch, 1981). In one study of chimpanzee ant-fishing (Nishida & Hiraiwa, 1982) the maximum time between tool manufacture and use was only 17 min. While chimpanzees exhibit some premeditation, it appears to be of a much lower order than that of Oldowan hominids. It has even been argued (McBeath & McGrew, 1981) that chimpanzees in Senegal do most of their termiting in one major habitat because it contained abundant Grewia plants, the source of the best termite probes. Comparisons were also made between the actual flake populations at the Koobi Fora archaeological sites,and my predictions of the hypothetical flake populations at these sites, assuming all of the dkbitage from the excavated cores and retouched pieces was represented (Toth, 1982). A given core type produces a predictable set of flake types, and hence the manufacture of a given set of cores generates a predictable population of flake types within an assemblage. A six-type system of classification of whole flakes was employed to document which stages of flaking were represented in flaking experiments and at archaeological sites (Toth, 1982). This system was based on the presence, partial absence, or total absence of cortex on the dorsal surface of the flake, and on the presence or absence of cortex on the platform (butt) of the flake (see Figure 9). In general, percentages of completely non-cortical flakes (Type VI) tend to represent later stages of reduction of Oldowan cores. My study indicates that these later stages of flaking are disproportionately represented at these Koobi Fora sites (Figure 10, Table 2), indicating transport of partially-flaked cores to the site from another knapping location. A third line of evidence suggesting hominid transport of artifactual materials is from refitting studies at Koobi Fora sites, especially site FxJj 50 (Bunn et al., 1980). Conjoining pieces at this site were normally found very close together, suggesting that this site had not undergone serious fluvial disturbance. Though a large area was excavated, few of the artifacts from this site (about 15%) were conjoinable to others. Of 63 cores and retouched pieces, for example, only six had any conjoining dibitage within the excavated

THE OLDOWAN

I

II

REASSESSED

m

115

lx

P

Figure 9. Flake type. classification used in the analysis of I-III have cortical platforms, suggesting unifacial flaking have non-cortical platforms. Within these two divisions, fied by total, partial, and absence of cortex on the dorsal

PT Koobi Fora sites. Types of cobbles. Types IV-VI flakes are further classisurface.

Table 2. Comparison of the excavatedflake populations from Koobi Fora computer-simulated predictions of expected flake populations. Percentage replicated denotes those that could be assigned to reduction modes

I FxJj

1

FxJj 3 FxJj

10

FxJj 50 FxJj 18GL FxJj 33 FxJj 63

0 (0.00)

II

III

IV

V

Site Simulation Site Simulation Site Simulation Site Simulation

3 0 2 0 3 24 31

(0.06) (0.00) (0.08) (0.00) (0.03) (0.07) (0.09)

1 6 0 4 2 6 85 107

(0.04) (0.12) (Oao) (0.20) (0.03) (0.06) (0.24) (0.32)

0 (040) 2 (0.04) 0 (0.00) 1 (0.07) 1 (0.01) 5 (0.05) 45 (0.13) 37 (0.11)

0 (0.00) 3 (0.06) 0 (0.00) 2 (0.07) 1 (0.01) 8 (0.08) 25 (0.07) 19 (0.06)

2 24 4 8 23 35 118 83

(0.09) (0.47) (0.3 1) (0.37) (0.33) (0.36) (0.33) (0.25)

Site Simulation Site Simulation Site Simulation

8 58 0 39 2 3

(0.02) (0.03) (0.00) (0.06) (0.01) (0.01)

9 (0.02) 152 (0.09) 1 (0.17) 93 (0.13) 5 (0.03) 6 (0.02)

3 (0.01) 74 (0.04) O(O.00) 31 (044) 0 (0.00) 24 (0.07)

21 (0.04) 98 (0.06) O(O.00) 60 (0.09) 8 (0.04) 10 (0.03)

220 775 2 295 58 174

(0.43) (0.46) (0.33) (0.43) (0.29) (0.49)

VI

Total

20 13 9 4 42 39 56 54

(0.87) (0.25) (0.69) (0.20) (0.61) (0.41) (0.16) (0.16)

23 51 13 21 69 96 353 331

252 535 3 174 126 140

(0.49) (0.32) (0.50) (0.25) (0.63) (0.39)

513 1692 6 692 199 357

sites with of cores

Percentage cores simulated

100% 100% 92% 79%

83% 85% 88%

area. From the model of flaking stages represented by the major refitted pieces (Figure 11) it is clear that the complete reduction sequences are rarely represented within the excavated areas. The model I have proposed for early hominid tool use thus includes transport of a wide range of lithic raw materials around the landscape for future use (simple curation behavior) (Toth, 1982). Some of this raw material “drops out” at concentrations that archaeologists call “sites”. The model I envision is one of hominids testing out raw materials from stream gravel bars, and transporting the best pieces to activity areas. When sites are abandoned, the best lithic materials (large cores and flakes, a few hammerstones, etc.) will be carried off for future use. Perhaps many sites were re-occupied over time before final burial. New material may have been brought to these localities, and old material that had been discarded there might have been re-used and reduced further. Finally the sites were completely abandoned, perhaps sometimes as a direct result of floods that led to site burial.

116

N. TOTH Flake

predictions

100,

I

FxJj

I

FxJj

IO

I

1

FxJj50

loo-

FxJj

3

FxJj

18GL

I

I JImlscpP3u

I PrnIPPH

Fx Jj 33 Site

Replicated tools

FxJj63 Site

Replicated tools

Figure 10. Comparison of the excavated flake populations from Koobi Fora sites with computer-simulated predictions of flake populations. Note that later stages of flaking (represented by non-cortical, type VI flakes) occur in greater than expected proportions at most excavated sites.

Early Hominid Dependence upon Lithic Technology?

It is often assumed that as lithic technology progressed, early hominids became more and more dependent on stone tools for a wide range of activities. In the long run, this appears certain. But in the earlier periods of stone technology, there may have been much less dependence upon stone tools. At Koobi Fora, especially in the Upper Member, there is a fascinating dichotomy in the distribution of hominid fossils and archaeological sites. (Isaac & Harris, 1978.) .

THE OLDOWAN REASSESSED Conjoining

pieces:

Beginning ‘-11

117

stage of flaking Middle

?--I,

End

--III---II--II

I -,I I -I, I -II T--11 Ill--111 II -” 1” -” “I-“-“--v v--v V-V V--v v--v V-V-? II-II-C(U.

Ch)

?-?-C(U.Disc) II

v-v-v-v-

C(B.

v-v-c

Ch)

v-C

(B. Ch)

v-C

(B. Ch) (Poly.)

Figure 11. Chart showing stages of flaking represented at site FxJj 50 based on conjoining pieces. The beginning stage of flaking was detined as a flake type I (cortical butt, total cortex dorsal surface) conjoining with at least one other flake. The end or terminal stage of flaking was defined as a core (C)with at least one conjoining flake. Roman numerals represent the six flake types. Note that complete reduction sequences are rarely represented in the excavated area.

Hominids, especially the more gracile forms generally attributed to the genus Homo, tend to be found in the vicinity of the proto-Lake Turkana (Behrensmeyer, 1973, while archaeological sites tend to be found inland along stream courses in the alluvial valleys. There are some obvious reasons for this pattern. First, bones are more likely to be preserved in low-energy situations, such as in proximity to the lake, where stream gradients are low. Second, stone tools tend to be found upstream, nearer the sources of suitable raw materials for flaking. The interesting pattern that emerges at Koobi Fora is that hominids appear to have transported raw materials a few kilometers from their gravel sources to form low-density archaeological sites, such as the Lower Member sites at Koobi Fora. These were near the lake at a time when its level was much higher, and the shore over 10 km inland from the present shoreline. Normally, however, the proto-humans did not carry and discard enough lithic material in lake margin environments to form many recognizable archaeological sites. This was especially true in Upper Member times, when the lakeshore was in approximately its present location (Findlater, 1978). The fact that remains of large-brained, probable tool-making hominids occur relatively often in these

118

N. TOTH

lake-margin areas suggests that foraging in these areas did not depend much on stone tools. Some cut-marked bones in these areas (Bunn, 1981, 1982), suggest some lithic transport (or the transport of parts of butchered animal carcasses), but very few concentrations of artifacts have been found near the lake. It is possible that early hominids made much use of relatively perishable or unmodified material such as bone, wood, horn, or shell. Brain (1982) has reported polished and striated bones interpreted as digging tools from early Pleistocene deposits at Swartkrans and Sterkfontein, South Africa. Perhaps shells were also used for cutting tools at Koobi Fora. Fractured shell edges can be very sharp (P. Williamson, pers. comm. and pers. obs.) and might even make cut-marks on animal bones. Conclusions Some of the major conclusions drawn from my study are that (1) many of the Oldowan core forms could simply be by-products of flake manufacture, and may not really represent deliberate stylistic norms, (2) unretouched flakes were probably at least as important as cores or retouched flakes as tools, especially for activities related to animal butchery, (3) stone technology is not necessarily a good criterion for judging cognitive abilities, (4) Oldowan technology can be considered as a simple curated technology, (5) early stone-tool making hominids were not necessarily dependent upon the use of stone tools in this early period. These conclusions are principally drawn from analytical and experimental studies of the Koobi Fora archaeological occurrences in northern Kenya, dated to between 1.9 and 1.4 million years ago. But, as White has pointed out (in Rosenthal, 1982), these early hominids were probably very opportunistic. Whether the behavioral patterns seen at one locality can be used as a model for all early hominid tool-using groups is doubtful. We might expect a wide range of variation in the behavioral, adaptive, and technological patterns depending upon local circumstances. Future research should help clarify the range of these patterns as seen in the prehistoric record through diligent survey, careful excavation of the best-preserved sites, further actualistic studies, and new analytical approaches to the archaeological record. Acknowledgements The research outlined in this article was made possible by a grant from the National Science Foundation to the Koobi Fora Research Project, directed by Richard Leakey and Glynn Isaac. The archaeological research at Koobi Fora was directed by Glynn Isaac and John W. K. Harris, who provided advice and logistic support during the course of my study. Special thanks to Kathy Schick, Tim White, John Parkington and John W. K. Harris for valuable suggestions regarding this paper, and to Judith Ogden for the drawings in Figure 1. References Behrensmeyer, A. K. (1975). Taphonomy and palaeoecology in the hominid fossil record. Yearbook of Physical Anthropology 19,365O. Biberson, P. J. (1961). Le Pal&olithique InfPrieur du Maroc Atlantique. Rabat: Pubiic Servicedes Antiquities du Maroc, 17. Binford, L. (1979). Organization and formation processes:looking at curated technologies. Journal of Anthropological

Research 35,255-273.

Binford, L. (1983). In Pursuit ofthe Past. New York: Thames and Hudson. Boesch, C. & Boesch, H. (1981). Sexdifferences in the use of natural hammers by wild chimpanzees: a preliminary report. Journal of Human Evolution 10,585-593. Brain, C. K. (1981). The Hunters or the Hunted? Chicago: University of Chicago Press.

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