The Palaeolithic record
Abstract and Keywords
This article deals with some of the major developments in hominin technology, subsistence, social behavior, and cognition, which are outlined by the archaeologists of the Paleolithic. One of the innovative technologies, Mode 1 tools, consists of the three basic varieties of stone tool that include hammers, cores, and flakes. The knapper In Mode 1 technology uses a hammer, which is a roundish hard stone, to strike the edge of another stone, termed a core. Hominins used the sharp flakes to butcher carcasses of medium (antelope-sized) and occasionally large (e.g. giraffe) mammals. Hominins also used stone hammers and cores to smash long bones for marrow, and at some Mode 1 sites the presence of stones with crushed surfaces indicates that the hominins were pounding more than just bones possibly also roots or corms, though pounding meat itself would have rendered it easier to digest. Homo erectus produced a new kind of lithic technology that archaeologists term Mode 2 or Acheulean. All of the Mode 1 elements continue in Mode 2, but were augmented by a very different kind of stone tool termed “biface”. A biface is large stone tool made by trimming the margins of a core or large flake “bifacially”. Bifacial trimming resulted in two types of tool with sturdy cutting edges around most of their margins that include cleavers with an unmodified “bit” at one end and handaxes whose sides converged to a narrow tip or point. Fire also appears to have been a component of Homo erectus technology.
Archaeology studies the tools, structures, and refuse produced by individuals and groups who lived in the near and distant past. Most archaeologists concern themselves with historic and recent prehistoric time periods, roughly the last 12,000 years. But a small group of archaeologists investigates the behavioural and cultural developments that marked the evolution of humans from their split from other African apes to the advent of agriculture, an immense period of time known as the Palaeolithic or Old Stone Age. Using methods and techniques developed over the last century and a half, archaeologists of the Palaeolithic have been able to sketch an outline of some of the major developments in hominin technology, subsistence, social behaviour, and cognition.
27.2 The earliest evidence of hominin activity
The oldest known hominin archaeological site with stone tools is the 2.6‐million‐year‐old site of Gona, in Ethiopia (Semaw et al. 1997). Earlier isolated finds of stone (p. 283) flakes stretch back perhaps as far as 3 million years ago (mya), and bones apparently cut by stone tools at Dikika, Ethiopia, date to 3.4 mya (McPherron et al. 2010), but Gona is the oldest well‐dated site where artefacts have been little disturbed by natural forces of erosion and deposition. The Gona artefacts are the earliest examples of a technology archaeologists term Mode 1, or Oldowan; no actual tools have been recovered from the Dikika site.
Mode 1 tools consist of the three basic varieties of stone tool—hammers, cores, and flakes. The principle behind stone knapping is deceptively simple: breaking rocks produces sharp edges. In Mode 1 technology the knapper uses a hammer, which is a roundish hard stone, to strike the edge of another stone, termed a core (Figure 27.1).
If the knapper uses enough force and directs the blow to a spot near the margin of the core, a flake with very sharp edges suitable for a variety of cutting tasks breaks off. The core itself also now has sharp ridges, but initially, at least, the focus of Mode 1 technology appears to have been the production and use of sharp flakes (Toth and Schick 2009) (Figure 27.2).
(p. 284) Basic knapping is not particularly difficult conceptually. There is nothing to indicate that the cognitive abilities of the earliest hominin knappers, such as those at Dikika (see above), were dramatically different from those typical of apes. The captive bonobo, Kanzi, for example, was able to pick up the basic idea fairly quickly in an experimental situation. Neither Kanzi, nor other bonobo knappers, however, have ever acquired the skill level achieved by even the clumsier Mode 1 knappers (Schick et al. 1999; Savage‐Rumbaugh and Fields 2006). Apes are not very good at identifying optimal places to strike a core, even after years of knapping. This suggests that by the time of Gona, hominins had been knapping long enough to have evolved at least a few biomechanical, and perhaps cognitive, traits linked to stone knapping. Though initially African, Mode 1 technology eventually spread into Asia and southern Europe. By 1.8 mya it was present on the Iberian Peninsula and in the Caucasus mountains.
Hominins used the sharp flakes to butcher carcasses of medium (antelope‐sized) and occasionally large (e.g. giraffe) mammals; cut marks on bones preserved at (p. 285) many Mode 1 sites provide direct evidence for this butchery. Hominins also used stone hammers and cores to smash long bones for marrow, and at some Mode 1 sites the presence of stones with crushed surfaces indicates that the hominins were pounding more than just bones (Mora and de la Torre 2005), possibly also roots or corms, though pounding meat itself would have rendered it easier to digest (Wrangham 2009). It is impossible to measure how significant meat was to the diet, at least from the archaeological evidence, but it was almost certainly more important than it is currently for modern apes.
27.2.3 Social behaviour
The archaeological evidence provides little direct evidence for social organization or behaviour. Most of the excavated sites cover small areas, at most a few tens of square metres, which in turn points to small size for the social unit active at the site. There is no way to tell if these were cohesive social units, or shifting fission‐fusion groups similar to those typical for modern chimpanzees. By identifying sources of raw material used for stone tools, however, we can estimate territory sizes up to 150 mi2, compared to 5–15 mi2 for chimpanzees.
For almost two million years, 3.4–1.6 mya, early hominins relied on Mode 1 technology. It enabled them to exploit foods that apes rarely use, and adapt to life in more open tropical woodlands. It even enabled some of these early hominins to expand out of Africa into southern Europe and Asia. But in most respects these early hominins were apes. The first dramatic shift away from an ape way of life emerged about 1.5 mya with the appearance of Mode 2 technologies.
27.3 Developments in the Homo erectus era
About 1.8 mya Homo erectus appeared in East Africa, and very soon after in western and eastern Asia. It was taller, had an almost modern locomotor anatomy, was less sexually dimorphic, and had a larger brain. Homo erectus was different enough anatomically that many palaeoanthropologists believe its appearance represented a new evolutionary grade that was much more human‐like, and less ape‐like, than the many hominins that preceded it. The archaeological record corroborates this assessment.
(p. 286) 27.3.1 Technology
Initially Homo erectus produced a Mode 1 technology, and in many parts of Asia continued to make Mode 1 tools for hundreds of thousands of years. But in Africa, Homo erectus produced a new kind of lithic technology that archaeologists term Mode 2 (also known as Acheulean). All of the Mode 1 elements continue in Mode 2, but were augmented by a very different kind of stone tool termed a ‘biface’. A biface is large stone tool (>10 cm in maximum dimension) made by trimming the margins of a core or large flake ‘bifacially’; i.e. placing trimming blows onto both faces of the tool. Bifacial trimming resulted in two types of tool with sturdy cutting edges around most of their margins: cleavers with an unmodified ‘bit’ at one end, and handaxes whose sides converged to a narrow tip or point (Figure 27.3).
Experimental replication and use, and analysis of wear patterns, indicate that bifaces were multipurpose tools that were especially good at butchery (Schick and Toth 1993).
Bifaces embodied several ‘firsts’ in technical evolution. They were the first tools with an imposed overall shape, in this case bilateral symmetry. More importantly, they were the first ‘tools’ in the modern sense. Earlier Mode 1 tools resulted from a well‐learned procedure: strike off a flake, use it, discard (p. 287) it. They did not exist outside of the context of their use, but bifaces did. Homo erectus made them, used them, carried them around, and used them again, often for different tasks. They were continuously at hand, and continuously participated in Homo erectus life, suggesting a level of commitment to technology unseen in earlier hominins.
Fire also appears to have been a component of Homo erectus technology. The earliest possible evidence for fire consists of charred, butchered bones from the 1.4‐million‐year‐old cave of Swartkrans in South Africa (Brain and Sillen 1988), but lack of any obvious hearths makes many archaeologists sceptical. The earliest generally accepted evidence for fire is considerably later, 790 kya at Gesher Benot Ya'aqov in Israel (Alperson‐Afil et al. 2007). However, the rapid expansion of Homo erectus into many new habitats, including temperate climates, would certainly have been aided by use of fire for warmth, predator deterrence, and especially for cooking.
Mode 2 technology eventually found its way into the Indian subcontinent and Europe, but not until after 1 mya. Mode 2 has occasionally been described as ‘changeless’ or ‘in stasis’, but this is not quite true. Yes, the range of stone tools did not change for almost one million years, but the tools themselves did change—500,000‐year‐old bifaces were more regular in shape than 1.6‐million‐year‐old bifaces, and had three‐dimensional symmetry.
Features in anatomy, brain size, and teeth, suggest that Homo erectus relied more on meat than earlier hominins. Primatologist Richard Wrangham (2009) has argued that cooking was a key component to this shift. Unfortunately, as noted above, archaeology provides only minimal evidence for fire prior to 790 kya, and no solid evidence for hunting until even later. We know that hominins using Mode 2 tools butchered large animals, and we even have evidence that they used bifaces on wood, perhaps to make spears (Dominguez‐Rodrigo et al. 2001).
27.3.3 Social behaviour
The size of Mode 2 sites suggests that Homo erectus face‐to‐face groups continued to be small, certainly fewer than 50, and there is no indication that these hominins congregated in larger communities. They did learn tool use and tool‐making from one another. All appeared to have shared an idea of what a handaxe should look like. This suggests a socially learned standard that was more elaborate, with more components, than anything done by apes.
(p. 288) Bifaces present an unresolved enigma for palaeoanthropologists. As noted, hominins produced the same shape in Africa, parts of Asia, and Europe for hundreds of thousands of years. This shape was a cultural construct (unless there was a biface gene, which seems unlikely) with mind‐numbing conservatism. Modern cultural constructs over the past 20,000 years have changed more or less steadily, for a variety of reasons. Something must have been very different about the role played by bifaces in Homo erectus life compared to the role of tools in the modern world.
The archaeological record documents some significant developments in cognition. Bifaces required hominins to coordinate spatial cognition with shape recognition, something apes never do (Wynn 2002). Mode 2 knappers also had to attend to more things when making bifaces—not just knocking off flakes, but also attention to the overall shape of the core. Both of these developments indicate that Homo erectus could hold more in mind than earlier hominins (Gibson 1993), something cognitive scientists refer to as working memory capacity.
Homo erectus, many using Mode 2 tools, spanned the period of 1.8 mya–500 kya with little dramatic change. They possessed a successful, technically‐assisted adaptation that enabled them to live in many different habitats. Still, their culture was very different from that of apes, and from ours.
27.4 The seeds of modern life
Sometime about half a million years ago, hominins developed greater cultural complexity, as indicated by a greater variety of cultural activities, a greater number of steps involved in many activities, and more interdependency in the steps. Of course, 500 kya was much closer to the present than 2.5 or 1.5 mya, and many more sites have survived to be studied. Thus, some of this complexity reflects better preservation and better samples, but not all. Also, it is not as easy to generalize about the archaeological record of entire continents as it was for Mode 1 and Mode 2 times. Archaeological patterns in Africa, Europe, and Asia began to diverge from one another, and only one of these cultural trajectories led to ours. Nevertheless, there are enough similarities to provide an outline of important developments.
Although many hominins (in Africa and Europe this was a form known as Homo heidelbergensis) continued to make bifaces, the focus in Mode 3 knapping shifted to the production of flakes with a variety of working edges. Knappers developed techniques for managing the volume of cores so that they yielded either a (p. 290) maximum number of large flakes, or even flakes with a particular shape (Figure 27.4). The most famous of these ‘prepared core’ techniques is known as Levallois.
Knappers then modified the flake edges into shapes and angles that best performed the task at hand. The result was a large array of slightly different edge varieties that performed a concomitant variety of tasks, yielding many different core management techniques and much regional variability.
The oldest hunting spears yet found date to about 400 kya from the German site of Schöningen. Hominins cut down small spruce trees and shaved the trunks into 2‐metre long shafts pointed at both ends (Thieme 1997).
European hominins hunted large mammals. At Schöningen they hunted horses, at Hoxne in England they hunted roe deer, and at Boxgrove in England they hunted horses and giant elk. Archaeologists ‘see’ hunting in Europe more clearly than elsewhere because successful foraging in temperate latitudes generally requires greater reliance on animal products than in the tropics, but also because Europe is just much better known archaeologically. Plants do not preserve well in the archaeological record, but they were likely to have been an important part of the diet.
27.4.3 Social behaviour
About this time, the archaeological record begins to show evidence for a different kind of social life from that practised by earlier hominins. Group size continued to be small, and even though these hominins made regular use of fire, there is no evidence for long‐burning hearths that could have been the focus of group interaction. But they had begun to mark their social identity, as evidenced by the site of Twin Rivers in Zambia, where residents collected five different colours of mineral, some from different distant locations, and ground them into powder (Barham 2002). They were colouring something, but what, and why? Most archaeologists suspect that they were colouring their bodies just as modern humans colour their bodies to change how they appear to others.
Another first was mortuary treatment. At Sima de los Huesos in Spain, also about 400 kya, hominins placed the remains of over 30 individuals into a vertical shaft deep in a limestone cave (de Castro and Nicolas 1997). The remains are jumbled together. This is clearly not where they died, and there is no obvious natural agent that could have carried them there. It would be an over‐interpretation to equate this with modern mortuary rites, but it does suggest added complexity in the social lives of these hominins.
(p. 291) 27.4.4 Cognition
Hominins who lived half a million years ago had brain sizes in the low end of the modern range (1200–1300 cc). Not surprisingly, the archaeological record documents changes in cognition. Spatial cognition achieved its modern scope at this time; core management techniques and bifaces with beautiful three‐dimensional symmetry attest to a modern ability to conceive of and control three‐dimensional Euclidean space (Wynn 2002). Technical cognition was also very sophisticated. Many of the core management techniques required flexible procedural cognition equivalent to that used by modern craft production, as well as an increase in working memory capacity (Wynn and Coolidge 2010). Use of pigments to alter appearance suggests developments in social cognition, especially an enhanced theory of mind, the ability to imagine what another sees and knows. Thus, these hominins were cognitively modern in some, though not all, respects.
Neanderthals were a population of European archaic humans whose evolutionary lineage split from that of Homo sapiens about 500 kya and who disappear from the archaeological record sometime after 30 kya. Culturally they were very similar to the African ancestors of modern humans who lived at the same time, but they did not acquire many of the features of modern life eventually associated with modern human behaviour. Their technology, known by archaeologists as ‘Mousterian’ or ‘Middle Palaeolithic’, continued the emphasis on core management and flake technology developed by their European ancestors, and showed little evidence of innovation. They did introduce hafting of stone points onto spears, but this was about the only significant technological innovation in their 200,000‐year tenure. Neanderthals were very effective hunters, often focusing on the largest mammals available on the local landscape (including mammoth in Northern Europe). They lived out their lives in small face‐to‐face groups, and had little contact with other Neanderthals outside their local territories. Neanderthals practised a minimal kind of corpse treatment, placing bodies in protected places, occasionally scooping out shallow pits. They made extensive use of pigments, again probably for body decoration, but produced no depictive images and little or nothing resembling modern symbol use. Cognitively they were adept stone knappers, and had expert knowledge of their local territories, but their heavy reliance on well‐learned procedural memories and failures to innovate may have put them at a disadvantage when modern humans arrived in Europe about 40 kya.
(p. 292) 27.6 The emergence of modern culture
The evolution of Homo sapiens can be divided into two phases. Modern anatomy first appeared about 200 kya in Africa (Shea et al. 2007), but for the next 100,000 years the archaeological signature of these ‘anatomically modern humans’ was decidedly archaic. Only after 100 kya did populations in Africa begin to acquire features of behaviour that clearly distinguished them from archaic humans. And after 70 kya, these behaviourally modern people began an expansion out of Africa that rapidly extended over the inhabitable world, including Australia and the New World.
Although developments in stone tools have often been touted as accompanying the emergence of modern behaviour, especially the manufacture of long, thin flakes known as blades, such techniques were no more difficult or complex than the techniques of Mode 3 knapping. Mode 3 technology, however, included only a few non‐lithic tools (e.g. the Schöningen spears), whereas after 100 kya in Africa, Homo sapiens began producing a greater variety of tools in bone, including bone projectile points and bone awls. They, too, hafted points onto spears. These developments required no cognitive leap beyond what we know for archaic humans. The most significant change in technology left little direct evidence—the gradual shift from ‘maintainable’ to ‘reliable’ tools.
Reliable tools are ones that require more time and effort to make, but which are more effective when actually used. They are often multicomponent tools with complex linkages of elements. One example of such a system is a harpoon set, which includes a spear thrower, spear, detachable fore‐shaft, and thin bifacial stone projectile point or barbed bone point. These are time‐consuming to make, but very effective killing devices (Bleed 1986). The earliest such devices appeared in Europe only about 20 kya, but simpler antecedents appeared in Africa as early as 90 kya (Yellen et al. 1995). Equally reliable are traps, which are remotely operated hunting facilities. Traps are rarely found in the archaeological record, because, until the last few thousand years, they would have consisted primarily of wood and cordage, which do not preserve well. The oldest direct evidence is only about 10,000 years old, but indirect evidence extends much further back—75,000‐year‐old sites in South Africa have yielded remains of blue duiker, a small antelope that inhabits dense undergrowth and which is almost invariably captured by means of traps because it is extremely difficult to hunt using projectiles (Wadley 2010).
(p. 293) 27.6.2 Subsistence
As with technology, the subsistence of modern humans was initially no different from that of archaic humans such as Neanderthals. One‐hundred‐thousand‐year‐old archaeological evidence documents two trends. The first was a broadening of the range of resources hunted and gathered. People began to adjust their foraging endeavours according to the nature of locally available resources, and they began to include foods rarely eaten by archaic humans, such as fish and shellfish. The second trend involved scheduling of foraging activities to optimize use of seasonally available resources. This included the use of fire to alter landscapes and change the foraging schedules of prey animals. And for the first time, the range of resources preserved in archaeological sites suggests a modern form of hunting and gathering with a marked division of labour by age and sex (Kuhn and Stiner 2006). In other words, the modern form of hunting and gathering evolved after 100,000 years ago, with Homo sapiens.
27.6.3 Social behaviour
The most significant behavioural developments associated with modern humans were in the domain of social behaviour. By the time of the European Upper Palaeolithic (ca. 40–12 kya) some archaeological sites were large enough to suggest face‐to‐face group sizes of well over 100, and there were more groups on the landscape. Even taking into account the better preservation of more recent sites, there were many more later Palaeolithic sites, over a shorter time range, than those of archaic humans. Finally, later Palaeolithic people were the first to establish and maintain long‐range contacts between groups. Evidence for this comes from raw material, and occasionally artefacts, found hundreds of kilometres from their point of origin (Ambrose 2001).
Later Palaeolithic people developed material systems to mediate this larger‐scale social world. Evidence for beads extends back almost to 100 kya in South Africa (d'Errico et al. 2005; d'Errico and Vanhaeren, this volume). Although interpretations of their significance have been controversial, most archaeologists agree that they must have been social markers of some sort, which in turn suggests interaction outside the daily face‐to‐face group (all of whom would already know someone's status). At the same time, the archaeological evidence includes the appearance of styles of artefacts, including stone tools that were distinctive for small regions, and perhaps tied to specific face‐to‐face groups.
Arguably the most famous developments of this time period are the traditions of depictive art. Though the archaeological record has yielded earlier, isolated, enigmatic, examples of possible depictions, the first convincing examples date to 50 kya (p. 294) (d'Errico et al. 2003). The most spectacular examples are the cave paintings of the European Upper Palaeolithic (Figure 27.5), but examples of equivalent antiquity and sophistication occur in Africa, South Asia, and Australia. Interpretations of this art have ranged from the mundane to the fanciful. What is perhaps most telling is its resonance for anyone who sees it. It reminds us of ourselves.
Consider several of the activities apparent from the archaeological record of modern humans:
1. Reliable, multicomponent tools and remotely operated facilities such as traps.
2. Diversified, seasonally scheduled and managed hunting and gathering with sex‐ and age‐based division of labour.
3. Large social groups with long distance social networks.
What all of these activities share is a reliance on long‐range planning ability, not just over hours and days, but over months and even years. It is often assumed that the emergence of symbolism and language are sufficient to account for these planning abilities. However, the findings of modern cognitive science indicate that planning and strategizing requires executive functions that have a clear neurological basis separate from the language‐dedicated networks of the brain. A key component of executive functions is working memory capacity, the ability to hold information in attention and process it (Coolidge and Wynn 2005). Thus, (p. 295) though symbolic ability was clearly required for modern cognition, developments in executive reasoning ability were also necessary.
By the end of the Palaeolithic, roughly 12 kya, all of the components of modern culture were in place, and provided the foundation for the spectacular developments that followed.