Setting the Stage

Humans occupy a rarified position in the modern world. We are ubiquitous, ecologically dominant, and technologically unrivaled. And yet, three million years ago, our ancestors were a rather unremarkable species of ape — albeit one that walked around on two legs rather than all fours. What happened? How did we become so dominant, so pervasive, so quickly?

The secret to our success lies in the intertwined evolutionary histories of our anatomy (especially our large brains), our behavioral ecology (the remarkably flexible and diverse strategies we use to fuel those brains and overcome many of nature's other challenges), and — perhaps most importantly — our capacity for cumulative culture (our "ability to accumulate socially learned behavior over many generations...leading to the evolution of behaviors than no individual could invent on their own," Boyd & Richerson 1996). The goal of Paleolithic archaeology is to describe and explain the evolution of these interrelated suites of adaptations (as well as associated aspects of our biology and culture) through studies of the material record of past human behavior.

What is Technology?

The material record — the archaeological record — largely consists of bits and pieces of ancient technology. These are the tangible items mentioned at the onset: stone tools, fire pits, cave paintings, and the like. But technology is far more than just physical items created to accomplish various tasks. Technology is also the intangible ‘know-how', the capacity for making and using those items.

Digging a bit deeper, technology is the product of both culture (i.e., shared learned practices and beliefs) and biology (e.g., the toolmakers' behavioral ecology; their capacity for culture). As a result, technologies will vary according to the task at hand, the possible solutions known to the population, the cost of failure, as well as myriad other factors (see below). In turn, and of great interest to the archaeologist, technologies will often reflect aspects of the biology and/or culture of their creators.

Paleolithic Technology is a Window to the Deep Past

The Paleolithic (the ‘Old Stone Age') begins ~2.6 million years ago with the emergence of the archaeological record and the first material evidence of early human technologies (Schick & Toth 1993, Semaw et al. 1997, Ambrose 2001, Foley & Lahr 2003, Klein 2009, see also McPherron et al. 2010). The Paleolithic continues in one form or another until the appearance of Neolithic cultures approximately 10,500 years ago, although the exact timing of this transition varies widely by geography and cultural group. The Neolithic introduces a novel way of life, one where people settle in villages and domesticate both plants and animals. In relatively short order, a few of these cultures then evolve into early states and empires.

This raises an important question. If one is interested in understanding the course and context of human evolutionary history, why not focus on this later time period, with its fine archaeological record of cities, pyramids, written records, and the like? The answer is clear. Those artifacts were created by peoples and cultures that were fully modern in every meaningful respect. When studying a pyramid, one can address questions about ancient socio-political organization, architectural skills, mobilization of labor — really an infinite number of interesting topics. If these issues are of paramount interest to a researcher, then a pyramid is an appropriate source of information for generating and testing hypotheses about the human past.

But what if one is interested in the origins of human minds, bodies, and cultural abilities? As our origins extend deep into time — greatly pre-dating ‘village life' — pyramids and the like cannot yield insights relevant to these issues. Rather, it is the Paleolithic era that saw the emergence of the genus Homo and the rise of our species, Homo sapiens. The Paleolithic witnessed dramatic changes in our anatomy, our ecology, and our capacity for cultural learning and symbolic thought. Paleolithic technologies accompanied us on our migrations out of Africa, were present at the initial rise of regional culture groups, and were featured in some of the earliest ceremonial rituals. From an archaeological perspective, if we are interested in studying the emergence and evolution of these and related adaptations, then it is to the Paleolithic record that we must turn.

Let's Get Specific; What Can We Learn?

Human evolutionary studies are unified through a shared foundational interest in the course and context of humankind's biological evolution, our cultural evolution, and the coevolutionary interplay between the two. Studies of Paleolithic technologies help inform each of these subject areas.

1. They help inform our understanding of ancient hominin biologies (with ‘hominin' referring to modern humans and our extinct kin that are more closely related to us than to modern chimpanzees). Artifact forms, for instance, often reflect a clear ecological function. Some are optimally designed for spearing large game, others are much more useful for carrying honeycomb, while still others are best employed when fishing, etc. With an eye toward inferring aspects of ancient hominin diets (and with it perhaps gaining new insights into associated features of their anatomy, ecology, sociality, etc.), functional analyses of artifacts provide a means with which to formulate and test specific hypotheses about the foraging behaviors and dietary practices of past toolmaking populations.

Artifact distributions provide a second potential source of paleobiological data. When studied at local, regional, and/or continental scales, artifact distributions reflect, to some extent, the geographic ranges of ancient toolmakers. Researchers can use this data to explore the dynamics structuring past hominin biogeographies (i.e., their distribution(s) in relation to time, space, ecology, historical constraints, etc.).

2. Studies of Paleolithic technology also inform our understanding of the course and context of hominin cultural evolution. While our present capacity for cumulative culture clearly distinguishes us from all other living animals, remarkably little is known about the evolutionary history of this adaptation (Richerson & Boyd 2005). Under what circumstance(s) did it emerge and fluoresce, and how might we use inferences of prehistoric culture to better understand the human past — as well as perhaps inform the present and future?

Again, consider artifact forms. Each is the product of a specific sequence of tasks (e.g., the numerous individual steps required to produce an ‘X'-culture arrowhead). But how does the toolmaker know that particular sequence? Is it something individually learned, is it the product of social learning, is it a combination of the two, or is it something else entirely — perhaps genetically-encoded instructions? Through theoretical and experimental modeling of artifact manufacture and cultural mechanics — the nuts and bolts of how culture ‘works' as a means of information transmission — archaeologists can begin to infer some aspects of prehistoric hominin cultural abilities: for example, the minimum cultural capacity of a tool-making population. With this data in hand, and with numerous populations sampled, researchers can then begin to address really interesting questions: when, where, and why do cultural capacities seemingly improve or decline?

In addition, once cumulative culture is firmly in place within a population (see Middle Stone Age/Middle Paleolithic below), technologies will begin to reflect population-level differences as a simple byproduct of cultural processes. The resulting material differences figure prominently in studies of prehistoric hominin culture, society, migration, trade, etc.

3. Lastly, studies of Paleolithic technology help inform our understanding of the coevolutionary interplay between hominin biological and cultural adaptations. Simply stated, adaptations do not evolve in isolation — a slight improvement in one feature will often lead to modifications in others. At issue for the Paleolithic archaeologist: how — if at all — are specific biological and cultural adaptations interrelated? For instance, are there deep causal relationships amongst the evolution of material culture (e.g., Paleolithic technology) and profound changes in past hominin diets, anatomies, and cognitive abilities? Did technology, diet, intellect, and cultural capacity co-evolve in a series of feedback loops, ultimately resulting in modern humanity? Painting with very broad strokes: yes they almost certainly did — although fleshing out many of the specific details will require further investigation and debate.

The archaeological record also documents the rise of increasingly sophisticated technologies through time (Schick & Toth 1993, McBrearty & Brooks 2000, Ambrose 2001, Foley & Lahr 2003, Klein 2009). ‘Greater sophistication' corresponds to some or all of: (1) an increased number of ordered steps in production and use, (2) an increased difficulty-level associated with executing some of these steps, and/or (3) a decreased likelihood of someone independently inventing the technology. Greater sophistication reflects the deep interplay of brains (i.e., raw intellect), demography (i.e., population size and composition), culture, as well as the technologies required to sustain populations.

For example, imagine a useful but fairly complex innovation like bone harpoon technology. Its conception, production, use, and long-term retention within a culture will require a baseline amount of cognitive and cultural capacity on the part of the toolmaking population. Assuming all else is equal, larger populations will produce and retain innovations at higher rates than smaller ones (Shennan 2001, Henrich 2004, Richerson et al. 2009, Lycett & Norton 2010). Thus, with sufficient time and a sustained improvement in foraging success (perhaps due to the introduction of harpoon-based fishing) — meaning more food for everybody — our hypothetical population may increase in size, as would their ability to produce and retain additional innovations. In turn, this advance may initiate and support additional bouts of evolutionary change. Note though that such feedback loops can also work in reverse — a decrease in population parameters (size, density, etc.) may result in vital technologies being lost.

So What Actually Happened: Or, How and Why do Paleolithic Technologies Vary Through Time and Space?

Paleolithic technologies reflect a vast range of ‘winning' solutions to past biological and cultural challenges. But why so much variation? Why not a fairly homogenous record of just a few useful tool types? The answer is clear. The record is the sum of billions of individual technological decisions, each of which reflects the highly-localized interplay of some or all of the issues touched upon previously (e.g., aspects of biology, culture, raw material availability, the influence of local economic and historical constraints, differing goals, varied tasks, etc.).

For ease of discussion, the record can be simplified by grouping together technologies related in time, space, and degree of sophistication (Table 1). As outlined below, there is general trend towards increased sophistication through time. The trend, however, is not linear. Technological evolution occurred in spurts and stops, with not infrequent retreats, and even the occasional leap and bound (McBrearty & Brooks 2000, Richerson & Boyd 2005, Klein 2009, Powell et al. 2009, Richerson et al. 2009, Lycett & Norton 2010). So what happened? How did the Paleolithic archaeological record actually unfold?

Earlier Stone Age (ESA) / Lower Paleolithic (LP)

East Africa, ~2.6 million years ago, emergence of the archaeological record

The emergence of stone tool technology represents — in hindsight — a momentous step in human evolution (Figure 2). With sharp flakes and simple core tools, early hominins could easily slice through the thickened hides of larger-bodied animals (e.g., antelope and zebra), and readily access nutritious meat, organs, and marrow. In turn, an increased dietary reliance on animal remains is linked to key developments in hominin evolution: brain expansion, dramatic changes in social and behavioral ecologies, and — widely-accepted — the emergence and early evolutionary success of the genus Homo. An increasingly carnivorous diet also led to the enlargement of home ranges and, eventually, to hominin biogeographic expansion out of Africa. Discarded artifacts document the dispersal of toolmaking populations into Asia ~1.9 million years ago.

Africa and Eurasia, ~1.7 million years ago, the slow elaboration of early technologies

The appearance of large cutting tools (LCTs) signals a second major advance in hominin technology (Figure 2). LCTs are effective all-purpose artifacts: Swiss Army knives of sorts, and useful for a wide range of cutting tasks. LCT technology first appears in Africa, and then spreads out across much of southern and western Eurasia. Its extreme rarity in eastern Asia is puzzling, and may reflect the influence of hominin paleodemography — in this case, early populations far too small and/or widely-distributed to maintain a moderate level of technological sophistication (Lycett & Norton 2010). By ~400,000 years ago, the record also reveals two additional technologies of note: sharpened wooden spears, and the habitual use of fire.

Figure 1: Earlier Stone Age (ESA) / Lower Paleolithic (LP) technologies.

(A) Select two stones, each roughly the size of an orange. Smash them together with a somewhat glancing blow and, with a little practice, you may detach a sharp sliver of rock (a flake) from one of the two (now termed the core; the other stone being the hammerstone). Repeat liberally, producing numerous knife-like flakes through the process of flake removal (or knapping). Flakes can be used to slice through meat, fruits, vegetables, roots, or wood. Cores and hammerstones too can be used for heavy-duty processing of plant and animal resources. At an introductory level, these instructions reflect nearly the entirety of the first million years of flaked stone tool production (i.e., the Oldowan). This technology (also termed mode 1) persists to the present as a foundational element of all known lithic toolkits. (B) By ~1.7 million years ago, large cutting tools (LCTs; mode 2) begin to appear in the record. Roughly speaking, LCTs approximate the size and shape of a large, flattened, adult human hand (sometimes substantially larger or smaller; sometimes a bit more oval, u-shaped, or pointy). To fashion LCTs, rough templates are fashioned from large flakes or relatively flat cobbles. These templates are then knapped into fairly standardized forms (e.g., handaxes, picks, or cleavers). LCTs are effective tools for the heavy-duty processing of plant and animal materials. They can also serve as useful cores (i.e., potential sources of simple flakes). The emergence of LCT technology signals the beginning of the Acheulean.

© 2012 Nature Education All rights reserved.

Middle Stone Age (MSA) / Middle Paleolithic (MP)

Africa and Eurasia, ~300,000 years ago, rise of cumulative culture

MSA/MP technologies are associated with the emergence of the most human of adaptations — cumulative culture. In prior periods, technological skills are widely attributed to individual trial-and-error learning, perhaps coupled with a smidgen of social facilitation (i.e., acquiring rudimentary technological knowledge simply by associating with other toolmakers). Highly sophisticated MSA/MP technologies, though, clearly reflect hominins sharing technological know-how with one another on a grand scale (Figure 3). Populations accumulated knowledge over time, tinkered with the past successes of others, and then collectively produced technologies far more sophisticated than what any individual could invent on their own. In short, MSA/MP technologies document the emergence and early evolution of cumulative culture. The importance of this adaptation cannot be overstated. In relatively short order, cumulative culture would produce schools, space travel, as well as the internet and all of its contents (including this article).

With cumulative culture as part of the equation, what transpires in the latter part of the MSA is both predictable and stunning. Feedback loops involving biology, culture, technology, and demography would — when conditions were favorable — lead to the rapid evolution of local innovations. These include the earliest evidence of jewelry, small razor-like geometric flakes, and sophisticated compound tools. Many of these artifacts predate equivalent regional technologies by tens of thousands of years (see below). Then, just as suddenly as they appear, these innovations vanish from their local records for millennia, perhaps again reflecting the delicate interplay between demography, culture, and technology.

Figure 2: Middle Stone Age (MSA) / Middle Paleolithic (MP) technologies.

The MSA/MP introduces a great range of new technologies to the archaeological record: distinct tool types crafted from flakes (e.g., retouched scrapers, stone points, etc.), miniature handaxes, elongated picks, and the widespread adoption of hafting techniques, to name a few. Portions of the African record also provide the occasional glimpse at a few seemingly quite precocious technologies: early instances of shell jewelry, small geometric flakes, and highly sophisticated bone tools. Relative to earlier periods, a greater number of MSA/MP tools types are also somewhat standardized in form. Standardization allows technologies to be tailored to specific tasks, greatly improving task efficiency and/or productivity. It also facilitates the routine production and easy repair of compound tools (i.e., artifacts that are the sum of two or more technologies; e.g., wooden spears + stone spear points + materials for joining the two). When producing lithic artifacts, MSA/MP toolmakers commonly employed prepared core technologies (mode 3). Following this approach, blocks of stone are knapped into predetermined sizes and shapes (e.g., something resembling a turtle shell). One or more flakes of a set morphology are then detached from the core. Some of these flakes may then be modified into more specific tool forms. Lastly, MSA/MP tool forms begin to differentiate by region, sometimes quite dramatically. Some of this variation is likely 'operational' in nature (e.g., populations fine-tuning technologies to best suit local ecological conditions). Other aspects though almost certainly reflect the presence (and stylistic preferences) of distinct culture groups. Specific artifact 'stylings' may reflect the purposeful signaling of group affiliation, the vagaries of historical factors, and/or perhaps even hint at nascent aesthetic concerns.

© 2012 Nature Education All rights reserved.

Later Stone Age (LSA) / Upper Paleolithic (UP)

Africa and Eurasia, ~50,000 years ago, critical mass and expansion; dramatic elaboration of technologies

Starting sporadically ~100,000-70,000 years ago, numerous highly sophisticated technologies begin to flicker through the African archaeological record. These innovations suddenly appear, persist for relatively short periods of time, and then disappear for millennia before suddenly emerging again (Figure 4). It is perhaps akin to repeatedly turning over a stalled engine — one that just fails to start each time.

By ~50,000 years ago, the engine finally ignites. One or more African populations embodied a particular suite of ecological, cultural, and demographic characteristics that facilitated an extraordinary feedback loop (e.g., Powell et al. 2009), one that has been actively maintained to the present day. In turn, ever-improving technologies fuelled population growth, forcing populations to intensify hunting and gathering practices. With local food resources under increased pressures, some groups dispersed in search of new lands. Cultural adaptations (including sophisticated technologies) facilitated the rapid exploitation of an extraordinarily large range of habitats — extending from the desert to the near-arctic, and almost everywhere in between. Over time, superior LSA/UP technologies swept across Africa and Eurasia, eventually making their way as far as Australia and the Americas.

Figure 3: Later Stone Age (LSA) / Upper Paleolithic (UP) technologies.

The LSA/UP reflects a dramatic elaboration of material culture. Building upon technological origins that extend deep into the MSA, toolmakers begin to emphasize the production and use of prismatic blades (mode 4) and geometric microliths (mode 5), two technologies that employ fairly sophisticated prepared core techniques. The former yields a series of elongated cutting edges; the latter returns, in effect, a number of disposable razors. Either could be embedded along the working edge of a spear, harpoon, or knife. The LSA/UP also witnesses a notable increase in non-lithic material culture. Animal bones are, for the first time, routinely utilized as a key raw material in artifact design and manufacture: often coupled with new tool forms/technologies such as fish hooks, harpoon tips, and tiny sewing needles. LSA/UP toolmakers also leave behind some of the earliest unambiguous evidence of symbolic thought and ritualized behaviors: cave paintings, bone flutes, carved figurines, and necklaces made of shells, bones, and teeth. Collectively, LSA/UP technologies reflect the emergence of modern-like capacities to retain and modify useful innovations on a truly large scale. They also document an increased reliance on cultural adaptations. Starting much earlier, but really gathering momentum in the LSA/UP, hominins begin to routinely adapt to complex challenges through real-time shifts in technology and culture (e.g., by inventing spear-throwers or sewn clothing) rather than largely relying on significantly longer-term changes in, say, anatomy (e.g., by evolving slightly longer arms, hairier bodies). This trend toward a greater reliance on cultural solutions increases dramatically through time.

© 2012 Nature Education All rights reserved.

Just the Beginning...

adaptation: ‘Feature of an organism enabling it to survive and reproduce in its natural environment better than if it lacked the feature.' Source: Blackwell, Evolution, 2^nd ed., M. Ridley, 1996.

Acheulean: An Earlier Stone Age/Lower Paleolithic tool industry dating from ~1.7 million years ago to ~120,000 years ago characterized by the production and use of mode 1 & 2 technologies to the exclusion of all others.

anatomy: The biological structure of an organism.

artifact: Material evidence of past human behavior.

behavioral ecology: ‘A heuristic approach based on the expectation that Darwinian fitness (reproductive success) is improved by optimal behavior.' Source: Benjamin/Cummings, Biology, 5^th ed., N. Campbell et al. 1999.

blade: A relatively long thin flake with parallel to sub-parallel sides and a length generally at least twice its width. A hallmark of mode 4 technology, blades are usually detached from prepared cores. In some variants, the resulting core resembles a prism (or cone).

cleaver: A large cutting tool, somewhat flattened in cross-section and u-shaped in outline, with a broad, unworked, transverse cutting edge at the distal end (i.e., at the open end of the ‘u'). The broad transverse working edge contrasts sharply with the pointed tip found at the distal end of handaxes and picks.

core: A rock from which flakes are purposefully detached. Some cores can also be used as heavy-duty tools (i.e., for smashing, chopping, bulk cutting, etc.), especially when dealing with mode 1 & 2 technologies.

culture: Shared learned beliefs, behaviors, customs, practices, etc.

Earlier Stone Age (ESA): A prehistoric Period. An assortment of prehistoric technologies common to some areas of Africa ~2.6 million years ago to ~200,000 years ago, characterized by the production and use of mode 1 and/or mode 2 technologies to the exclusion of all others.

Eurasia: The landmass that incorporates both Europe and Asia.

evolution: ‘Change in the inherited traits of a population through successive generations' Source: NEK 1(10):6.

extant: Refers to ‘living' or ‘existing'.

extinction: Occurs when the death of last individual of a species perishes; it is the end of the organism and the taxa in which it belongs.

feedback loop: A self-reinforcing system in which a change in one parameter leads to changes in one or more others which, in turn, starts the cycle of change anew.

flake: A piece of rock detached from a core through the process of knapping.

forage: To search for food, water, supplies, provisions, etc.

habitat: The physical environment (i.e. the natural resources and physical conditions) of an organism or organisms. Source: © 2010 Nature Education Knowledge.

hafting: To attach one or more tools together (e.g., using animal sinews and a primitive glue to attach [‘haft'] a stone spearhead to a wooden shaft).

hammerstone: A rock used to detach flakes from cores.

handaxe: A large cutting tool, somewhat flattened in cross-section and roughly teardrop-shaped in outline. Handaxes have a series of flake removals along both side margins, creating a pointed tip and a pair of long cutting edges.

harpoon: A spearing tool used in fishing. Harpoons are sharp, often barbed points, commonly carved from bone and affixed to the end of a wooden shaft. In some cases, cordage attached to the harpoon would allow hunters to easily recover their catch and tool.

hominin: Modern humans and our extinct kin that are more closely related to us than to modern chimpanzees)

knap: To purposefully detach a flake and/or shape a core.

large cutting tool (LCT): Large flaked tools, somewhat flattened in cross-section and roughly teardrop-to-u-shaped in outline. Most LCT's have a series of flake removals along the two side margins, creating a pair of long cutting edges. Large cutting tools first appear in the Acheulean and are the hallmark of mode 2 lithic technology. Specific LCT forms include handaxes, picks, and cleavers.

Later Stone Age (LSA): A prehistoric Period. An assortment of prehistoric technologies common to some areas of Africa ~50,000 years ago to recent times, characterized by the production and use of modes 1, 2, 3, 4, & 5 lithic technologies. Mode 5 technologies (geometric microliths) are particularly emphasized. In addition, the LSA is characterized by the widespread use of jewelry, ochre (for paint and glue), bone tools, etc.

lithic: Refers to stone.

Lower Paleolithic (LP): A prehistoric Period. An assortment of prehistoric technologies common to some areas of Eurasia from ~1.9 million years ago to ~20,000 years ago, characterized by the production and use of mode 1 and/or mode 2 technologies to the exclusion of all others.

microliths: Relatively small flakes commonly produced in standardized geometric shapes (trapezoids, crescents, etc.). Microliths were embedded in shafts and handles to create the sharp cutting edges of knives, sickles, arrows, etc.

Middle Paleolithic (MP): A prehistoric Period. An assortment of prehistoric technologies common to some areas of Eurasia and Australia from ~250,000 years ago to less than ~10,000 years ago, characterized by the production and use of modes 1, 2, & 3 technologies to the exclusion of all others. Mode 3 technologies are particularly emphasized.

Middle Stone Age (MSA): A prehistoric Period. An assortment of prehistoric technologies common to some area of Africa from ~300,000 to ~30,000 years ago, characterized by the production and use of modes 1, 2, & 3 technologies to the exclusion of all others. Mode 3 technologies are particularly emphasized. The MSA also contains early examples of mode 4 and 5 technologies.

modes of lithic technology: A hierarchy of basic strategies underlying stone tool production, focusing on the relationship(s) between cores and flakes, as well as the desired end product(s). Modes are categorical and progressive (i.e., they build upon technological advances made in previous modes).

Mode 1: Lithic technology involving the production of relatively unsophisticated non-standardized core and flake forms. Flakes are rarely sharpened or secondarily shaped. Some core forms may serve as heavy-duty cutting or bashing tools.

Mode 2: Lithic technology involving the production of large cutting tools (LCTs) through the purposeful shaping/knapping of stone. While LCTs primarily serve as heavy-duty cutting implements, they may also serve as basic core forms from which useable flakes are knapped.

Mode 3: Lithic technology involving the production of relatively standardized flake forms through the planned prior shaping of cores (i.e., through the use of ‘prepared cores'). Once obtained, targeted flakes can either be used ‘as-is', or be modified into more specific ‘flake tool' forms (e.g., a particular type of scraper, point, etc.). Prepared cores are generally not used for tasks other than flake production.

Mode 4: Lithic technology involving the production of relatively standardized blade forms through the planned prior shaping of cores (i.e., through the use of ‘prepared cores'). Once obtained, blades can either be used ‘as is', or be modified into more specific tool forms. Many blades are eventually incorporated into compound tools (e.g., knives, etc.). Prepared cores are generally not used for tasks other than flake production.

Mode 5: Lithic technology involving the production of relatively standardized microlith forms through the planned prior shaping of cores (i.e., through the use of ‘prepared cores'). Once obtained, microliths can either be used ‘as is', or be modified into more specific tool forms. Many microliths are eventually incorporated into compound tools: knives, spears, arrows, sickles, etc. Prepared cores are generally not used for tasks other than flake production.

morphology: Refers to form or structure.

Oldowan: An Earlier Stone Age/Lower Paleolithic tool industry characterized by the production and use of mode 1 technology to the exclusion of all others. The Oldowan is replaced by the Acheulean industry (with mode 2 technology) ~1.7 million-years-ago.

paleobiology: The study of past biological systems.

paleodemography: The study of past population parameters (number of individuals, age structure, patterns of migration, density per unit area, etc.).

pick (artifact): A large cutting tool, somewhat flattened in cross-section and both fairly narrow and triangular in outline. Picks have a series of flake removals along both side margins, creating a pointed tip and pair of long cutting edges.

retouch: Purposeful knapping along the edge of a tool, usually to produce a sharper working edge.

scraper: A tool form produced by retouching a flake into a relatively specific shape optimal for scraping flesh from hides, woodworking, etc.

symbolic thought: The ability to manipulate and use abstract concepts (e.g., words, numbers, symbols, gestures, etc.) to represent events, people, places, or things — including other abstract ideas (love, freedom, etc.).