First exhaustive analysis of use-wear traces on basalt tools from Olduvai

First exhaustive analysis of use-wear traces on basalt tools from Olduvai

The CENIEH leads an experimental study of the possible uses for tools made from basalts at Olduvai Gorge (Tanzania), by analyzing the relationships between the petrological characteristics of this raw material and the formation of use-wear traces
basalt tools Olduvai
Beta vulgaris processing during the experimental basalt program/P. Bello-Alonso

The Centro Nacional de Investigación sobre la Evolución humana (CENIEH) has participated in an experimental study published recently in the journal Archaeological and Anthropological Sciences, on the possible uses of tools fashioned from basalts, volcanic rocks that are highly abundant at the Olduvai Gorge sites in Tanzania, through the first exhaustive analysis of the relationships between the petrological characteristics of this raw material and the formation of use-wear traces.

In addition to providing elements of great significance for interpreting human behavior at Olduvai Gorge, the results of this research led by the archaeologist Patricia Bello-Alonso furnish a model which will enable comparative studies for lithic industry assemblages in volcanic rocks from different archaeological and geological contexts to be conducted.

“The results we have obtained are a fundamental resource for analyzing the ways stone tools were used at the archaeological sites located in Beds I and II, in general, and at the Thiongo Korongo (TK) site in particular as, in this area, volcanic rocks are one of the key raw materials for the technological and, therefore, evolutionary development of the different hominin groups that occupied Olduvai more than two million years ago”, explains Bello-Alonso.

Reference Collection

The main objective of the research, in which the Museo de Ciencia Naturales and the Instituto de Evolución Humana en África in Madrid also participated, was to determine how traces are formed in basalts at both the macro and micro scales, to enable their use to be identified. To do so, non-retouched flakes were employed and a wide variety of organic materials was worked upon: animal carcasses, tubers, wood, grass, cane and fresh bone.

“Carrying out these operations has allowed us to compile an experimental reference collection for greater understanding of the role played by the internal and chemical structure of basalts in the formation and development of use-wear traces”, she adds.

This multidisciplinary study, financed by the Ministerio de Ciencia, Innovación y Universidades (HAR2013-45246-C3-2-P and HAR2017-82463-C4-2-P), under the auspices of The Olduvai Paleonthropology and Paleoecology Project (TOPPP) on the Acheulean site of TK, led by the researchers Joaquín Panera and Manuel Santonja, was conducted at the Prehistoric Technology and Archaeology Laboratory of the CENIEH and the Emiliano Aguirre camp, at Olduvai Gorge itself.

Full bibliographic information

Bello-Alonso, P., Rios-Garaizar, J., Panera, J., Martín-Perea, D.M., Rubio-Jara, S., Pérez-González, A., Rojas-Mendoza, R., Domínguez-Rodrigo, M., Baquedano, E., y Santonja, M. Experimental approaches to the development of use-wear traces on volcanic rocks: basalts. Archaeol Anthropol Sci 12, 128 (2020). https://doi.org/10.1007/s12520-020-01058-6.
Press release from CENIEH on the basalt tools from Olduvai.

El Provencio

First exhaustive study of the Paleolithic site of El Provencio

First exhaustive study of the Paleolithic site of El Provencio

The CENIEH researcher Davinia Moreno has co-led the publication of a paper on this Paleolithic site in the province of Cuenca, whose age, according to the ESR dating technique, is 830,000 years.
El Provencio
El Provencio site. Credits: Santiago David Domínguez-Solera, ARES arqueología

The researcher Davinia Moreno, a geochronologist at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), is the co-leader of a paper published in the journal Quaternary International about El Provencio, in which the first exhaustive study of this Paleolithic site in the province of Cuenca, situated in the La Mancha plain on the banks of the Záncara River, is conducted.

The geochronological analysis carried out at the CENIEH, applying the techniques of Electron Spin Resonance (ESR) and Optically Stimulated Luminescence (OSL) has provided the first numerical datings in this region. The most recent and most ancient levels of the archaeological sequence were dated, yielding ages of 41,000 (OSL) and 830,000 years (ESR).

The rich archaeo-paleontological record of El Provencio exhibits stone tools worked in flint and quartzite catalogued as Modes 1, 2 and 3 (Oldowan, Acheulean and Mousterian), as well as bone remains from species characteristic of the Pleistocene such as horses, bisons and mammoths.

This study suggests that, over the last 800,000 years, groups of hunter-gatherers occupied this territory, undertaking a variety of activities recurrently and continuously, and it undercuts theories of a discontinuity in the center of the Iberian Peninsula and those contending that population was more intensive on the coast than in the interior.

Research and outreach project

The research work at El Provencio is part of a much larger project that got under way in 2013 and which, at the moment, covers dozens of locations throughout the province of Cuenca. This project, directed by Santiago David Domínguez-Solera, lead author of this study, through the company ARES (Arqueología y Patrimonio Cultural) is being conducted in close collaboration with the Junta de Comunidades de Castilla-La Mancha, the Diputación de Cuenca and the Ayuntamiento de El Provencio.

From the outset, this project has placed special importance on outreach for its scientific results: a classroom for schoolchildren and visitors has been set up, and documentary reportage, exhibitions and university courses (Universidad Internacional Menéndez Pelayo) in the municipality of El Provencio itself have been produced.

"As of several years ago, we have been opening up a window onto the prehistoric past, aligning it with the three natural zones making up what is today the province of Cuenca; La Mancha, Sierra and Alcarria, each with its particular features. This window offers a glimpse of an area little studied or overlooked up to now, and therefore unknown to science”, declares Domínguez-Solera.

Press release from CENIEH

The African affinities of the southwestern European Acheulean

A study highlights the African affinities of the southwestern European Acheulean

The CENIEH is the co-leader of a paper published in the Journal of Paleolithic Archaeology which presents a synthesis of human occupation in the Iberian Peninsula Atlantic margin during the Early and Middle Paleolithic
African Acheulean
Porto Maior site (As Neves, Pontevedra). Credits: Eduardo Méndez

The Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) is the co-leader of a study published this week in the Journal of Paleolithic Archaeology which presents a synthesis of human occupation in the Iberian Peninsula Atlantic margin during the Early and Middle Paleolithic, and highlights the African affinities of Acheulean industry in southwestern Europe.

Over recent years, a team whose members include the CENIEH archaeologist Manuel Santonja, and Eduardo Méndez, leading author of the study trained at the CENIEH, has excavated and interpreted important archaeological sites on the banks of the Miño River, on both the Portuguese and Spanish shores, with singular Acheulean and Mousterian assemblages.

The chronology attributed to these sites, the second half of the Middle Pleistocene and the first part of the Late Pleistocene (between 50,000 and 400,000 years ago), and the characteristics of the knapped utensils recovered allow close parallels to be drawn with other regions of the Iberian Peninsula, and rule out any kind of time mismatch in these stages in the northwestern area, as had been proposed earlier.

Some of the sites excavated, and in particular the Acheulean one at Porto Maior (As Neves, Pontevedra), have produced unusual assemblages of large utensils, handaxes and cleavers, which make a decisive contribution to underlining the African affinities of that industry in the Iberian Peninsula and southwestern Europe, in contrast to Acheulean assemblages identified in the northernmost areas of the continent, where the distinctive technological features of the African Acheulean arrive less crisply defined.

 

Full bibliographic information

Méndez-Quintas, E., Santonja, M., Arnold, L. J., Cunha-Ribeiro, J. P., Xavier da Silva, P., Demuro, M., Duval, M., Gomes, A., Meireles, J., Monteiro-Rodrigues, S., & Pérez-González, A. (2020). The Acheulean technocomplex of the Iberian Atlantic margin as an example of technology continuity through the Middle Pleistocene. Journal of Paleolithic Archaeology (0). doi: 10.1007/s41982-020-00057-2.
Press release from CENIEH

Neandertals underwater clam shells

Neandertals went underwater to collect clam shells and pumice for their tools

Neandertals went underwater for their tools

Neandertals collected clam shells and pumice from coastal waters to use as tools

Neandertals underwater clam shells
General morphology of retouched shell tools, Figs C-L are from the Pigorini Museum. Credit: Villa et al., 2020 CC-BY

Neandertals collected clam shells and volcanic rock from the beach and coastal waters of Italy during the Middle Paleolithic, according to a study published January 15, 2020 in the open-access journal PLOS ONE by Paola Villa of the University of Colorado and colleagues.

Neandertals are known to have used tools, but the extent to which they were able to exploit coastal resources has been questioned. In this study, Villa and colleagues explored artifacts from the Neandertal archaeological cave site of Grotta dei Moscerini in Italy, one of two Neandertal sites in the country with an abundance of hand-modified clam shells, dating back to around 100,000 years ago.

The authors examined 171 modified shells, most of which had be retouched to be used as scrapers. All of these shells belonged to the Mediterranean smooth clam species Callista chione. Based on the state of preservation of the shells, including shell damage and encrustation on the shells by marine organisms, the authors inferred that nearly a quarter of the shells had been collected underwater from the sea floor, as live animals, as opposed to being washed up on the beach. In the same cave sediments, the authors also found abundant pumice stones likely used as abrading tools, which apparently drifted via sea currents from erupting volcanoes in the Gulf of Naples (70km south) onto the Moscerini beach, where they were collected by Neandertals.

These findings join a growing list of evidence that Neandertals in Western Europe were in the practice of wading or diving into coastal waters to collect resources long before Homo sapiens brought these habits to the region. The authors also note that shell tools were abundant in sediment layers that had few stone tools, suggesting Neandertals might have turned to making shell tools during times where more typical stone materials were scarce (though it's also possible that clam shells were used because they have a thin and sharp cutting edge, which can be maintained through re-sharpening, unlike flint tools).

The authors add: "The cave opens on a beach. It has a large assemblage of 171 tools made on shells collected on the beach or gathered directly from the sea floor as live animals by skin diving Neandertals. Skin diving for shells or fresh water fishing in low waters was a common activity of Neandertals, according to data from other sites and from an anatomical study published by E. Trinkaus. Neandertals also collected pumices erupted from volcanoes in the gulf of Naples and transported by sea to the beach."

###

Citation: Villa P, Soriano S, Pollarolo L, Smriglio C, Gaeta M, D'Orazio M, et al. (2020) Neandertals on the beach: Use of marine resources at Grotta dei Moscerini (Latium, Italy). PLoS ONE 15(1): e0226690. https://doi.org/10.1371/journal.pone.0226690

Funding: National Science Foundation Grant 1118143, BCS Archaeology, to PV (PI) and SS (co-PI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

 

Press release from the Public Library of Science

Beach-combing Neanderthals dove for shells

Did Neanderthals wear swimsuits? Probably not. But a new study suggests that some of these ancient humans might have spent a lot of time at the beach. They may even have dived into the cool waters of the Mediterranean Sea to gather clam shells.

The findings come from Grotta dei Moscerini, a picturesque cave that sits just 10 feet above a beach in what is today the Latium region of central Italy.

In 1949, archaeologists working at the site dug up some unusual artifacts: dozens of seashells that Neanderthals had picked up, then shaped into sharp tools roughly 90,000 years ago.

Now, a team led by Paola Villa of the University of Colorado Boulder has uncovered new secrets from those decades-old discoveries. In research published today (editor's note: January 15) in the journal PLOS ONE, she and her colleagues report that the Neanderthals didn't just collect shells that were lying out on the beach. They may have actually held their breath and went diving for the perfect shells to meet their needs.

Villa, an adjoint curator in the CU Museum of Natural History, said the results show that Neanderthals may have had a much closer connection to the sea than many scientists thought.

"The fact they were exploiting marine resources was something that was known," Villa said. "But until recently, no one really paid much attention to it."

Cave discoveries

When archaeologists first found shell tools in Grotta dei Moscerini, it came as a surprise. While Neanderthals are well-known for crafting spear tips out of stone, few examples exist of them turning shells into tools.

But the find wasn't a fluke. The 1949 excavation of the cave unearthed 171 such tools, all valves from shell belonging to a local species of mollusk called the smooth clam (Callista chione). Villa explained that the ancient humans used stone hammers to chip away at these shells, forming cutting edges that would have stayed thin and sharp for a long time.

"No matter how many times you retouch a clam shell, its cutting edge will remain very thin and sharp," she said.

But did the Neanderthals, like many beachgoers today, simply collect these shells while taking a stroll along the sand?

To find out, Villa and her colleagues took a closer look at those tools. In the process, they found something they weren't expecting. Nearly three-quarters of the Moscerini shell tools had opaque and slightly abraded exteriors, as if they had been sanded down over time. That's what you'd expect to see, Villa said, on shells that had washed up on a sandy beach.

The rest of the shells had a shiny, smooth exterior.

Those shells, which also tended to be a little bit bigger, had to have been plucked directly from the seafloor as live animals.

"It's quite possible that the Neanderthals were collecting shells as far down as 2 to 4 meters," Villa said. "Of course, they did not have scuba equipment."

Researchers also turned up a large number of pumice stones from the cave that Neanderthals had collected and may have used as abrading tools. The stones, Villa and her colleagues determined, washed onto the Moscerini beach from volcanic eruptions that occurred more than 40 miles to the south.

Going for a dip

She's not alone in painting a picture of beach-loving Neanderthals.

In an earlier study, for example, a team led by anthropologist Erik Trinkaus identified bony growths on the ears of a few Neanderthal skeletons. These features, called "swimmer's ear," can be found in people who practice aquatic sports today.

For Villa, the findings are yet more proof that Neanderthals were just as flexible and creative as their human relatives when it came to eking out a living--a strong contrast to their representation in popular culture as a crude cavemen who lived by hunting or scavenging mammoths.

"People are beginning to understand that Neanderthals didn't just hunt large mammals," Villa said. "They also did things like freshwater fishing and even skin diving."

Other coauthors on the new study included researchers from the French National Centre for Scientific Research, the University of Geneva, Roma Tre University, Sapienza University of Rome and the University of Pisa.

Press release from the University of Colorado at Boulder

 

 

 

 

 


Citi exhibition Arctic: culture and climate

"Arctic: culture and climate", an exhibition on the history of the Arctic people

British Museum announces major exhibition on the Arctic
The Citi exhibition Arctic: culture and climate

28 May – 23 August 2020
Sainsbury Exhibitions Gallery

Lead supporter Citi
Supported by
Julie and Stephen Fitzgerald
AKO Foundation

There's Another One

In May 2020 the British Museum will open the first major exhibition on the history of the Arctic and its indigenous peoples, through the lens of climate change and weather. The Arctic has been home to resilient communities for nearly 30,000 years, cultures that have lived with the opportunities and challenges of one of the most dramatic and dynamic environments on the planet. Today climate change is transforming the Arctic at the fastest rate in human history. The Citi exhibition Arctic: culture and climate is the first to look at the circumpolar region through the eyes of contemporary Arctic communities, revealing how Arctic peoples have adapted to climate variability in the past and addresses the global issue of changing climate through their stories in a transforming world.

Citi exhibition Arctic: culture and climate
Arctic Foliage wall hanging

Bringing together the largest and most diverse circumpolar collection ever displayed in the UK, including objects from the British Museum’s world-class Arctic collection and international lenders and commissions, this exhibition will reveal a wealth of artistic expression and ecological knowledge, from the past right up to the present day. From rare 28,000 year old archaeological finds excavated from the thawing ground in Siberia, unique tools and clothing adapted for survival, artworks reflecting the respectful relationship between Arctic people and the natural world, to stunning photography of contemporary daily life, the exhibition will show the great diversity of cultures and ingenuity of communities responding to dramatic changes in seasonal weather and human-caused climate change.

Walrus ivory needles, Yana-site, Russia

The Arctic Circle is the most northern region in the world encompassing the area of midnight sun in summer and the polar night in winter that covers 4% of the Earth. It is home to 4 million people including 400,000 indigenous peoples belonging to one or more of 40 different ethnic groups with distinct languages and dialects. Most of the Arctic’s indigenous inhabitants rely on hunting, fishing and reindeer herding. These subsistence resources are supplemented by employment in industries such as government infrastructures, energy, commercial fishing and tourism.

Arctic peoples have traded and engaged across the Circumpolar North for millennia. From Russia, Greenland, Canada and the USA to the Scandinavian nations, the peoples of the region have thrived within this ever-changing and evolving landscape. Scientists predict that the Arctic will be ice-free in 80 years, which will bring dramatic and profound change to the people that live there and will affect us all.

Citi exhibition Arctic: culture and climate
Sledge

Twyla Thurmond, tribal coordinator, from Shishmaref, Alaska says “Shishmaref and other Alaska Native communities are demonstrating how people can stay strong and unified in their search for answers to climate change, the most challenging problem of the 21st century.”

The exhibition will feature many highlight objects from across the circumpolar region, including an 8-piece Igloolik winter costume made of caribou (wild reindeer) fur, illustrating the relationship between humans and animals in the Arctic. The hunted animal provides food for the community as well as clothing, perfectly adapted to help humans survive the extreme cold. All available natural materials are put to use. A delicate and unique household bag from western Alaska, crafted from tanned salmon skin, demonstrates the beautiful properties that emerge from fishskin when skilled practitioners work and expose material to particular weather conditions.

Icon into mask

Over the past 300 years, Arctic peoples have faced dramatic social, economic, and political changes as a result of European and Russian exploration to the region, quests for the Northwest Passage, and the global fur trade. A key object from this period is the Inughuit (Greenlandic) sled made from narwhal and caribou bone and pieces of driftwood. It was traded to Sir John Ross on his 1818 expedition, marking the first encounter between Inughuit and Europeans. Arctic peoples’ responses to the establishment of colonial governments and state-sponsored religions in the Arctic will feature, including a bronze carved Evenki spirit mask that was made from a 17th century Russian Orthodox icon. Today, Arctic peoples are transforming traditional heritage to meet contemporary needs and safeguard their culture. From performances adapted from ritual practices to commercial artwork inspired by storytelling and material traditions.

Citi exhibition Arctic: culture and climate
Inukshuk

Stunning contemporary photography of the Arctic landscape and local communities will form part of the immersive exhibition design. There will be a number of new artworks commissioned for the exhibition. These include a limestone Inuksuk, an iconic Arctic monument of stacked stones used to mark productive harvesting locations or to assist in navigation, built by Piita Irniq, from the Kivalliq Region of Nunavut, Canada. A new installation from the art collective Embassy of Imagination will present traditional clothing made from Japanese paper and printmaking by Inuit youth in Kinngait (Cape Dorset) and Puvirnitug, Nunavut, Canada.

Citi exhibition Arctic: culture and climate
Sami hat

The Citi exhibition Arctic: culture and climate will tell inspirational stories of human achievement while celebrating the region’s natural beauty. It will encourage debate about the future of this globally significant landscape in the light of the global climate change. Arctic peoples have faced different kinds of change, developing strategies and tools to mitigate the disruptive effects of social and environmental change from which we can all learn.

Lead supporter Citi

Supported by Julie and Stephen Fitzgerald, and AKO Foundation

Amber Lincoln, Curator, Americas Section, British Museum, said ‘Through the generosity of indigenous Arctic people and Arctic scholars, this exhibition weaves together compelling stories, objects and landscapes of the Circumpolar North, at a time when the Arctic is changing before our very eyes.’

Hartwig FischerDirector of the British Museum, said ‘The Citi exhibition Arctic: culture and climate is a bold and ambitious exhibition that reflects the expanding vision of the British Museum. The show directly addresses the essential question of how humans can live with the impacts of extreme weather. The future and past come together in the present, united by the shared experiences of Arctic peoples. I would like to thank Citi, whose on-going support has allowed the Museum to realise this ground-breaking exhibition.’

James Bardrick, Citi Country Officer, United Kingdom says: “As a global bank, we play an essential role in financing a sustainable economy and supporting indigenous peoples’ rights. We are particularly proud to partner with the British Museum for the forthcoming Arctic: culture and climate exhibition that sheds light on the formidable artistic expression and ecological knowledge of the Arctic populations. We are committed to financing and facilitating clean energy, infrastructure and technology projects that support environmental solutions and reduce the impacts of climate change, on rich and diverse communities such as those that inhabit the circumpolar Arctic.”

Citi exhibition Arctic: culture and climate
Umiaq and north wind during spring whaling by Kiliii Yuyan

If you want to read more about Arctic: culture and climate, follow the British Museum blog at blog.britishmuseum.org

 

Press release from the British Museum

Pictures courtesy of the British Museum


Tollense Vallery Bronze Age battlefield

A warrior on a unique Bronze Age battlefield site in the Tollense Valley

Lost in Combat? Researchers discover belongings of a warrior on unique Bronze Age battlefield site

Tollense Vallery Bronze Age battlefield
This collection of objects was found by divers in the Tollense river and is probably the contents of a personal pouch of a warrior who died 3,300 years ago on the battlefield. Credit: Volker Minkus

Recent archaeological investigations in the Tollense Valley led by the University of Göttingen, the State Agency for Cultural Heritage in Mecklenburg-Vorpommern and the University of Greifswald have unearthed a collection of 31 unusual objects. Researchers believe this is the personal equipment of a Bronze Age warrior who died on the battlefield 3,300 years ago.  This unique find was discovered by a diving team headed by Dr Joachim Krüger, from the University of Greifswald, and seems to have been protected in the river from the looting, which inevitably followed fighting.  The study was published in Antiquity.

Tollense Vallery Bronze Age battlefield
These are the battlefield remains from the layer where objects were found at the site near the Tollense river in Weltzin. Credit: Stefan Sauer

The archaeological records of the European Bronze Age are dominated by settlement finds, hoards and evidence of funeral sites.  However, the site at the river Tollense in Northern Germany is very different and provides for the first time in Europe the evidence of a prehistoric battlefield.  Over 12,000 pieces of human bone have already been recovered from the valley and osteoanthropologist Ute Brinker, from the State Agency has identified more than 140 individuals – young adult males in good physical condition. Their bones showed signs of recent trauma – the result of close and long-range weapons – and healed lesions, which probably indicate they were accustomed to combat. Isotopic results suggested that at least some of the group were not from the local area, but until now, it was not clear how far they travelled.

 

The discovery of a new set of artefacts from the remains of battle provides important new clues. The divers could document a number of Bronze finds in their original position on the river ground, among them a decorated belt box, three dress pins and also arrow heads. Surprisingly they also found 31 objects (250g) tightly packed together, suggesting they were in a container made of wood or cloth that has since rotted away. The items include a bronze tool with a birch handle, a knife, a chisel and fragments of bronze. Radiocarbon dating of the collection of objects demonstrates that the finds belong to the battlefield layer and they were probably the personal equipment of one of the victims. The finds were studied in a Master’s thesis by Tobias Uhlig and the new results make it increasingly clear that there was a massive violent conflict in the older Nordic Bronze Age (2000–1200 BC). In fact, recent evidence suggests that it is likely to have been on a large scale, clearly stretching beyond regional borders.

Tollense Vallery Bronze Age battlefield
This is a human skull found in the Tollense valley with fatal trauma caused by a Bronze arrowhead. Credit: Volker Minkus

Professor Thomas Terberger, from the Department of Pre- and Early History at the University of Göttingen, says, “This is the first discovery of personal belongings on a battlefield and it provides insights into the equipment of a warrior. The fragmented bronze was probably used as a form of early currency. The discovery of a new set of artefacts also provides us with clues about the origins of the men who fought in this battle and there is increasing evidence that at least some of the warriors originated in southern Central Europe.”

 

Original publication: Tobias Uhlig et al. Lost in combat? A scrap metal find from the Bronze Age battlefield site at Tollense (2019), Antiquity. DOI: 10.15184/aqy.2019.137

 

Press release (No. 207 - 15.10.2019) from the University of Göttingen / DE


From Stone Age chips to microchips: How tiny tools may have made us human

From Stone Age chips to microchips: How tiny tools may have made us human

The technology of miniaturization set hominins apart from other primates

The iconic, tear-drop shaped hand axe, which filled a human palm, required a large toolkit to produce (left), in contrast to a toolkit for tiny flakes. Credit: Emory University

Anthropologists have long made the case that tool-making is one of the key behaviors that separated our human ancestors from other primates. A new paper, however, argues that it was not tool-making that set hominins apart -- it was the miniaturization of tools.

Just as tiny transistors transformed telecommunications a few decades ago, and scientists are now challenged to make them even smaller, our Stone Age ancestors felt the urge to make tiny tools. "It's a need that we've been perennially faced with and driven by," says Justin Pargeter, an anthropologist at Emory University and lead author of the paper. "Miniaturization is the thing that we do."

Stone Age miniaturization stone tools prehistory
Going small may have helped some humans survive the last period of rapid climate change, 17,000 years ago, says Emory anthropologist Justin Pargeter. Credit: Emory University

The journal Evolutionary Anthropology is publishing the paper -- the first comprehensive overview of prehistoric tool miniaturization. It proposes that miniaturization is a central tendency in hominin technologies going back at least 2.6 million years.

"When other apes used stone tools, they chose to go big and stayed in the forests where they evolved," says co-author John Shea, professor of anthropology at Stony Brook University. "Hominins chose to go small, went everywhere, and transformed otherwise hostile habitats to suit our changing needs."

The paper reviews how stone flakes less than an inch in length -- used for piercing, cutting and scraping -- pop up in the archeological record at sites on every continent, going back to some of the earliest known stone tool assemblages. These small stone flakes, Pargeter says, were like the disposable razor blades or paperclips of today -- pervasive, easy to make and easily replaced.

He identifies three inflection points for miniaturization in hominin evolution. The first spike occurred around two million years ago, driven by our ancestors' increasing dependence on stone flakes in place of nails and teeth for cutting, slicing and piercing tasks. A second spike occurred sometime after 100,000 years ago with the development of high-speed weaponry, such as the bow and arrow, which required light-weight stone inserts. A third spike in miniaturization occurred about 17,000 years ago. The last Ice Age was ending, forcing some humans to adapt to rapid climate change, rising sea levels and increased population densities. These changes increased the need to conserve resources, including the rocks and minerals needed to make tools.

A native of South Africa, Pargeter co-directs field work in that country along its rugged and remote Indian Ocean coastline and nearby inland mountains. He is also a post-doctoral fellow in Emory University's Center for Mind, Brain and Culture and the Department of Anthropology's Paleolithic Technology Laboratory. The lab members actually make stone tools to better understand how our ancestors learned these skills, and how that process shaped our evolution. The lab's director, Dietrich Stout, focuses on hand axes, dating back more than 500,000 years. These larger tools are considered a turning point in human biological and cognitive evolution, due to the complexity involved in making them.

Pargeter's work on tiny tools adds another facet to the investigation of human evolution. "He's exploring what may have led to the compulsion to produce these tiny instruments -- essentially the relationship between the tools and the human body, brain and the probable uses of the tools," Stout says.

When looking for a PhD thesis topic, Pargeter first focused on collections of larger implements, considered typical of the Stone Age tool kit. He pored over artifacts from a South African site called Boomplaas that were being held in storage at the Iziko Museum in Cape Town. As he rummaged through a bag labelled as waste -- containing small flakes thought to be left over from making larger tools -- something caught his eye. A sliver of crystal quartz looked like it had been shaped using a highly technical method called pressure flaking.

"It was diminutive, about the size of a small raisin, and weighed less than half a penny," he recalls. "You could literally blow it off your finger."

Pargeter examined the flake under a magnifying glass. He noticed it had a distinctive, stair-step fracture on its tip that previous experimental research showed to be associated with damage caused in hunting.

"It suddenly occurred to me that archeologists may have missed a major component of our stone tool record," Pargeter says. "In our desire to make 'big' discoveries we may have overlooked tiny, but important, details. A whole technology could lay hidden behind our methods, relegated to bags considered waste material."

So how to interpret the use of a tool so tiny that you could easily blow it off your finger?

Pargeter began thinking of this question in terms of the age of the flake -- about 17,000 years -- and the environment at the time. The last Ice Age was ending and massive melting of ice at the poles caused the global sea-level to rise. In parts of South Africa, the rising oceans swallowed an area the size of Ireland. As the coastal marshes and grasslands disappeared -- along with much of the game and aquatic life -- the hunter-gatherers living there fled inland to sites like Boomplaas, currently located about 80 kilometers inland. The mountains around Boomplaas provided permanent springs and other dependable freshwater sources.

The climate, however, was less predictable, with sudden shifts in temperature and rainfall. Vegetation was shifting dramatically, temperatures were rising and large mammals were increasingly scarce. Archaeology from Boomplaas shows that people ate small game like hares and tortoises. These small animals would have been easy to catch, but they provided limited nutritional packages.

"These are low-reward food sources, indicating a foraging stress signal," Pargeter says. "Boomplaas might have even served as a type of refugee camp, with groups of hunter-gatherers moving away from the coast, trying to survive in marginal environments as resources rapidly depleted and climate change ratcheted up."

Arrow points a little less than an inch across were already in the archaeological literature, but the Boomplaas crystal quartz flake was half that size. In order to bring down an animal, Pargeter hypothesized, the Boomplaas flake would need poison on its tip -- derived either from plants or insects -- and a high-speed delivery system, such as a bow and arrow.

The tiny crystal flake, from a site in South Africa called Boomplaas, that sparked Justin Pargeter to investigate Stone Age miniaturization. Credit: Justin Pargeter

Pargeter used his own extensive knowledge of prehistoric tool-making and archaeology to hypothesize that the tiny flake could have been hafted, using a plant-based resin, onto a link shaft, also likely made of a plant-based material, such as a reed. That link shaft, about the length of a finger, would in turn fit onto a light arrow shaft.

"The link shaft goes into the animal, sacrificing the small blade, but the arrow shaft pops out so you can retain this more costly component," he says. "Our ancestors were masters of aerodynamics and acted like engineers, rather than what we think of as 'cave people.' They built redundancy into their technological systems, allowing them to easily repair their tools and to reduce the impact of errors."

Our ancestors were also connoisseurs of the type of fine-grained rocks needed for tool-making.

Supplies of such vital toolmaking raw materials, however, were likely diminished as the rising oceans consumed land and people became more crowded together, driving them to more carefully conserve what they could find on the landscape.

As paleoanthropologists are faced with more than three million years of hominin "stuff," one of the perennial questions they keep seeking to answer is, what makes us humans unique? "We've typically said that tool use makes us human, but that's kind of buckled under," Pargeter says, as evidence of tool use by other animals accumulates.

Macaques, for example, use rocks to smash apart oysters. Chimpanzees use rocks as hammers and anvils to crack nuts and they modify sticks to dig and fish for termites. These tools, however, are large. "The hands of other primates are not evolved for repeated fine manipulation in high-force tasks," Pargeter says. "We've evolved a unique precision grip that ratchets up our ability for miniaturized technology."

Humans are also the masters of dispersing into novel environments, unlike other primates that remained in the landscapes of their ancestors. "Smaller tools are the choice of technology for a mobile, dispersing population," Pargeter says. "When Homo sapiens left Africa they weren't carrying bulky hand axes, but bows and arrows and smaller stone implements."

 

Press release from Emory Health Sciences


Proofs of parallel evolution between cognition, tool development, and social complexity

Proofs of parallel evolution between cognition, tool development, and social complexity

A study analyzes the selective attention processes that determine how we explore and interact with our environment

Proofs of parallel evolution between cognition, tool development, and social complexity Galician ceramics Iberia prehistory
Main ceramics analyzed in the experiments and heatmap of the visual fixations in each one of them. The images are organized, from left to right, in chronological order from oldest to most recent. Following time, the fixations direction changes from horizontal to vertical. Credit: CSIC

Researchers examined the visual response of 113 individuals when observing prehistoric ceramics belonging to different styles and societies. The ceramics analysed cover 4.000 years (from 4.000 B.C. to the change of era) of Galician prehistory (north-west Iberia), and are representative of ceramic styles, such as bell-beaker pottery, found throughout Europe. The results indicate that the visual behaviour follows the same evolutionary trends as those that drive the evolution of the complex societies that built these archaeological materialities.

"We hypothesised that culture and social life influence cognition in a highly stereotyped fashion. Eye movements are the most objective proof of a parallel evolution between the cognitive process, material development and changes in social complexity", explains CSIC researcher Felipe Criado-Boado, from the Institute of Heritage Sciences, in Santiago de Compostela. This study is part of the field of neuroarchaeology, a new scientific field that combines neuroscience with human palaeontology, archaeology, and other social and human sciences.

"The visual prominence of each ceramic style produces a distinct visual response. Prehistoric ceramics comprise an important part of the material world that surrounded the individuals of that time. This is why an analysis of this kind is not only feasible, but also provides very significant results", adds Criado-Boado.

Luis M. Martínez, a researcher from the Institute of Neurosciences, in Alicante, explains that, "in our brain there are neural circuits, or maps, that represent our personal and peripersonal space. These circuits determine the way in which we relate socially, and also with the world around us. With experiments of this kind, we are demonstrating that these representations are modified by the use and making of tools and other cultural artefacts; what we are discovering is that they are quickly incorporated into these neural maps, becoming part of our body schema as if they were an extension of it. These experiments unequivocally demonstrate that there is a very close interaction between cultural changes and brain plasticity, which provides a new perspective on how the brain governs for the transmission of cultural values, beliefs and customs".

The results of this research indicate that the human visual system actively internalises the object it observes, which would demonstrate that there is a perceptual engagement between the observers and the material structures in their environment. "This is why perception cannot be separated from form. Seen from this perspective, it could be proposed that the shape of objects (pottery, in this case) and the pattern of visual exploration they produce have changed over history, and are connected with behaviour in the same way as they are with the social realm, including social complexity," says Criado-Boado.

Another of the conclusions of this study is that technology is an important factor in the mental aspects of human life. This offers a new perspective that helps to explain the processes of innovation and technological change that take place in all historical periods, including the present day. "It is believed that by 2020 there will be 100 billion sensors around the world capturing information of all kinds and processing it digitally, all connected to each other and functioning like an enormous human mind. If this prediction is fulfilled, research in the field of cognitive processes and material culture throughout history may be useful for the future, since it can show how humans rely on images that symmetrically help them to shape a collective consciousness of the world", concludes the researcher.

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