Wednesday, April 15, 2015

Complex cognition shaped the Stone Age hand axe


The ability to make a Lower Paleolithic hand axe depends on complex cognitive control by the prefrontal cortex, including the "central executive" function of working memory, a new study finds.

PLOS ONE published the results, which knock another chip off theories that Stone Age hand axes are simple tools that don't involve higher-order executive function of the brain.

"For the first time, we've showed a relationship between the degree of prefrontal brain activity, the ability to make technological judgments, and success in actually making stone tools," says Dietrich Stout, an experimental archeologist at Emory University and the leader of the study. "The findings are relevant to ongoing debates about the origins of modern human cognition, and the role of technological and social complexity in brain evolution across species."

The skill of making a prehistoric hand axe is "more complicated and nuanced than many people realize," Stout says. "It's not just a bunch of ape-men banging rocks together. We should have respect for Stone Age tool makers."

The study's co-authors include Bruce Bradley of the University of Exeter in England, Thierry Chaminade of Aix-Marseille University in France; and Erin Hecht and Nada Khreisheh of Emory University.

Stone tools - shaped by striking a stone "core" with a piece of bone, antler, or another stone - provide some of the most abundant evidence of human behavioral change over time. Simple Oldowan stone flakes are the earliest known tools, dating back 2.6 million years. The Late Acheulean hand axe goes back 500,000 years. While it's relatively easy to learn to make an Oldowan flake, the Acheulean hand axe is harder to master, due to its lens-shaped core tapering down to symmetrical edges.

"We wanted to tease apart and compare what parts of the brain were most actively involved in these stone tool technologies, particularly the role of motor control versus strategic thinking," Stout says.

The researchers recruited six subjects, all archeology students at Exeter University, to train in making stone tools, a skill known as "knapping." The subjects' skills were evaluated before and after they trained and practiced. For Oldowan evaluations, subjects detached five flakes from a flint core. For Acheulean evaluations, they produced a tool from a standardized porcelain core.

At the beginning, middle and end of the 18-month experiment, subjects underwent functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) scans of their brains while they watched videos. The videos showed rotating stone cores marked with colored cues: A red dot indicated an intended point of impact, and a white area showed the flake predicted to result from the impact. The subjects were asked the following questions:

"If the core were struck in the place indicated, is what you see a correct prediction of the flake that would result?"

"Is the indicated place to hit the core a correct one given the objective of the technology?"

The subjects responded by pushing a "yes" or "no" button.

Answering the first question, how a rock will break if you hit it in a certain place, relies more on reflexive, perceptual and motor-control processes, associated with posterior portions of the brain. Stout compares it to the modern-day rote reflex of a practiced golf swing or driving a car.

The second question - is it a good idea to hit the core in a certain spot if you want to make a hand axe - involves strategic thinking, such as planning the route for a road trip. "You have to think about information that you have stored in your brain, bring it online, and then make a decision about each step of the trip," Stout says.

This so-called executive control function of the brain, associated with activity in the prefrontal cortex, allows you to project what's going to happen in the future and use that projection to guide your action. "It's kind of like mental time travel, or using a computer simulation," Stout explains. "It's considered a high level, human cognitive capacity."

The researchers mapped the skill level of the subjects onto the data from their brain scans and their responses to the questions.

Greater skill at making tools correlated with greater accuracy on the video quiz for predicting the correct strategy for making a hand axe, which was itself correlated with greater activity in the prefrontal cortex. "These data suggest that making an Acheulean hand axe is not simply a rote, auto pilot activity of the brain," Stout says. "It requires you to engage in some complicated thinking."

Most of the hand axes produced by the modern hands and minds of the study subjects would not have cut it in the Stone Age. "They weren't up to the high standards of 500,000 years ago," Stout says.

A previous study by the researchers showed that learning to make stone tools creates structural changes in fiber tracts of the brain connecting the parietal and frontal lobes, and that these brain changes correlated with increases in performance. "Something is happening to strengthen this connection," Stout says. "This adds to evidence of the importance of these brain systems for stone tool making, and also shows how tool making may have shaped the brain evolutionarily."

Stout recently launched a major, three-year archeology experiment that will build on these studies and others. Known as the Language of Technology project, the experiment involves 20 subjects who will each devote 100 hours to learning the art of making a Stone Age hand axe, and also undergo a series of MRI scans. The project aims to hone in whether the brain systems involved in putting together a sequence of words to make a meaningful sentence in spoken language overlap with systems involved in putting together a series of physical actions to reach a meaningful goal.


Neanderthals manipulated the bodies of adults and children shortly after death


Neanderthals from the French region of Poitou-Charentes cut, beat and fractured the bones of their recently deceased companions, as revealed by the fossil remains of two adults and a child found at the Marillac site. These manipulations have been observed at other Neanderthal sites, but scientists still do not know whether they did this for food or ceremony.

Since the Marillac site in France was unearthed, the discovery of fossil remains of animals (90% belonging to reindeer), humans and Mousterian tools has enabled the site to be identified as a hunting area for Neanderthals (Homo neanderthalensis). But the most surprising thing about the site is the presence of a large quantity of bone remains of these hominids, many of which are yet to be analysed.

Now, a study published in the American Journal of Physical Anthropology has for the first time analysed the fragments of three individuals found between 1967 and 1980 at the French site dating back some 57,600 years. These are an incomplete diaphysis (middle part of long bones) of a right radius, another of a left fibula and the majority of a right femur. The latter belonged to a child.

When compared to the remains of other Neanderthals and modern humans, the scientists confirm not only the strength and rounded form of Neanderthal bones, but they also identify on the three bones manipulations made very shortly after the individuals' death.

As María Dolores Garralda, professor at the Complutense University of Madrid, a researcher at the University of Bordeaux in France and the main author of the study, explains to SINC: "Some Neanderthal groups cut and tore apart child or adult corpses shortly after death (perimortem) using lytic instruments."

Cuts, beating, fracturing and stains

The femur fragment, which appears to be from a child who died at the age of 9 or 10, shows two large cut marks half a centimetre apart. From its state of preservation, the researchers suggest that the bone was fractured when still fresh with the aim of separating the upper and lower extreme of the femur, where the joints are located.

"The upper edge exhibits marks of a "post-mortem" impact with conchoidal markings (those that does not follow natural separation positions)," the study sets out. The lower region possesses a clear, oblique spiral break which seems to have occurred while the bone was fresh.

"Given the morphology of the fractures, it may be that the body of this child was manipulated shortly after death. The right leg received a series of blows that fractured the femur, and the cut marks identified are anthropic in nature; in other words, there is no visible evidence of animal bites," Garralda notes.

The bones of the two adults show these and other markings. The fragment of the radius, possibly belonging to a man, also has small, fine cut marks made with flint tools shortly after death. "The most significant are three striations together crossing over each other while the bone was still fresh," the study describes.

As for the fibula, although the fresh fractures of both extremes can be seen, there are also signs of percussion at the lower end. But "there is no evidence of cuts or traces of carnivores' teeth," the researcher insists. Unlike to the other two fragments of bones analysed, the fibula fossil exhibits numerous manganese stains; manganese is a very abundant mineral in the cave which gives bones a black colour.

Cannibalism or rituals?

The team of scientists does not know why they did this: "They might have been rituals - still in the 21st century these continue in certain parts of the world - or for food - gastronomic cannibalism or due to need," asserts the expert, who remains cautious regarding the hypothesis of cannibalism, due to the large number of animal bones found on the site which could have been Neanderthals' food.

"To date we have been able to demonstrate these manipulations at several Neanderthal sites in Europe, which are of course much more recent, including in groups of contemporary humans, but we have not been able to demonstrate the consumption of human meat by Neanderthals (although this has indeed been done in other much more modern populations)," Garralda details.

In addition to these perimortem corporal manipulations carried out by members of the group, other bones found at the Marillac site, also fragmented, exhibit signs of gnawing or digestion by animals. "These markings and deformations are clearly distinguishable from those studied in the three Neanderthal diaphysis," the expert concludes.

Wednesday, April 8, 2015

Neolithic Northern Europeans Foragers, Not Farmers

Northern Europeans in the Neolithic period initially rejected the practice of farming, which was otherwise spreading throughout the continent, a team of researchers has found. Their findings offer a new wrinkle in the history of a major economic revolution that moved civilizations away from foraging and hunting as a means for survival.

"This discovery goes beyond farming," explains Solange Rigaud, the study's lead author and a researcher at the Center for International Research in the Humanities and Social Sciences (CIRHUS) in New York City. "It also reveals two different cultural trajectories that took place in Europe thousands of years ago, with southern and central regions advancing in many ways and northern regions maintaining their traditions."

CIRHUS is a collaborative arrangement between France's National Center for Scientific Research (CNRS) and New York University.

The study, whose other authors include Francesco d'Errico, a professor at CNRS and Norway's University of Bergen, and Marian Vanhaeren, a professor at CNRS, appears in the journal PLOS ONE.

In order to study these developments, the researchers focused on the adoption or rejection of ornaments--certain types of beads or bracelets worn by different populations. This approach is suitable for understanding the spread of specific practices--previous scholarship has shown a link between the embrace of survival methods and the adoption of particular ornaments. However, the PLOS ONE study marks the first time researchers have used ornaments to trace the adoption of farming in this part of the world during the Early Neolithic period (8,000-5,000 BCE).

It has been long established that the first farmers came to Europe 8,000 years ago, beginning in Greece and marking the start of a major economic revolution on the continent: the move from foraging to farming over the next 3,000 years. However, the pathways of the spread of farming during this period are less clear.

To explore this process, the researchers examined more than 200 bead-types found at more than 400 European sites over a 3,000-year period. Previous research has linked farming and foraging populations with the creation and adornment of discrete types of beads, bracelets, and pendants. In the PLOS ONE study, the researchers traced the adoption of ornaments linked to farming populations in order to elucidate the patterns of transition from foraging and hunting to farming.

Their results show the spread of ornaments linked to farmers--human-shaped beads and bracelets composed of perforated shells--stretching from eastern Greece and the Black Sea shore to France's Brittany region and from the Mediterranean Sea northward to Spain. By contrast, the researchers did not find these types of ornaments in the Baltic region of northern Europe. Rather, this area held on to decorative wear typically used by hunting and foraging populations--perforated shells rather than beads or bracelets found in farming communities.

"It's clear hunters and foragers in the Baltic area resisted the adoption of ornaments worn by farmers during this period," explains Rigaud. "We've therefore concluded that this cultural boundary reflected a block in the advancement of farming--at least during the Neolithic period."

Monday, April 6, 2015

3,000-year-old Egyptian artifacts in a cave near Kibbutz Lahav in southern Israel


A ring unearthed during the excavation is inlaid with a seal showing an Egyptian warrior holding a shield and sword.
Credit: Unit for the Prevention of Antiquities Robbery of the Israel Antiquities Authority


 

"During this period, Canaan was ruled by Egypt," Daphna Ben-Tor, curator of Egyptian archaeology at the Israel Museum, explained in a statement from the IAA.

"The names of kings appeared on some of the seals," Ben-Tor added. "Among other things, we can identify a sphinx lying opposite the name of the pharaoh Thutmose, who reigned from about 1504-1450 B.C. Another scarab seal bears the name of Amenhotep, who reigned from about 1386-1349 B.C. Still another scarab depicts Ptah, the principal god of the city of Memphis."

 

The collection of artifacts found in the cave includes faience amulets depicting Egyptian gods and scarab seals depicting Egyptian pharaohs.
Credit: Clara Amit, courtesy of the Israel Antiquities Authority

 

Thursday, April 2, 2015

A genetic map of the British Isles



Many people in the UK feel a strong sense of regional identity, and it now appears that there may be a scientific basis to this feeling, according to a landmark new study into the genetic makeup of the British Isles.

An international team, led by researchers from the University of Oxford, UCL (University College London) and the Murdoch Childrens Research Institute in Australia, used DNA samples collected from more than 2,000 people to create the first fine-scale genetic map of any country in the world.

Their findings, published in Nature, show that prior to the mass migrations of the 20th century there was a striking pattern of rich but subtle genetic variation across the UK, with distinct groups of genetically similar individuals clustered together geographically.

By comparing this information with DNA samples from over 6,000 Europeans, the team was also able to identify clear traces of the population movements into the UK over the past 10,000 years. Their work confirmed, and in many cases shed further light on, known historical migration patterns.

Key findings

- There was not a single "Celtic" genetic group. In fact the Celtic parts of the UK (Scotland, Northern Ireland, Wales and Cornwall) are among the most different from each other genetically. For example, the Cornish are much more similar genetically to other English groups than they are to the Welsh or the Scots.

- There are separate genetic groups in Cornwall and Devon, with a division almost exactly along the modern county boundary.

- The majority of eastern, central and southern England is made up of a single, relatively homogeneous, genetic group with a significant DNA contribution from Anglo-Saxon migrations (10-40% of total ancestry). This settles a historical controversy in showing that the Anglo-Saxons intermarried with, rather than replaced, the existing populations.

- The population in Orkney emerged as the most genetically distinct, with 25% of DNA coming from Norwegian ancestors. This shows clearly that the Norse Viking invasion (9th century) did not simply replace the indigenous Orkney population.

- The Welsh appear more similar to the earliest settlers of Britain after the last ice age than do other people in the UK.

- There is no obvious genetic signature of the Danish Vikings, who controlled large parts of England ("The Danelaw") from the 9th century.

- There is genetic evidence of the effect of the Landsker line - the boundary between English-speaking people in south-west Pembrokeshire (sometimes known as "Little England beyond Wales") and the Welsh speakers in the rest of Wales, which persisted for almost a millennium.

- The analyses suggest there was a substantial migration across the channel after the original post-ice-age settlers, but before Roman times. DNA from these migrants spread across England, Scotland, and Northern Ireland, but had little impact in Wales.

- Many of the genetic clusters show similar locations to the tribal groupings and kingdoms around end of the 6th century, after the settlement of the Anglo-Saxons, suggesting these tribes and kingdoms may have maintained a regional identity for many centuries.

The Wellcome Trust-funded People of the British Isles study analysed the DNA of 2,039 people from rural areas of the UK, whose four grandparents were all born within 80km of each other. Because a quarter of our genome comes from each of our grandparents, the researchers were effectively sampling DNA from these ancestors, allowing a snapshot of UK genetics in the late 19th Century. They also analysed data from 6,209 individuals from 10 (modern) European countries.

To uncover the extremely subtle genetic differences among these individuals the researchers used cutting-edge statistical techniques, developed by four of the team members. They applied these methods, called fineSTRUCTURE and GLOBETROTTER, to analyse DNA differences at over 500,000 positions within the genome. They then separated the samples into genetically similar individuals, without knowing where in the UK the samples came from. By plotting each person onto a map of the British Isles, using the centre point of their grandparents' birth places, they were able to see how this distribution correlated with their genetic groupings.

The researchers were then able to "zoom in" to examine the genetic patterns in the UK at levels of increasing resolution. At the broadest scale, the population in Orkney (islands to the north of Scotland) emerged as the most genetically distinct. At the next level, Wales forms a distinct genetic group, followed by a further division between north and south Wales. Then the north of England, Scotland, and Northern Ireland collectively separate from southern England, before Cornwall forms a separate cluster. Scotland and Northern Ireland then separate from northern England. The study eventually focused at the level where the UK was divided into 17 genetically distinct clusters of people.

Dr Michael Dunn, Head of Genetics & Molecular Sciences at the Wellcome Trust, said: "These researchers have been able to use modern genetic techniques to provide answers to the centuries' old question - where we come from. Beyond the fascinating insights into our history, this information could prove very useful from a health perspective, as building a picture of population genetics at this scale may in future help us to design better genetic studies to investigate disease."

Quotes from the paper authors:

Sir Walter Bodmer from the University of Oxford, who conceived the People of the British Isles study and co-led the work, said: "The People of the British Isles study gave us a wonderful opportunity to learn about the fine-scale genetic patterns in the UK population. A key part of our success was collecting DNA from a geographically diverse group of people who are representative of their location. We are very grateful to all the volunteers who participated in the study."

Professor Peter Donnelly, Director of the Wellcome Trust Centre for Human Genetics at the University of Oxford, who co-led the research, said: "It has long been known that human populations differ genetically, but never before have we been able to observe such exquisite and fascinating detail. By coupling this with our assessment of the genetic contributions from different parts of Europe we were able to add to our understanding of UK population history."

Dr Stephen Leslie, of Murdoch Childrens Research Institute in Australia, and one of the lead authors of the study, said: "Rich genetic information such as this tells us a great deal about our history and augments what we know already from archaeology, linguistic and historical records. Much of what we've learned about our history comes from the successful people of society, as they leave the strongest marks on history and archaeology. By using genetics and powerful statistical methods, we have been able to tell the story of the masses."

Dr Garrett Hellenthal, co-lead author of the study at UCL (University College London), said: "To tease out the subtle genetic differences between UK regions we had to use sophisticated statistical methods that model how our genomes are made up of stretches of DNA, passed down the generations from our ancestors".

Professor Simon Myers, from the University of Oxford, who co-led the development of the statistical approaches used in the study, said: "In future, increasingly large datasets will allow us to learn even more about the genetic history of the UK, and the similarly rich histories of other world regions, by applying similar techniques."




Paleolithic stone tools found among elephant remains some 500,000 years old at site in Revadim, Israe



Some 2.5 million years ago, early humans survived on a paltry diet of plants. As the human brain expanded, however, it required more substantial nourishment — namely fat and meat — to sustain it. This drove prehistoric man, who lacked the requisite claws and sharp teeth of carnivores, to develop the skills and tools necessary to hunt animals and butcher fat and meat from large carcasses.

Among elephant remains some 500,000 years old at a Lower Paleolithic site in Revadim, Israel, Prof. Ran Barkai and his graduate students Natasha Solodenko and Andrea Zupanchich of Tel Aviv University's Department of Archaeology and Ancient Near Eastern Cultures recently analyzed "handaxes" and "scrapers," universally shaped and sized prehistoric stone tools, replete with animal residue.

The research, published recently in PLOS One, represents the first scientifically verified direct evidence for the precise use of Paleolithic stone tools: to process animal carcasses and hides. The research was done in collaboration with Drs. Stella Ninziante Cesaro and Cristina Lemorini of La Sapienza, University of Rome, and Dr. Ofer Marder of Ben-Gurion University of the Negev.

Putting the puzzle together
"There are three parts to this puzzle: the expansion of the human brain, the shift to meat consumption, and the ability to develop sophisticated technology to meet the new biological demands. The invention of stone technology was a major breakthrough in human evolution," Prof. Barkai said. "Fracturing rocks in order to butcher and cut animal meat represents a key biological and cultural milestone.

"At the Revadim quarry, a wonderfully preserved site a half-million years old, we found butchered animal remains, including an elephant rib bone which had been neatly cut by a stone tool, alongside flint handaxes and scrapers still retaining animal fat. It became clear from further analyses that butchering and carcass processing indeed took place at this site."

Through use-wear analysis — examining the surfaces and edges of the tools to determine their function — and the Fourier Transform InfraRed (FTIR) residue analysis which harnesses infrared to identify signatures of prehistoric organic compounds, the researchers were able to demonstrate for the first time direct proof of animal exploitation by flint tools.

"Archaeologists have until now only been able to suggest scenarios about the use and function of such tools. We don’t have a time machine," Prof. Barkai said. "It makes sense that these tools would be used to break down carcasses, but until evidence was uncovered to prove this, it remained just a theory."

While the question of their function and production remained unanswered until now, there was little doubt that the handaxe and scraper, found at prehistoric sites all around the world, were distinct, used for specific purposes. By replicating the flint tools for a modern butchering experiment, and then comparing the replicas with their prehistoric counterparts, the researchers determined that the handaxe was prehistoric man's sturdy "Swiss army knife," capable of cutting and breaking down bone, tough sinew, and hide. The slimmer, more delicate scraper was used to separate fur and animal fat from muscle tissue.

"Prehistoric peoples made use of all parts of the animal," said Prof. Barkai. "In the case of the massive elephant, for example, they would have needed to use both tools to manage such a challenging task. The knowledge of how to make these tools was precious, and must have been passed along from generation to generation, because these tools were reproduced the same way across great territorial expanses and over hundreds of thousands of years.

"In this thousand-piece puzzle called archaeology, sometimes we find pieces that connect other pieces together. This is what we have found with the stone tools and animal bones."

Beer vessels provide evidence of an ancient Egyptian population in the area of in downtown Tel Aviv, 5,000 years ago.

Fragments of ancient pottery vessels used to prepare beer, unearthed during recent salvage excavations in downtown Tel Aviv, provide evidence indicating the presence of an ancient Egyptian population from more than 5,000 years ago.

“We found 17 pits in the excavations, which were used to store agricultural produce in the Early Bronze Age [3500-3000-BCE],” said Diego Barkan, director of the authority’s excavation.

“Among the hundreds of pottery sherds that characterize the local culture, a number of fragments of large ceramic basins were discovered that were made in an Egyptian tradition, and were used to prepare beer.”

“The vessels were manufactured with straw temper, or some other organic material in order to strengthen them, a method not customary in the local pottery industry,” he continued.

Barkan added that similar vessels were found in an Egyptian administrative building that was excavated in southern Israel’s Ein Habesor moshav.

“On the basis of previously conducted excavations in the region, we knew there is an Early Bronze Age site here, but this excavation is the first evidence we have of an Egyptian occupation in the center of Tel Aviv at that time,” he said.

Barkan said that the remnants represent the northernmost evidence ever obtained of an Egyptian presence in the Early Bronze Age.

“Until now, we were only aware of an Egyptian presence in the northern Negev and southern coastal plain, whereby the northernmost point of Egyptian occupation occurred in Azor,” he explained. “Now we know that they also appreciated what the Tel Aviv region had to offer, and that they too knew how to enjoy a glass of beer, just as Tel Avivians do today.”

According to the archeologist, beer was the “national drink of Egypt” in ancient times, and was bought and sold like other basic commodities, such as bread.

“Beer was consumed by the entire population, regardless of age, gender or status,” he said.

“It was made from a mixture of barley and water that was partially baked and then left to ferment in the sun.”