DNA data offers scientific look at 500 years of extramarital sex in Western Europe

By: Thomas Schmitt Attorney on November 14, 2019 / comment : 0 Anthropology, Genetics, Society, Western Europe

These days it's easy to resolve questions about paternity with over-the-counter test kits. Now, researchers have put DNA evidence together with long-term genealogical data to explore similar questions of biological fatherhood on a broad scale among people living in parts of Western Europe over the last 500 years.

Credit: Getty Images

The findings reported in Current Biology yielded some surprises. While the number of so-called extra-pair paternity (EPP) events overall was (not surprisingly) fairly low, their frequency varied considerably among people depending on their circumstances. Specifically, evidence of EPP events turned up much more often in people of lower socioeconomic status who lived in densely populated cities in the 19th century.

"Of course, extra-pair paternity, especially due to adultery, is a popular topic in gossip, jokes, TV series, and literature," said Maarten Larmuseau of KU Leuven and Histories, Belgium. "But scientific knowledge on this phenomenon is still highly limited, especially regarding the past.

"Our research shows that the chance of having extra-pair paternity events in your family history really depends on the social circumstances of your ancestors. If they lived in cities and were of the lower socioeconomic classes, the chances that there were EPP events in your family history are much higher than if they were farmers."

Evolutionarily speaking, it's clear that remaining faithful to one's partner isn't always the most advantageous strategy. Males may benefit from straying by siring extra offspring; females may benefit by mating with superior males. But in human societies over time, how often has EPP really happened?

In the new study, Larmuseau's team took the first broad look at this question to find that social context really matters. Their study covered a time period of several centuries during which there were dramatic changes in the human social environment, including the rapid urbanization that accompanied the Industrial Revolution in 19th century Western Europe. To estimate historical EPP rates among married couples, they identified 513 pairs of contemporary adult males living in Belgium and the Netherlands who, based on genealogical evidence, shared a common paternal ancestor and therefore--barring an EPP event--should have carried the same Y chromosome.

The evidence showed no significant difference in EPP rates between countries despite key religious differences, they report. But they varied widely with socioeconomic status and population density. The EPP rate was much lower among farmers and more well-to-do craftsmen and merchants (about 1%) than among lower class laborers and weavers (about 4%).

EPP rates also rose with population density. Putting the two together, the researchers report that the estimated EPP rates for the families varied by more than one order of magnitude, from about 0.5% among the middle to high classes and farmers living in the most sparsely populated towns to almost 6% for the low socioeconomic classes living in the most densely populated cities.

The researchers say the findings support evolutionary theories suggesting that individual incentives and opportunities for seeking or preventing extra-pair mating should depend on the social context. They also debunk the notion that EPP rates in Western society are generally high, they say, noting that the evidence puts average rates at around 1%.

Larmuseau says an interdisciplinary perspective will be important to understanding why certain factors like population density and socio-economic status have had such a strong influence on the EPP rate. "This is highly relevant because the causes of historical EPP events are hidden and diverse," he said.

Source: Cell Press [November 14, 2019]

Complex society discovered in birds

By: Thomas Schmitt Attorney on November 04, 2019 / comment : 0 Biology, Evolution, Society, Wildlife

Multilevel societies have, until now, only been known to exist among large-brained mammals including humans, other primates, elephants, giraffes, and dolphins. Now, scientists from the Max Planck Institute of Animal Behavior and the University of Konstanz report the existence of a multilevel society in a small-brained bird, the vulturine guineafowl (Acryllium vulturinum). The study, published in Current Biology, suggests that the birds can keep track of social associations with hundreds of other individuals--challenging the notion that large brains are a requirement for complex societies and providing a clue as to how these societies evolved.

Vulturine guineafowl move in highly cohesive groups. This cohesion allows them to coordinate their actions as they move together through the landscape, and therefore maintain stable group membership  over extensive periods of time [Credit: James Klarevas]

Multilevel societies occur when social units, such as pairs, of animals form groups that have stable membership, and these groups then associate preferentially with specific other groups. Because this requires the animals to keep track of individuals in both their own and other groups, the assumption has long been that multilevel societies should only exist in species with the intelligence to cope with this complexity. While many bird species live in groups, these are either open, lacking long-term stability, or highly territorial, lacking associations with other groups.

Vulturine guineafowl, however, present a striking exception: the researchers observed these birds, that are from an ancient lineage resembling dinosaurs more than birds, behaving highly cohesively without exhibiting the signature intergroup aggression that is common in other group-living birds. And they can manage this despite having a relatively small brain, even relative to other birds. "They seemed to have the right elements to form complex social structures, and yet nothing was known about them," says Danai Papageorgiou, lead author on the paper and a PhD student at the Max Planck Institute of Animal Behavior.

The study, which is the first ever conducted on the species, involved tracking social relationships over the course of multiple seasons in a population of over 400 adult birds in a field site in Kenya. The researchers individually marked all birds in the population, and by observing them they discovered that the population comprised 18 distinct social groups (with 13 to 65 individuals in each). What struck the researchers is that these groups remained stable, despite regularly overlapping with one or more other groups both during the day and at night-time roosts.

Groups of vulturine guineafowl can become very large, and when multiple groups come into contact the number of birds moving together can reach into the hundreds. However, when these 'super-groups' eventually split, they do so back  into their original stable group units, meaning that individuals are knowledgeable about who is part  of their group and who is not [Credit: Danai Papageorgiou]

To see if these groups preferentially associated with one another, the researchers attached GPS tags to a sample of individuals in each group. This meant that the position of every single group was recorded continuously each day, which allowed researchers to simultaneously observe how all 18 groups in the population were interacting. The researchers found that groups associated with each other based on preference, rather than random encounters, and also showed that intergroup associations were more likely to take place during specific seasons and around particular physical features in the landscape.

"To our knowledge, this is the first time a social structure like this has been described for birds," says Papageorgiou. "It is remarkable to observe hundreds of birds coming out of a roost and splitting up perfectly into completely stable groups every single day. How do they do that? It's obviously not just about being smart."

Despite being understudied, guineafowl have challenged our understanding of how sociality has evolved. "This discovery raises a lot of questions about the mechanisms underlying complex societies and has opened up exciting possibilities of exploring what is it about this bird that has made them evolve a social system that is in many ways more comparable to a primate than to other birds," says Damien Farine, senior author on the paper and a Principal Investigator at the Max Planck Institute of Animal Behavior and the Centre for the Advanced Study of Collective Behaviour at the University of Konstanz.

But, vulturine guineafowl hold some important clues about how complex societies might have evolved. "Many examples of multilevel societies -- primates, elephants and giraffes -- might have evolved under similar ecological conditions as vulturine guineafowl," says Farine.

Source: Max Planck Society [November 04, 2019]

Private property, not productivity, precipitated Neolithic agricultural revolution

By: Thomas Schmitt Attorney on October 11, 2019 / comment : 0 Archaeology, Iran, Iraq, Middle East, Society

Humankind first started farming in Mesopotamia about 11,500 years ago. Subsequently, the practices of cultivating crops and raising livestock emerged independently at perhaps a dozen other places around the world, in what archaeologists call the Neolithic Agricultural Revolution. It's one of the most thoroughly-studied episodes in prehistory - but a new paper in the Journal of Political Economy shows that most explanations for it don't agree with the evidence, and offers a new interpretation.

Cave painting of cow & horses, Lascaux, France [Credit: Alamy]

With farming came a vast expansion of the realm over which private property governed access to valued goods, replacing the forager social norms around sharing food upon acquisition. A common explanation is that farming increased labor productivity, which then encouraged the adoption of private property by providing incentives for the long-term investments required in a farming economy.

"But it's not what the data are telling us", says Santa Fe Institute economist Samuel Bowles, a co-author of the paper. "It is very unlikely that the number of calories acquired from a day's work at the advent of farming made it a better option than hunting and gathering and it could well have been quite a bit worse."

Prior studies, including those of human and animal bones, suggest that farming actually took an extreme nutritional toll on early adopters and their livestock. So why farm in the first place?

Some have suggested an inferior technology could have been imposed by political elites as a strategy for extracting taxes, tribute, or rents. But farming was independently adopted millennia before the emergence of governments or political elites capable of imposing a new way of life on heavily-armed foraging communities.

Bowles and co-author Jung-Kyoo Choi, an economist at Kyungpook National University in South Korea, use both evolutionary game theory and archaeological evidence to propose a new interpretation of the Neolithic. Based on their model, a system of mutually recognized private property rights was both a precondition for farming and also a means of limiting costly conflicts among members of a population.

While rare among foragers, private property did exist among a few groups of sedentary hunter-gatherers. Among them, farming could have benefited the first adopters because it would have been easier to establish the private possession of cultivated crops and domesticated animals than for the diffuse wild resources on which hunter-gatherers relied.

"It is a lot easier to define and defend property rights in a domesticated cow than in a wild kudu," says Choi. "Farming initially succeeded because it facilitated a broader application of private property rights, not because it lightened the toil of making a living."

Source: Santa Fe Institute [October 11, 2019]

Social inequality in Bronze Age households

By: Thomas Schmitt Attorney on October 09, 2019 / comment : 0 Archaeology, Europe, Germany, Society, Western Europe

Archaeogenetic analyses provide new insights into social inequality 4000 years ago: nuclear families lived together with foreign women and individuals from lower social classes in the same household.

Illustration of Bronze Age Europeans [Credit: bunterhund]

Social inequality already existed in southern Germany 4000 years ago, even within one household, a new study published in the Science finds. Archaeological and archaeogenetic analyses of Bronze Age cemeteries in the Lech Valley, near Augsburg, show that families of biologically related persons with higher status lived together with unrelated women who came from afar and also had a high status, according to their grave goods.

In addition, a larger number of local but clearly less well-off individuals were found in the same cemeteries, which were small gravesites associated with single homesteads. The researchers conclude that social inequality was already part of households structures in that time and region. Whether the less well-off individuals were servants or slaves can only be speculated upon.

In Central Europe, the Bronze Age covers the period from 2200 to 800 BCE. At that time people acquired the ability to cast bronze. This knowledge led to an early globalization, since the raw materials had to be transported across Europe. In an earlier study, the current team had shown that, 4000 years ago, the majority of women in the Lech Valley came from abroad and may have played a decisive role in the transfer of knowledge. Supraregional networks were apparently fostered by marriages and institutionalized forms of mobility.

The current archaeological-scientific project was situated at the Heidelberg Academy of Sciences and led by Philipp Stockhammer from the Ludwig-Maximilians-Universitaet (LMU) in Munich together with Johannes Krause and Alissa Mittnik from the Max Planck Institute for the Science of Human History in Jena and the University of Tubingen. The researchers attempted to investigate the effects of this mobility and other concurrent changes.

The excavations south of Augsburg, which took place at the sites of Bronze Age homestead farms and their associated graveyards, enabled archaeologists to zoom into the Bronze Age in unprecedented resolution in order to investigate how the transition from the Stone Age to the Bronze Age affected the households of that time.

"Wealth was correlated with either biological kinship or foreign origin. The nuclear family passed on their property and status over generations. But at every farm we also found poorly equipped people of local origin," says Philipp Stockhammer, Professor of Prehistoric Archaeology at LMU Munich. This finding suggests a complex social structure of households, as is also known from Classical Greece and Rome.

In Roman times, slaves were also part of the family unit, but had a different social status. However, these people in the Lech Valley lived over 1500 years earlier. "This shows how long the history of social inequality in family structures goes back in time," Stockhammer continues.

Stable social structures over 700 years

It was already known that the first larger hierarchical social structures evolved in the Bronze Age. The findings of the current study were surprising in that social differences existed within a single household and were maintained over generations.

Grave goods can reveal the social status of the deceased to archaeologists. In the Lech Valley, weapons and elaborate jewelry were only found in the graves of closely related family members and women who came into the family from long distances, up to several hundred kilometers away. Other unrelated individuals of local origin were found in the same cemeteries without such high-status grave goods.

This study also succeeded in reconstructing for the first time family trees from prehistoric cemeteries spanning four to five generations. Surprisingly, however, these only included the male lineages. The female descendants apparently left the farms where they reached adulthood. The mothers of the sons, on the other hand, were all women who had moved in from afar.

"Archaeogenetics provides us with a completely new view of the past. Until recently, we would not have thought it possible to examine marriage rules, social structure and social inequality in prehistory," says Johannes Krause, Director of the Department of Archaeogenetics at the Max Planck Institute for Human History.

The archaeologists on the project were able to compare the degree of kinship with the grave goods and the location of the graves and show how couples and their children were buried. This was made possible by generating genome-wide data from more than 100 ancient skeletons, which allowed reconstructing family tress from prehistoric bone. Only the genetically unrelated local members of a household were buried without significant grave goods.

"Unfortunately, we cannot say whether these individuals were servants and maids or perhaps even enslaved," says Alissa Mittnik. "What is certain is that through the male lines, the farmsteads were passed from generation to generation and this system was stable over at least 700 years, across the transition from the Stone Age to the Bronze Age. The Lech Valley shows how early social inequality within individual households can be found."

Source: Ludwig-Maximilians-Universitat Munchen [October 09, 2019]

Inequality: What we've learned from the 'Robots of the late Neolithic'

By: Thomas Schmitt Attorney on September 18, 2019 / comment : 0 Archaeology, Eurasia, Europe, Middle East, Society

Seven thousand years ago, societies across Eurasia began to show signs of lasting divisions between haves and have-nots. In new research published in the journal Antiquity, scientists chart the precipitous surge of prehistoric inequality and trace its economic origins back to the adoption of ox-drawn ploughs.

A Canadienne ox at a historic village in New Brunswick, Canada [Credit: Amy Bogaard]

Their findings challenge a long-held view that inequality arose when human societies first transitioned from hunting and gathering to agriculture. According to the researchers, it was not agriculture per se that ushered in substantial wealth inequalities, but instead a transformation of farming that made land more valuable and labour less so.

"Ox drawn ploughs were the robots of the late Neolithic," explains co-author Samuel Bowles, an economist at the Santa Fe Institute. The oxen were a form of labour-saving technology that led to a decoupling of wealth from labour - a decoupling fundamental to modern wealth inequality. "The effect was the same as today: growing economic disparities between those who owned the robots and those whose work the robots displaced."

In the first of two companion papers, the researchers present new statistical methods for comparing wealth inequality across different kinds of wealth, different societies, in different regions, at different times in history. Their analysis of data from 150 archaeological sites reveals a steep increase in inequality in Eurasia from around 4,000 BC -- several millennia after the advent of agriculture.

"The surprise here isn't so much that inequality takes off later on, it's that it stayed low for such a long time," says lead author Amy Bogaard, an archaeologist based at the University of Oxford who is also an external professor at the Santa Fe Institute.

"The usual story -- that the societies that adopted agriculture became more unequal -- is no longer valid because we observed that some societies who adopted agriculture were remarkably egalitarian for thousands of years," says co-author Mattia Fochesato, an economist at Bocconi University.

Before around 4,000 BC, societies across the Middle East and Europe cultivated a patchwork of small garden plots, which Bogaard likens to present-day "allotments" in the UK. Families would have grown a variety cereal grains, as well as lentils, peas, and other pulse crops that needed to be harvested by hand. Notably, they would have tilled the soil by hand using hoes, in some cases also with the help of unspecialized cattle (such as aging milk cows) to pull ploughs, and carefully monitored their gardens during the growing season to protect them from wild animals. "It was quite a busy landscape, with lots of people working in and around these garden plots."

Humble ox or Neolithic robot? [Credit: Amy Bogaard]

Then something changed. Farmers who were well resourced enough to raise and maintain specialized plough oxen saw new opportunities in farming additional land. A single farmer with an ox team could cultivate ten times or more land than a hoe farmer, and would begin to acquire more and more land to cultivate. Those who owned land and ox teams also began to opt for more stress-tolerant crops, like barley or certain kinds of wheat, that didn't require much labour.

By the second millennium BC in many farming landscapes fields stretched to the horizon, and societies were deeply divided between wealthy landowners, who passed their holdings on to their children, and land-poor or landless families.

The mechanism that drove this change is detailed in an economic model in the researchers' second paper. It reveals a key distinction between farming systems where human labour was the limiting factor for production, versus systems where human labour was more expendable, and where land was the limiting factor.

"So long as labour was the key input for production, inequality was limited because families did not differ much in how much labor they could deploy to produce crops, " Fochesato explains. "But when the most important input became land, differences between families widened because land and other material forms of wealth could be accumulated and transmitted over generations. By chance, or force, or hard work, some families came to have a lot more than others. Then radical inequality arose."

The two new papers are part of a growing body of scientific research that is applying comparative economic measures to the archaeological record. Much of the work is part of Bowles' long-running series of interdisciplinary workshops on the origins of wealth inequality, which convene annually at the Santa Fe Institute. The new research supports previous findings by archaeologist Tim Kohler et al (Nature, 2017), which drew attention to a markedly greater wealth inequality in post-Neolithic Eurasia than in the Americas, where domesticated draft animals would not have been available.

One consequence of inequality, Bogaard notes, is that the most unequal societies tended to be more fragile and susceptible to political upheaval or climate change.

The takeaway for people today is that "if there are opportunities to monopolize land or other key assets in a production system, people will. And if there aren't institutional or other redistributive mechanisms, inequality is always where we're going to end up." Land is still a relevant asset, Bogaard says, "but there are many other kinds of assets now that we should think about people's capacity to own and benefit from."

Author: Jenna Marshall | Source: Santa Fe Institute [September 18, 2019]

Community size matters when people create a new language

By: Thomas Schmitt Attorney on July 17, 2019 / comment : 0 Anthropology, Human Evolution, Linguistics, Society

Why are languages so different from each other? After comparing more than two thousand languages, scientists noticed that languages with more speakers are usually simpler than smaller languages. For instance, most English nouns can be turned into plurals by simply adding -s, whereas the German system is notoriously irregular. Linguists have proposed that languages adapt to fit different social structures.

Credit: iStockphoto, Kronick

"But we actually don't know whether it is the size of the community that drives the difference in complexity," says lead author Limor Raviv from the Max Planck Institute for Psycholinguistics. Perhaps the bigger languages have simpler grammars because they cover larger geographical space and speakers are far from each other, or because large communities have more contact with outsiders. Together with her colleagues, Antje Meyer from the Max Planck Institute for Psycholinguistics and Radboud University and Shiri Lev-Ari from the Royal Holloway University of London, Raviv set out to test whether community size alone plays a role in shaping grammar.

'Wowo-ik' and 'wowo-ii'

To test the role of group size experimentally, the psycholinguists used a communication game. In this game, participants had to communicate without using any language they know, leading them to create a new language. The goal of the game was to communicate successfully about different novel scenes, using only invented nonsense words.

A 'speaker' would see one of four shapes moving in some direction on a screen and type in nonsense words to describe the scene (its shape and direction). The 'listener' would then guess which scene the other person was referring to, by selecting one of eight scenes on their own screen. Participants received points for every successful interaction (correct guesses). Participants paired up with a different person from their group at every new round, taking turns producing and guessing words.

At the start of the game, people would randomly guess meanings and make up new names. Over the course of several hours, participants started to combine words or part-words systematically, creating an actual mini-language.

For instance, in one group, 'wowo-ik' meant that a specific shape was going up and right, whereas 'wowo-ii' meant that the same shape was going straight up. With such a 'regular' system, it becomes easier to predict the meaning of new labels ('mop-ik' meant a different shape going up and right). Participants played in either 'small' groups of four participants or 'large' groups of eight participants. Would the large groups invent 'simpler' (more systematic) languages than the small groups?

Variability promotes structure

By the end of the experiment, the large groups had indeed created languages with more systematic grammars. "The pressure to create systematic languages is much higher in larger groups," explains Raviv. This is because there are more word versions in the larger groups. In order to understand each other, members of a large group must overcome this variability and develop systematic structure. So the more variability, the more it pushed people to make their language even simpler.

The researchers also found that the size of the group predicted how similar that group was to the other groups. All large groups reached similar levels of structure and communicative success. However, the small groups differed a lot from each other: some never developed systematic grammars, while others were very successful." This might mean that in the real world, larger languages are potentially more similar to each other than smaller languages," Raviv says.

"Our study shows that the social environment in which languages evolve, and specifically the number of people in the community, can affect the grammar of languages," concludes Raviv. "This could possibly explain why some languages have more complex grammar than others. The results also support the idea that an increase in human population size was one of the main drivers for the evolution of natural languages."

The study is published in the Proceedings of the Royal Society B: Biological Sciences.

Source: Max Planck Institute for Psycholinguistics [July 17, 2019]

Imitation breeds war in new evolutionary theory

By: Thomas Schmitt Attorney on June 29, 2019 / comment : 0 Anthropology, Human Evolution, Society

When anthropologists consider the origins of warfare, their evolutionary theories tend to boil it down to the resource-scarcity trifecta of food, territory and mates—three resources that would justify the loss of life and risk to a warring group of hunter-gatherers.

Credit: University of Colorado Denver

But researchers from University of Colorado Denver, University of British Columbia and University of Santiago, Chile, created an evolutionary mathematical model to unearth a fourth theory. They found that acculturation—the adoption and imitation of a victor's culture following defeat—could promote the evolution of intergroup conflicts. In other words, groups may evolve to fight for fighting's sake, despite the costs.

"Warriors" and "shepherds" in human evolution

"I've researched the evolution of cooperation and altruism—paradoxes in the conventional evolutionary theory of survival of the fittest—by group selection, but in this case, we wanted to understand the evolution of intergroup conflict," said Burton Simon, Ph.D., associate professor of mathematics at CU Denver, who has worked as a sort of "mathematical anthropologist" for the last decade.

The researchers' mathematical model is based on two classes of people: warriors, who specialize in intergroup conflicts and have a low birth rate, and shepherds, who cannot defend themselves but are highly reproductive. The amount of each within a group depended on the probability that an offspring becomes a warrior or shepherd, a cultural trait passed vertically from one generation to the next.

The study determined group dynamics through three types of events: group extinctions (a whole group dies, e.g., as the result of a drought or a bad crop), fissions (when an overly large group splits into two) and group conflicts due to their "belligerence" (assumed to increase a group's probability of trying to conquer another group). When groups fight in the model, the winner imposes its cultural traits on the loser or eliminates the group altogether. The belligerence of a group and the probability that they will impose their culture (acculturation tendency) are two of those traits.

"You need individuals who are shepherds to reproduce and individuals who are warriors to protect the group," said Simon. "But the right numbers of each can change over time in complicated and surprising ways."

Cultural evolution may promote the spread of conflict

How might these cultures thrive or die? Depending on the initial conditions of each group and which parameters (like acculturation and belligerence) were allowed to evolve, researchers found that sometimes groups fought each other into extinction. In other cases, the whole population reached a peaceful equilibrium.

But when researchers allowed all of the parameters to evolve, they found that acculturation coevolved with belligerence and warrior production. In other words, groups became more and more belligerent over time, and they forced their cultures on their victims instead of killing them.

That cultural evolution may promote the spread of conflict, even in cases where it may hurt both the groups and the individuals, is a theory that has received little attention. A mathematical model was one way to see how it could happen, said Simon.

"I realize mathematical anthropology sounds like an oxymoron," said Simon. "Most people who theorize about why there's so much conflict between human groups use economics and political science. But when you look at a hunter-gatherer society with a mathematical model, which forces you to state your assumptions precisely, the results can be enlightening."

Simon cautioned that the causes of today's conflicts are much too complex for a mathematical model to tackle, but his research is a glimpse into how imitation might indirectly breed conflict in evolutionary theory.

The study was published in the Proceedings of the National Academy of Sciences.

Author: Rachel Sturtz | Source: University of Colorado Denver [June 29, 2019]

New study shows how environmental disruptions affected ancient societies

By: Thomas Schmitt Attorney on June 18, 2019 / comment : 0 Archaeology, Climate Change, Earth Science, Society

LSU College of the Coast & Environment Distinguished Professor Emeritus John Day has collaborated with archeologists on a new analysis of societal development. They report that over the past 10,000 years, humanity has experienced a number of foundational transitions, or "bottlenecks." During these periods of transition, the advance or decline of societies was related to energy availability in the form of a benign climate and other factors.

Aerial view of the eruption of the volcano Grimsvotn in the south-east of Iceland [Credit: EPA/AdalSteinsson]

"Studying the factors that led to the advancement and contraction of past societies provides insight into how our globalized society might become more or less sustainable," Day said.

Day's collaborators include Joel Gunn of the University of North Carolina at Greensboro, William Folan of the Universidad Autonoma de Campeche in Mexico and Matthew Moerschbaecher of the Louisiana Oil Spill Coordinators Office. Gunn and Folan are Mayan archaeologists and Moerschbaecher is a graduate of LSU's oceanography program.

With the human population having exceeded the capacity of Earth's resources, this analysis suggests that a transition toward sustainability for the current energy-dense, globalized industrial society will be very difficult if not impossible without dramatic changes.

The authors say that these past transitions were caused by a combination of social, astronomical and biogeophysical events such as volcanic eruptions, changes in solar emissions, sea-level rise and ice volume, biogeochemical and ecological changes, and major social and technological innovations.

One example is the worldwide crisis that began in 536 AD, which was caused by three major volcanic eruptions within a decade. This event led to the destruction of half the population of Europe via the Black Death plague, starvation and wars. In China and the Mayan region, it led to crop failures, famine and plagues.

They found that when energy was abundant, societies expanded and prospered. Conversely, when energy sources declined, there was societal contraction and collapse. The previous example implies that changes are more likely to transpire due to planetary-scale disturbances and constraints, whether societal or environmental, and will likely lead to strong societal disruptions.

However, in the past, major changes sometimes moved toward a more sustainable social organization. For example, after one disruption, the Mayans switched to a more efficient use of energy and marine transportation and, at the time of European contact, they were leading a sustainable lifestyle.

The study appears in BioPhysical Economics and Resource Quality.

Source: Louisiana State University [June 18, 2019]

Modern economic theory explains prehistoric Mediterranean societies

By: Thomas Schmitt Attorney on May 10, 2019 / comment : 0 Anthropology, Society, Southern Europe

A Florida State University professor's research suggests a theory by famed economist Thomas Piketty on present-day wealth inequality actually explains a lot about how smaller-scale societies in the prehistoric Mediterranean developed.

Gold pendant from the Aegina treasure showing a Minoan nature god - the 'Master of Animals' [Credit: British Museum]

Piketty's theory says that high-growth economic conditions can slow the rate of wealth inequality and low-growth can accelerate it. In a new study, FSU Assistant Professor of Anthropology Thomas Leppard argues that certain hierarchical Mediterranean societies from about 3500 B.C. to 1000 B.C. fall into this low-growth context described by Piketty.

"Even though they never achieved the size and scale of societies in richer environments throughout the Old World, the fact that these Mediterranean societies developed in zones that were not prime for agriculture provided opportunities for some individuals to amass great wealth and social status compared to other individuals," Leppard said.

Because many of these societies were pre-monetary, wealth and growth rates can be approximated by agricultural production, particularly of large-scale, extensive farming of different grains.

"We know that agriculture was, to an extent, vital for the emergence of urban and 'state' societies," Leppard said.

Leppard argues that in larger, urban societies located in Mesopotamia, or near the Nile and the Yellow rivers, exaggerated income inequality took longer to occur because they were high-growth environments. This growth held off rapidly emergent wealth inequality and associated institutional hierarchies for longer, allowing these societies to coalesce at larger scales before durable hierarchies and state-type institutions appeared.

Piketty's theory, Leppard said, illustrates that very different conditions can drive similar social outcomes, and this challenges some current models in anthropological archaeology on how societal hierarchies developed.

"Ultimately, if very different processes can drive the appearance of societies that appear structurally similar, we're going to have to start thinking about multiple pathways to societies that we like to think of in one category," Leppard said.

Leppard's research is published in the journal Current Anthropology.

Author: Kathleen Haughney | Source: Florida State University [May 10, 2019]

How superstitions spread

By: Thomas Schmitt Attorney on April 18, 2019 / comment : 0 Anthropology, Society

Ancient Roman leaders once made decisions about important events, such as when to hold elections or where to build new cities, based on the presence or flight patterns of birds. Builders often omit the thirteenth floor from their floor plans, and many pedestrians go well out of their way to avoid walking under a ladder.

Do you change direction when you see a black cat approaching? A game theory-driven model developed by two theoretical biologists at Penn shows how such superstitions can catch on [Credit: iStock]

While it's widely recognized that superstitions like these are not rational, many persist, guiding the behavior of large groups of people even today.

In a new analysis driven by game theory, two theoretical biologists devised a model that shows how superstitious beliefs can become established in a society's social norms. Their work, which appears in Proceedings of the National Academy of Sciences, demonstrates how groups of individuals, each starting with distinct belief systems, can evolve a coordinated set of behaviors that are enforced by a set of consistent social norms.

"What's interesting here is that we show that, beginning in a system where no one has any particular belief system, a set of beliefs can emerge, and from those, a set of coordinated behaviors," says Erol Akçay, an assistant professor of biology at Penn.

"Slowly, these actors accumulate superstitions," adds Bryce Morsky, a postdoctoral researcher. "They may say, 'Ok, well I believe that when I observe this event I should behave this way because another person will behave that way,' and over time, if they have success in using that kind of a strategy, the superstitions catch on and can become evolutionarily stable."

Morsky and Akçay's work is an application of game theory, which attempts to predict how people will interact and make decisions in a social setting. They specifically considered what are known as correlated equilibria, scenarios in which all actors are given correlated signals that dictate their response to any given situation.

"A classic example is a traffic light," says Akçay. "If two people are approaching an intersection, one will get a 'stop' signal and one will get a 'go' signal and everybody knows that. It's rational for both parties to obey the light."

The signal, in this case the traffic light, is known as a correlating device, or more evocatively, a "choreographer." But the Penn team wanted to know what would happen if there was no choreographer. If people could pay attention to a variety of other signals that could direct their actions, and their beliefs were transmitted according to the success of their actions, would coordinated behaviors arise? In other words, can evolution act as a "blind choreographer?"

"What if a cyclist is riding toward an intersection, and instead of a traffic light they see a cat," Akçay says. "The cat is irrelevant to the intersection, but maybe the person decides that if they see a black cat, that means they should stop, or that maybe that means the approaching cyclist is going to stop."

Despite the color of a cat having no bearing on the likelihood of an approaching cyclist stopping or going, sometimes this kind of conditional strategy might result in a higher payoff to the cyclist—if it is correlated with superstitions of other cyclists.

"Sometimes it may be rational to hold these irrational beliefs," Morsky notes.

In their model, Morsky and Akçay assume that individuals are rational, in that they do not follow a norm blindly, but only do so when their beliefs make it seem beneficial. They change their beliefs by imitating successful people's beliefs. This creates an evolutionary dynamic where the norms "compete" against one another, rising and falling in prevalence through the group. This evolutionary process eventually leads to the formation of new social norms.

Morsky and Akçay showed that the evolutionarily stable norms, those that cannot be replaced by others, have to be consistent, meaning that they successfully coordinate individual behavior even in the absence of an external "choreographer. "

They found that these evolutionarily stable norms, in both prescribing how an actor should behave and also describing that actor's expectations of how others should behave, create a consistent belief system that helps coordinate the overall behavior of many actors, even if that coordination is not being directed by any outside choreographer.

To further explore their findings, the researchers hope to engage in social experiments to see whether individuals might start devising their own superstitions or beliefs when none are provided.

"What I like about this work," says Morsky, "is that these beliefs are made-up superstitions, but they become real because everybody actually follows them, so you create this social reality. I'm really interesting in testing that further."

Source: University of Pennsylvania [April 18, 2019]

Need for social skills helped shape modern human face

By: Thomas Schmitt Attorney on April 15, 2019 / comment : 0 Anthropology, Early Humans, Human Evolution, Society

The modern human face is distinctively different to that of our near relatives and now researchers believe its evolution may have been partly driven by our need for good social skills.

Skulls of hominins over the last 4.4 million years  [Credit: Rodrigo Lacruz]

As large-brained, short-faced hominins, our faces are different from other, now extinct hominins (such as the Neanderthals) and our closest living relatives (bonobos and chimpanzees), but how and why did the modern human face evolve this way?

A new review published in Nature Ecology and Evolution and authored by a team of international experts, including researchers from the University of York, traces changes in the evolution of the face from the early African hominins to the appearance of modern human anatomy.

They conclude that social communication has been somewhat overlooked as a factor underlying the modern human facial form. Our faces should be seen as the result of a combination of biomechanical, physiological and social influences, the authors of the study say.

The researchers suggest that our faces evolved not only due to factors such as diet and climate, but possibly also to provide more opportunities for gesture and nonverbal communication - vital skills for establishing the large social networks which are believed to have helped Homo sapiens to survive.

"We can now use our faces to signal more than 20 different categories of emotion via the contraction or relaxation of muscles", says Paul O'Higgins, Professor of Anatomy at the Hull York Medical School and the Department of Archaeology at the University of York. "It's unlikely that our early human ancestors had the same facial dexterity as the overall shape of the face and the positions of the muscles were different."

Instead of the pronounced brow ridge of other hominins, humans developed a smooth forehead with more visible, hairy eyebrows capable of a greater range of movement. This, alongside our faces becoming more slender, allows us to express a wide range of subtle emotions - including recognition and sympathy.

"We know that other factors such as diet, respiratory physiology and climate have contributed to the shape of the modern human face, but to interpret its evolution solely in terms of these factors would be an oversimplification," Professor O'Higgins adds.

The human face has been partly shaped by the mechanical demands of feeding and over the past 100,000 years our faces have been getting smaller as our developing ability to cook and process food led to a reduced need for chewing.

This facial shrinking process has become particularly marked since the agricultural revolution, as we switched from being hunter gatherers to agriculturalists and then to living in cities - lifestyles that led to increasingly pre-processed foods and less physical effort.

"Softer modern diets and industrialised societies may mean that the human face continues to decrease in size", says Professor O'Higgins. "There are limits on how much the human face can change however, for example breathing requires a sufficiently large nasal cavity."

"However, within these limits, the evolution of the human face is likely to continue as long as our species survives, migrates and encounters new environmental, social and cultural conditions."

Source: University of York [April 15, 2019]

Complex societies gave birth to big gods, not the other way around

By: Thomas Schmitt Attorney on March 20, 2019 / comment : 0 Anthropology, Religion, Society

An international research team, including a member of the Complexity Science Hub Vienna, investigated the role of "big gods" in the rise of complex large-scale societies. Big gods are defined as moralizing deities who punish ethical transgressions. Contrary to prevailing theories, the team found that beliefs in big gods are a consequence, not a cause, of the evolution of complex societies. The results are published in the current issue of the journal Nature.

Credit: Patrick Neufelder

For their statistical analyses the researchers used the Seshat: Global History Databank, the most comprehensive, and constantly growing collection of historical and prehistorical data. Currently Seshat contains about 300,000 records on social complexity, religion, and other characteristics of 500 past societies, spanning 10,000 years of human history.

"It has been a debate for centuries why humans, unlike other animals, cooperate in large groups of genetically unrelated individuals," says Seshat director and co-author Peter Turchin from the University of Connecticut and the Complexity Science Hub Vienna. Factors such as agriculture, warfare, or religion have been proposed as main driving forces.

One prominent theory, the big or moralizing gods hypothesis, assumes that religious beliefs were key. According to this theory people are more likely to cooperate fairly if they believe in gods who will punish them if they don't. "To our surprise, our data strongly contradict this hypothesis," says lead author Harvey Whitehouse. "In almost every world region for which we have data, moralizing gods tended to follow, not precede, increases in social complexity." Even more so, standardized rituals tended on average to appear hundreds of years before gods who cared about human morality.

Locations of the 30 sampled regions labelled according to precolonial evidence of moralizing gods. The area of each circle is proportional to social complexity of the earliest polity with moralizing gods to occupy the region or the latest precolonial polity for regions without precolonial moralizing gods. The numbers indicate the date of earliest evidence of such beliefs in thousands of years ago. The circles are colored by type of moralizing gods [Credit: (c) Harvey Whitehouse et al. 2019]

Such rituals create a collective identity and feelings of belonging that act as social glue, making people to behave more cooperatively. "Our results suggest that collective identities are more important to facilitate cooperation in societies than religious beliefs," says Harvey Whitehouse.

Until recently it has been impossible to distinguish between cause and effect in social theories and history, as standardized quantitative data from throughout world history were missing. To address this problem, data and social scientist Peter Turchin, together with Harvey Whitehouse and Pieter François from the University of Oxford, founded Seshat in 2011. The multidisciplinary project integrates the expertise of historians, archaeologists, anthropologists, social scientists as well as data scientists into a state-of-the-art, open-access database. Dozens of experts throughout the world helped to assemble detailed data on social complexity and religious beliefs and practices from hundreds of independent political units ("polities"), beginning with Neolithic Anatolians (today Turkey) in 9600 BCE.

The complexity of a society can be estimated by social characteristics such as population, territory, and sophistication of government institutions and information systems. Religious data include the presence of beliefs in supernatural enforcement of reciprocity, fairness, and loyalty, and the frequency and standardization of religious rituals.

Social complexity tends to increase more rapidly before the appearance of moralising gods, not after [Credit: Harvey Whitehouse et al. 2019]

"Seshat allows researchers to analyze hundreds of variables relating to social complexity, religion, warfare, agriculture and other features of human culture and society that vary over time and space," explains Pieter François. "Now that the database is ready for analysis, we are poised to test a long list of theories about human history." This includes competing theories of how and why humans evolved to cooperate in large-scale societies of millions and more people.

"Seshat is an unprecedented collaboration between anthropologists, historians, archaeologists, mathematicians, computer scientists, and evolutionary scientists", says Patrick Savage, corresponding author of the article. "It shows how big data can revolutionize the study of human history."

Source: Complexity Science Hub Vienna [March 20, 2019]

New research reveals humanity's roles in ecosystems

By: Thomas Schmitt Attorney on February 17, 2019 / comment : 0 Anthropology, Ecosystems, Environment, Society, Wildlife

In two back-to-back symposia at the annual meeting of the American Association for the Advancement of Science in Washington, D.C., on Sunday, Feb. 17 at 1:30 and 3:30 PM respectively, a cross-disciplinary cohort of scientists will present the first comprehensive investigations of how humans interacted with plant and animal species in different cultures worldwide through time. By compiling and comparing detailed data from pre-industrial and modern societies, the researchers are sketching a picture of humans' roles and impacts in sustainable and unsustainable socio-ecological systems.

In this depiction of the nearshore food web of Sanak Island, Alaska, spheres represent species or groups of species, and the links between them show feeding relationships. The colors of the spheres indicate types of taxa: green shows algae; blue shows seagrass, lichen, protozoa, bacteria, and detritus; yellow shows invertebrates such as snails,  crabs, mussels, and octopus; orange shows fishes; purple shows birds; and red shows mammals such as sea otters. The red node near the center top of the image represents human hunter-gatherers (Aleut). It is the first comprehensive food web to include Homo sapiens [Credit: J.A. Dunne]

"Almost all food webs that have been compiled and studied have been put together without including humans," says Jennifer Dunne (Santa Fe Institute), an ecologist and complex systems scientist who is leading the project with archaeologist Stefani Crabtree (Santa Fe Institute and Center for Research and Interdisciplinarity). "It takes a lot of time and effort to put these kinds of detailed data together. So even though ecologists have been studying food webs for decades, we're only now in a position where we can start to rigorously compare human roles and impacts across different systems to understand sustainability in new kinds of ways," says Dunne.

What do we learn when we do include humans?

As part of her presentation during the second symposium, Dunne will reveal initial results from a comparison of food webs that explicitly include humans across several socioecological systems. Three are pre-industrial systems -- the Aleutian Islands of Alaska, the Pueblo U.S. Southwest, and the Western Desert of Australia, and one is modern -- the Tagus Estuary of Portugal. Given the diversity of cultures, ecologies, climates, and time periods represented in the data, Dunne suggests that we can start to learn "something more general about human roles in, and impacts on, ecosystems" by comparing these systems. For example, humans are often super-generalists compared to other predators -- they feed on a huge variety of different species.

In some systems, humans as super-generalist predators can fit into ecosystems without causing extinctions or major environmental degradation. For example, according to Dunne's pioneering analysis published in Scientific Reports in 2016, the Sanak Island (Alaska) Aleut fed on a whopping 122 of 513 taxa in the nearshore marine ecosystem. However, like other predators, they switched from their favorite prey -- sea lions -- to shellfish, kelp, or whatever was readily available when the weather did not allow them to hunt in open water. "Prey-switching is very stabilizing for food webs," Dunne explains, "because it allows prey taxa populations to recover from exploitation, as the predator's focus shifts to other prey that are easier to forage or hunt given current conditions." That, plus limited use of hunting technology and other factors helped to minimize potential negative impacts of humans on the Sanak ecosystem -- during approximately 7,000 years of human habitation, there is no evidence for any long-term local extinctions.

Scientific study reveals the enigmas on social behaviour of western lowland gorillas

By: Thomas Schmitt Attorney on February 06, 2019 / comment : 0 Anthropology, Congo, Genetics, Society, Wildlife

A new study published in the journal Proceedings of the Royal Society B: Biological Sciences reveals one of the enigmas related to the social behaviour of the western lowland gorilla (Gorilla gorilla gorilla) in the heart of the African equatorial rainforest. These primates show a dynamic social structure - individuals change frequently between families - with a high degree of tolerance and peaceful coexistence among the members, according to the new article which counts on the participation of the experts José Domingo Rodríguez Teijeiro, Magdalena Bermejo, Guillem Molina-Vacas, from the Faculty of Biology and the Biodiversity Research Institute of the University of Barcelona (IRBio).

The social behaviour of the western lowland gorilla can impact the transmission of diseases  in this endangered species [Credit: Germán Illera]

According to the authors, this social behaviour may have played an important role in the evolutionary story of the species, easing the exchange of information and a better exploitation of trophic resources. However, this social dynamics may have worsened the impact of some infectious diseases in the population of gorillas, experts warn. In this context, epidemic Ebola virus outbreaks, which affected the primate population in Congo between 2002 and 2004, caused the disappearance of 95 % of this ape, causing this species to be in critical danger of extinction according to the Red List of threatened species by the International Union for the Conservation of Nature (IUCN).

In the new study, carried out in the Ngaga Forest in the Republic of the Congo, counts on the participation of German Illera (Great Apes Conservation/Research Odzala-Lossi and SPAC gGmbH, Republic of the Congo), Giovanni Forcina, Rubén Bernardo-Madrid, Eloy Revilla and Carles Vilà (Doñana Biological Station EBD-CSIC) and other experts of the University of Rennes (France).

After the western lowland gorillas in the heart of the forest

The ecology and behaviour of the western lowland gorilla inside the equatorial forests was an enigma so far. Since the first scientific studies started, differences between the behaviour of these two African primates were known: the western lowland gorilla (Gorilla gorilla gorilla) -living in rainforests around the basin of the River Congo- and the mountain gorilla (Gorilla gorilla beringei), a better studied primate in the volcanic mountainsides of the African Rift. At the moment, hunting and epidemics endanger the survival of wild populations of these primates which share more than 98% of genetic material with the human species.

Unlike the mountain gorilla, which has aggressive and infrequent interactions between families, the western lowland gorilla was known to have frequent and peaceful interaction between members of the families. However, due a low visibility inside the forests, western lowland gorillas that had been studied in bais, typical open clearings which are the meeting point for families of the species to feed from plants rich in mineral salts.

As part of the study, the experts conducted a scientific monitoring over five years to three families of the western lowland gorilla in the same heart of the Congo forest. According to the conclusions, interaction between individuals from different families is common and peaceful so the individuals eat and play together with no signs of aggression.

Regarding methodology, experts profiled an image of the social structure and parentage relations of more than 120 gorillas through the genetic analysis of faeces samples taken over four months -in families and single individuals- in the Ngaga forest.

A dynamic social structure with no records of infanticides

Data show families have a dynamic social structure in which individuals conduct frequent changes among family groups. Young individuals are usually outside the family and enter temporarily other family groups in which they have no close relatives. This social behaviour could be linked to the lack of infanticide records in this species, experts note.

This new study shows the image of a modular society featured by the existence of strong ties which do not avoid the transfer of individuals between different families and a high degree of tolerance between their members. The results of this study show the importance of complementing in situ monitoring studies with non-invasive genetic analysis to find the structure and social dynamics in animal species which are hard to have access to. At the same time, conclusions highlight the importance of social behaviour in disease transmission and the development of effective conservation strategies in the long run.

Source: University of Barcelona [February 06, 2019]

There is no scientific proof that war is ingrained in human nature, according to study

By: Thomas Schmitt Attorney on December 04, 2018 / comment : 0 Anthropology, Early Humans, Society

Is it in our nature to go to war? Should we just accept the fact that humans have this innate tendency and are hardwired to kill members of other groups?

Rock paintings in Tadrart Acacus region of Libya dated from 12,000 BC to 100 AD [Credit: WikiCommons]

No, says R. Brian Ferguson, professor of anthropology at Rutgers University-Newark. There is no scientific proof that we have an inherent propensity to take up arms and collectively kill.

In a study published in Scientific American, Ferguson argues that war may not be in our nature at all. People might fight and sometimes kill for personal reasons, but homicide, he argues, is not war.

"There is definitely controversy in the field when it comes to this question," says Ferguson, who studies human nature, war and peace. "But it is the overall circumstances that we live in that creates the impulse to go or not go to war."

In his study, "War May Not Be in Our Nature After All. Why We Fight", Ferguson reached back thousands of years to look at the historical roots of warfare to shed light on whether humans have always made war or if armed conflict has only emerged as changing social conditions provided the motivation and organization to collectively kill.

It's a topic he's been studying since the Vietnam War, a period in history that sparked his interest. His research is an attempt to settle an age-old academic debate over whether humans are hardwired to fight wars or if war is a human invention. If war is not ingrained in human nature, that may help provide a basis for arguing against war as an option, he says.

Many scientists and scholars believe that humans as a species are aggressive, brutal and bloodthirsty and this behavior is part of our DNA. Ferguson argues, however, that there is no real indication or scientific proof that humans have been waging war for the entire history of the species.

"Warlike cultures in some places became common only over the past 10,000 years and in most place more recently than that," Ferguson says.

In his research, Ferguson looked at cases reported as violent deaths throughout the prehistoric record. He found that 15 percent to 25 percent of deaths that many anthropologists and archeologists say were the result of war may reflect cherry-picking the most violent cases, which are contradicted by broad surveys of all archaeological sites.

"Individual killing is not the same as war on social groups," says Ferguson. "War leaves physical traces that archaeologists can find. When and where it began is very different in different places around the world, but there are stretches of even thousands of years when there are no clear signs of war."

Part of the reason for the debate, Ferguson says, is that the evidence used to identify prehistoric warfare – weapons, art and cave paintings, defensive structures and skeletal remains – are often ambiguous and difficult to interpret. Careful examination of all evidence typically finds no strong indication of war in early remains, which changes to clear signs of war in later periods.

He disputes the belief of many scholars that humans may have inherited their genetic makeup from their chimpanzee cousins millions of years ago. After examining every reported chimpanzee killing, Ferguson, who is writing a book on the subject, believes that war among chimps was not an evolved evolutionary strategy but rather a response to human contact and disturbances.

So why did war become so common in more recent archaeological finds? Ferguson says that preconditions that made war more likely became far more widespread, including social hierarchy, a more sedentary existence, a growing regional population, valuable resources and the establishment of boundaries. These conditions have sometimes worsened with severe environmental changes, he says.

Ferguson, who also studies contemporary war, brutal civil wars around the world and U.S. wars in Iraq and Afghanistan, agrees with anthropologist Margaret Mead that "warfare is only an invention, not a biological necessity," but does he not see war ending.

"Anthropologists think about prospects for war in the long term," Ferguson says. "If the idea that war is part of human nature is not scientifically supported, alternative futures open up. If more people work for prevention, the eventual eradication of war is a definite theoretical possibility."

Source: Rutgers University [December 04, 2018]