People around the world like the same kinds of smell

What smells we like or dislike is primarily determined by the structure of the particular odour molecule. A collaborative study involving researchers from Karolinska Institutet, Sweden, and the University of Oxford, UK, shows that people share odour preferences regardless of cultural background. The study is published in the journal Current Biology.

"We wanted to examine if people around the world have the same smell perception and like the same types of odour, or whether this is something that is culturally learned," says Artin Arshamian, researcher at the Department of Clinical Neuroscience, Karolinska Institutet. "Traditionally it has been seen as cultural, but we can show that culture has very little to do with it."

The present study shows that the structure of the odour molecule determines whether a smell is considered pleasant or not. The researchers found that certain smells were liked more than others regardless of the cultural affiliation of participants.

"Cultures around the world rank different odours in a similar way no matter where they come from, but odour preferences have a personal -- although not cultural -- component," says Dr Arshamian.

Studied indigenous populations

The study was made possible through an international network of researchers that collaborated in a unique combination of experimental methods and field studies. The network comprised researchers from Karolinska Institutet, Lund University and Stockholm University (Sweden), University of Oxford and University College London (UK), Arizona State University, Monell Chemical Senses Center and the University of Pennsylvania (USA), Universidad San Francisco de Quito (Ecuador), University of Melbourne (Australia) and National Autonomous University of Mexico.

Many of the researchers are field workers working with indigenous populations. For this present study, the researchers selected nine communities representing different lifestyles: four hunter-gatherer groups and five groups with different forms of farming and fishing. Some of these groups have very little contact with Western foodstuffs or household articles.

Disparate odiferous environments

"Since these groups live in such disparate odiferous environments, like rainforest, coast, mountain and city, we capture many different types of 'odour experiences'," says Dr Arshamian.

The study included a total of 235 individuals, who were asked to rank smells on a scale of pleasant to unpleasant. The results show variation between individuals within each group, but global correspondence on which odours are pleasant and unpleasant. The researchers show that the variation is largely explained by molecular structure (41 per cent) and by personal preference (54 per cent).

"Personal preference can be due to learning but could also be a result of our genetic makeup," says Dr Arshamian.

Vanilla was considered most pleasant

The odours the participants were asked to rank included vanilla, which smelled best then followed by ethyl butyrate, which smells like peaches. The smell that most participants considered the least pleasant was isovaleric acid, which can be found in many foods, such as cheese, soy milk and apple juice, but also in foot sweat.

According to Dr Arshamian, a possible reason why people consider some smells more pleasant than others regardless of culture is that such odours increased the chances of survival during human evolution.

"Now we know that there's universal odour perception that is driven by molecular structure and that explains why we like or dislike a certain smell," Dr Arshamian continues. "The next step is to study why this is so by linking this knowledge to what happens in the brain when we smell a particular odour."

Read more at Science Daily

The origin and legacy of the Etruscans

The Etruscan civilization, which flourished during the Iron Age in central Italy, has intrigued scholars for millennia. With remarkable metallurgical skills and a now-extinct, non-Indo-European language, the Etruscans stood out from their contemporary neighbors, leading to intense debate from the likes of the ancient Greek historian Herodotus on their geographical origins.

Now, a new study by a team of scholars from Germany, Italy, USA, Denmark and the UK, sheds light on the origin and legacy of the enigmatic Etruscans with genome-wide data from 82 ancient individuals from central and southern Italy, spanning 800 BCE to 1000 CE. Their results show that the Etruscans, despite their unique cultural expressions, were closely related to their italic neighbors, and reveal major genetic transformations associated with historical events.

An intriguing phenomenon

With an extinct language that is only partly understood, much of what was initially known about Etruscan civilization comes from the commentary of later Greek and Roman writers. One hypothesis about their origins, the one favored by Herodotus, points to the influence of ancient Greek cultural elements to argue that the Etruscans descended from migrating Anatolian or Aegean groups. Another, championed by Dionysius of Halicarnassus, proposes that the Etruscans originated and developed locally from the Bronze Age Villanovan culture and were therefore an autochthonous population.

Although the current consensus among archaeologists supports a local origin for the Etruscans, a lack of ancient DNA from the region has made genetic investigations inconsistent. The current study, with a time transect of ancient genomic information spanning almost 2000 years collected from 12 archaeological sites, resolves lingering questions about Etruscan origins, showing no evidence for a recent population movement from Anatolia. In fact, the Etruscans shared the genetic profile of the Latins living in nearby Rome, with a large proportion of their genetic profiles coming from steppe-related ancestry that arrived in the region during the Bronze Age.

Considering that steppe-related groups were likely responsible for the spread of Indo-European languages, now spoken around the world by billions of people, the persistence of a non-Indo-European Etruscan language is an intriguing and still unexplained phenomenon that will require further archaeological, historical, linguistic and genetic investigation.

"This linguistic persistence, combined with a genetic turnover, challenges simple assumptions that genes equal languages and suggests a more complex scenario that may have involved the assimilation of early Italic speakers by the Etruscan speech community, possibly during a prolonged period of admixture over the second millennium BCE," says David Caramelli, Professor at the University of Florence.

Periods of change

Despite a few individuals of eastern Mediterranean, northern African, and central Europeanorigins, the Etruscan-related gene pool remained stable for at least 800 years, spanning the Iron Age and Roman Republic period. The study finds, however, that during the subsequent Roman Imperial period, central Italy experienced a large scale genetic shift, resulting from admixture with eastern Mediterranean populations, which likely included slaves and soldiers relocated across the Roman Empire.

"This genetic shift clearly depicts the role of the Roman Empire in the large-scale displacement of people in a time of enhanced upward or downward socioeconomic and geographic mobility," says Johannes Krause, Director at the Max Planck Institute for Evolutionary Anthropology.

Looking at the more recent Early Middle Ages, the researchers identified northern European ancestries spreading across the Italian peninsula following the collapse of the Western Roman Empire. These results suggest that Germanic migrants, including individuals associated with the newly established Longobard Kingdom, might have left a traceable impact on the genetic landscape of central Italy.

In the regions of Tuscany, Lazio, and Basilicata the population's ancestry remained largely continuous between the Early Medieval times and today, suggesting that the main gene pool of present-day people from central and southern Italy was largely formed at least 1000 years ago.

Although more ancient DNA from across Italy is needed to support the above conclusions, ancestry shifts in Tuscany and northern Lazio similar to those reported for the city of Rome and its surroundings suggests that historical events during the first millennium CE had a major impact on the genetic transformations over much of the Italian peninsula.

Read more at Science Daily

Central European prehistory was highly dynamic

Centrally located along trade routes and tightly nestled around the important waterways such as the Elbe River, Bohemia attracted many different archaeological cultures, rendering it a key region in understanding the prehistory of Europe. In addition to the expansions associated with the spread of agriculture and "steppe"-related ancestry previously discovered, this new study identifies at least another three migratory events which shaped central European prehistory.

The genetic profiles of people associated with Funnelbeaker and Globular Amphora cultures show evidence of being recent migrants to the region. This finding shows that the period between arrival of agriculture and "steppe"-related ancestry, hitherto thought of as an uneventful period, was more dynamic than previously hypothesised.

Drastic changes to the genetic landscape

The large sample size of the study, particularly concentrated on the Late Neolithic and Early Bronze Age (~6,000-3,700 years ago), also allowed novel insights into social processes to be made. Individuals associated with the Corded Ware culture expanded from Eastern Europe and then assimilated preferentially central European women into their culture, giving them the same burial ritual as members of the immigrating group. "We were finally able to fill key temporal gaps, especially in the transition period around 5,000 years ago, when we see the genetic landscape changing drastically," says Max Planck researcher Wolfgang Haak, senior author and principal investigator of the study. "Intriguingly, in this early horizon we find individuals with high amounts of 'steppe' ancestry next to others with little or none, all buried according to the same customs."

Once established, individuals of the Corded Ware culture (4,900-4,400 years ago) changed genetically through time. One important change seems to have been the sharp decline in Y-chromosome lineage diversity. Although initially carrying five different Y-lineages, later Corded Ware males carry almost exclusively only a single lineage, essentially being descended from the same man in the recent past. "This pattern may reflect the emergence of a new social structure or regulation of mating in which only a subset of men fathered the majority of offspring," says first author Luka Papac, a researcher at the Max Planck Institute for the Science of Human History.

This social structure seems to have been even stricter in the following Bell Beaker society (4,500-4,200 years ago) where every single male sampled belonged to a single, newly introduced Y-lineage. Remarkably, this Bell Beaker Y-lineage is never seen before in Bohemia, implying that a new clan arrived in the region and almost immediately replaced all pre-existing Y-lineages with not a single lineage from Corded Ware or previous societies found among Bell Beaker males.

Cultural, biological, and social changes

The Early Bronze Age Unetice culture has traditionally been thought of descending from Bell Beaker individuals, with perhaps limited input from the southeast (Carpathian Basin). However, the new genetic data supports yet another genetic turnover originating from regions northeast of Bohemia. Remarkably, also 80 percent of the early Unetice Y-lineages are new to Bohemia, some of which are previously found in individuals from north-eastern Europe, providing clues to where they originated from. "This finding was very surprising to us archaeologists as we did not expect to see such clear patterns, even though the region has played a critical role, e.g. in the emerging trade of amber from the Baltic and became an important trading hub during the Bronze and Iron Ages," adds co-author and co-PI Michal Ernée from the Czech Academy of Sciences.

Read more at Science Daily

Cultural biases impact native fish, too

From art to religion to land use, much of what is deemed valuable in the United States was shaped centuries ago by the white male perspective. Fish, it turns out, are no exception.

A study published in Fisheries Magazine, a journal of the American Fisheries Society, explores how colonialist attitudes toward native fishes were rooted in elements of racism and sexism. It describes how those attitudes continue to shape fisheries management today, often to the detriment of native fishes.

The study, led by the University of California, Davis, with Nicholls State University and a national team of fisheries researchers, found that nearly all states have policies that encourage overfishing native species. The study maintains that the term "rough fish" is pejorative and degrading to native fish.

"That has bothered me for a long time," said lead author Andrew Rypel, co-director of the Center for Watershed Sciences and the Peter B. Moyle and California Trout Chair in Coldwater Fish Ecology at UC Davis. He and others have been disturbed by images of "glory killings" of native fish that periodically pop up on the internet, as well as the lump categorization of less preferred species as "rough" or "trash" fish.

"When you trace the history of the problem, you quickly realize it's because the field was shaped by white men, excluding other points of view," Rypel said. "Sometimes you have to look at that history honestly to figure out what to do."

The study offers several recommendations for how anglers and fisheries managers can shift to a new paradigm that's more inclusive and beneficial to all fish and people.

A 'rough' start

The term "rough fish" dates to commercial riverboat fishing in the mid-late 1800s. Slow, heavy boats would lighten their loads by "rough-dressing" -- removing organs but not filleting -- less desirable species and discarding them. Biologists came to use the term to describe an unsubstantiated idea that native fish limit game fish species historically desired by Europeans. That attitude posed a major threat to many native species, which were killed in large numbers.

For instance, the alligator gar, an ancient species that can grow more than 8 feet long and weigh 300 pounds, was particularly persecuted in the past century. Called a "wolf among fishes," poison, dynamite and electrocution were used to greatly reduce its population. But now some fishers spend thousands of dollars for the opportunity to catch and release a giant gar. In 2021, Minnesota changed its statute to describe gar as a "game fish" rather than a "rough fish."

Co-author Solomon David has helped fuel renewed appreciation for gar and its relative, bowfin. He runs the GarLab at Nicholls State University in Louisiana, where he is an assistant professor. He said many native fishes, such as suckers and gars, have long been valued by Indigenous people and people of color.

"European colonists heavily influenced what fishes were more valuable, often the species that looked more similar to what they're used to," David said. "So trout, bass and salmon got their value while many other native species got pushed to the wayside."

Limited view

The study authors conducted a survey of fishing regulations across the United States to compare policies and bag limits on "rough fish" with those of largemouth bass, a ubiquitous sport fish.

"When I was a kid fishing, you might go to the river with a worm and catch all these interesting species," Rypel said. "The guidebook would just say 'rough fish, bag unlimited.' Not much has changed since I was kid."

The study found that no states had bag limits rivaling those for the bass. While black basses were often managed at five fish per day, regulations for most native fishes were extremely liberal. Forty-three states had unlimited bag limits for at least one native species. In the remaining states, bag limits were between 15 and 50 fish a day.

Freshwater ecosystems are threatened by pollution, habitat loss and climate change. Up to half of fish species globally are in some form of decline, and 83 percent of native California fish species are declining. Native fishes help ecosystems in many ways, including nutrient cycling and food chain support for other native species. The authors pointedly call for a "rewrite" in managing them.

Recommendations

The study's recommendations for that rewrite include:
 

• Stop saying "rough fish." They suggest "native fish" as a simple alternative.
• Integrate Indigenous perspectives into fisheries management.
• Revisit species bag limits. Lower bag limits for native species until the science is conducted to confirm they could be higher. The study takes particular note of the fast-growing bowfishing market that has contributed to removing native species.
• Support science on native fishes. Game fish receive 11 times more research and management attention in American Fisheries Society journals than do "rough fish." To learn the true value of native fishes, more research is required.
• Co-manage species that have co-evolved, such as freshwater mussels and fish that host them.
• Correct misinformation and enhance science educationthrough outreach and education for all ages.

"We have a chance to redirect fisheries science and conservation and expand it with respect for biodiversity and diversity," David said. "It's been a long time coming. Change is slow, but we have an opportunity here, and we should take advantage of it."

Read more at Science Daily

The cerebellum may have played an important role in the evolution of the human brain

The cerebellum -- a part of the brain once recognized mainly for its role in coordinating movement -- underwent evolutionary changes that may have contributed to human culture, language and tool use. This new finding appears in a study by Elaine Guevara of Duke University and colleagues, published May 6th in the journal PLOS Genetics.

Scientists studying how humans evolved their remarkable capacity to think and learn have frequently focused on the prefrontal cortex, a part of the brain vital for executive functions, like moral reasoning and decision making. But recently, the cerebellum has begun receiving more attention for its role in human cognition. Guevara and her team investigated the evolution of the cerebellum and the prefrontal cortex by looking for molecular differences between humans, chimpanzees, and rhesus macaque monkeys. Specifically, they examined genomes from the two types of brain tissue in the three species to find epigenetic differences. These are modifications that do not change the DNA sequence but can affect which genes are turned on and off and can be inherited by future generations.

Compared to chimpanzees and rhesus macaques, humans showed greater epigenetic differences in the cerebellum than the prefrontal cortex, highlighting the importance of the cerebellum in human brain evolution. The epigenetic differences were especially apparent on genes involved in brain development, brain inflammation, fat metabolism and synaptic plasticity -- the strengthening or weakening of connections between neurons depending on how often they are used.

The epigenetic differences identified in the new study are relevant for understanding how the human brain functions and its ability to adapt and make new connections. These epigenetic differences may also be involved in aging and disease. Previous studies have shown that epigenetic differences between humans and chimpanzees in the prefrontal cortex are associated with genes involved in psychiatric conditions and neurodegeneration. Overall, the new study affirms the importance of including the cerebellum when studying how the human brain evolved.

 Read more at Science Daily

Human portraits reveals shift in culture, cognition

Throughout history, portraits featuring the human profile have evolved to reflect changing cultural norms. A new study led by Helena Miton, a Santa Fe Institute Omidyar Fellow, and co-authored by Dan Sperber of Central European University and Miko?aj Hernik, of UiT the Artic University of Norway, shows that human cognition plays a critical role in the evolution of human portraiture.

"These cognitive factors cause greater spontaneous attention to what is in front of -- rather than behind -- a subject, Miton says. "Scenes with more space in front of a directed object are both produced more often and judged as more aesthetically pleasant. This leads to the prediction that, in profile-oriented human portraits, compositions with more space in front of depicted subjects (a 'forward bias') should be over-represented."

To test their prediction, the research team looked at 1831 paintings by 582 unique European painters from the 15th to the 20th century. They not only found evidence that this forward bias -- where painters put more open space in front of their sitters than behind them -- was widespread, they also found evidence that the bias became stronger when cultural norms of spatial composition favoring centering became less stringent.

In the accompanying image, the portrait on the left (Adrian Brouwer, 1630) is an example of a composition with the sitter centered. On the right, a portrait by Pierre Auguste Renoir (1905) shows the forward bias, with more free space in front of the sitter than behind her. The study showed this type of spatial composition increased over time.

"Culture and cognition are two interacting domains," Miton explains. "With most cultural phenomena, you're going to have some kind of influence from cognition. Our idea is to work out how we identify these factors and how we work with that type of causality."

The research team identified cultural norms that favored centering portraits, especially in the earlier periods. These preferences clearly loosened over time, resulting in more diverse portrait composition.

The widespread presence of a forward bias was robust. Previous studies found some evidence of a forward bias in the production of a handful of painters, but these results suggest that this bias in spatial composition was widespread -- particularly remarkable since it goes against a cultural norm that favors centering sitters.

According to Miton, this research approach can be extended to quantify in a more general way (and with a more general painting data set) how much artistic norms loosen and how much variation increases over time. Beyond the art world, the approach can also look at the role cognition plays in other cultural phenomena, from writing systems to medical practices.

Read more at Science Daily

Cultural diversity in chimpanzees

The transmission of cultures from generation-to-generation is only found in a few species besides humans. Chimpanzees are one such species and exhibit a large diversity of cultural and tool use behaviours. Although these behaviours have been well documented at a handful of long term research sites, the true cultural repertoire of chimpanzees across populations is still poorly understood. To better understand this diversity, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, initiated the 'Pan African Programme: The Cultured Chimpanzee' (PanAf) in 2010. Using a standardized protocol, researchers set up camera traps, collected samples and recorded ecological data at over 40 temporary and long-term research sites across Africa.

Prior to this study, termite fishing was thought to occur in only two forms with one or multiple tools, from either above-ground or underground termite nests. By carefully observing the techniques required to termite fish at ten different sites, lead author Christophe Boesch created a catalogue of behaviours (ethogram) for each chimpanzee in the study.

What was found was 38 different technical elements making up the various termite fishing techniques, all of which were combined in different ways in each of the chimpanzee communities. In addition, individuals in the same community shared more of the termite fishing technical elements, and unique combinations of the technical elements, when compared to chimpanzees from other groups.

Surprising diversity

"The diversity of techniques seen in chimpanzee termite fishing was a huge surprise to me. Not only does each community have a very unique way of fishing, they also combine a number of different elements into specific termite fishing etiquettes," explains Christophe Boesch."The most striking examples of this are how the Wonga Wongue chimpanzees of Gabon usually lie down on their sides to termite fish, while the Korup chimpanzees in Cameroon lean on their elbows, and the ones from Goualougo in the Republic of Congo sit while fishing."

Because the communities of chimpanzees live in similar habitats with access to the same resources, ecological differences could mostly be ruled out to explain the observed differences. "This supports the idea that chimpanzees are capable of imitating social techniques in 'how to termite fish' which goes beyond alternative explanations such as each individual reinventing termite fishing each time they learn it," explains co-author Ammie Kalan.

Conforming to the group
Much like in human etiquette, not everything is about increased efficiency but rather about conforming to what the rest of the group is doing. In humans, this is observed in the different chopstick cultures across Asia. "For example, in Thailand and Japan not only are chopsticks somehow shaped differently, but the way they hold them differ as well, and this is very reminiscent of what we see here with chimpanzees. In La Belgique in Cameroon, chimpanzees fashion their stick by opening the fibers to obtain a long brush and then rest the termite-covered stick on their wrist while they eat. On the other hand, at another site in Cameroon called Korup, the chimpanzees do not make a brush at all and use their mouth to shake the inserted stick while it is in the mound," explains Christophe Boesch.

In humans, cultural variation has been documented in hundreds of different populations which is one explanation for why chimpanzee culture seems so limited in comparison. "What we knew before about chimpanzees came from at most 15 communities," notes co-author Hjalmar Kuehl. "Through the PanAf we have been able to study many more communities and by this we are able to learn more about the richness of chimpanzee diversity and culture and could demonstrate that there is so much more to discover out there."

Read more at Science Daily

Disappearance of animal species takes mental, cultural and material toll on humans

For thousands of years, indigenous hunting societies have subsisted on specific animals for their survival. How have these hunter-gatherers been affected when these animals migrate or go extinct?

To answer this and other questions, Tel Aviv University (TAU) researchers conducted a broad survey of several hunter-gatherer societies across history in a retrospective study published on January 30 in Time and Mind. The study, led by Eyal Halfon and Prof. Ran Barkai of TAU's Department of Archeology and Ancient Near Eastern Cultures, sheds new light on the deep, multidimensional connection between humans and animals.

"There has been much discussion of the impact of people on the disappearance of animal species, mostly through hunting," explains Halfon. "But we flipped the issue to discover how the disappearance of animals -- either through extinction or migration -- has affected people."

The research reveals that these societies expressed a deep emotional and psychological connection with the animal species they hunted, especially after their disappearance. The study will help anthropologists and others understand the profound environmental changes taking place in our own lifetimes.

Halfon and Prof. Barkai conducted a survey of different historical periods and geographical locations, focusing on hunter-gatherer societies that hunted animals as the basis for their subsistence. They also investigated situations in which these animals became extinct or moved to more hospitable regions as a result of climate change.

"We found that humans reacted to the loss of the animal they hunted -- a significant partner in deep, varied and fundamental ways," Halfon says.

The new research explores hunter-gatherer societies throughout human history, from those dating back hundreds of thousands of years to modern-day societies that still function much the way prehistoric groups did. Ten case studies illustrate the deep connection -- existential, physical, spiritual and emotional -- between humans and animals they hunted.

"Many hunter-gatherer populations were based on one type of animal that provided many necessities such as food, clothing, tools and fuel," Prof. Barkai says. "For example, until 400,000 years ago prehistoric humans in Israel hunted elephants. Up to 40,000 years ago, residents of Northern Siberia hunted the woolly mammoth. When these animals disappeared from those areas, this had major ramifications for humans, who needed to respond and adapt to a new situation. Some had to completely change their way of life to survive."

According to the study, human groups adapted in different ways. Siberian residents seeking sustenance after the disappearance of mammoths migrated east and became the first settlers of Alaska and northern Canada. Cave dwellers in central Israel's Qesem Cave (excavated by Prof. Barkai) hunted fallow deer, far smaller than elephants, which required agility and social connections instead of robust physical strength. This necessitated far-reaching changes in their material and social culture and, subsequently, physical structure.

Halfon stresses the emotional reaction to an animal group's disappearance. "Humans felt deeply connected to the animals they hunted, considering them partners in nature, and appreciating them for the livelihood and sustenance they provided," he says. "We believe they never forgot these animals -- even long after they disappeared from the landscape."

An intriguing example of this kind of memory can be found in engravings from the Late Paleolithic period in Europe, which feature animals like mammoths and seals. Studies show that most of these depictions were created long after these two animals disappeared from the vicinity.

"These depictions reflect a simple human emotion we all know very well: longing," says Halfon. "Early humans remembered the animals that disappeared and perpetuated them, just like a poet who writes a song about his beloved who left him."

Read more at Science Daily

Ostrich eggshell beads reveal 10,000 years of cultural interaction across Africa

Ostrich eggshell beads are some of the oldest ornaments made by humankind, and they can be found dating back at least 50,000 years in Africa. Previous research in southern Africa has shown that the beads increase in size about 2,000 years ago, when herding populations first enter the region. In the current study, researchers Jennifer Miller and Elizabeth Sawchuk investigate this idea using increased data and evaluate the hypothesis in a new region where it has never before been tested.

Review of old ideas, analysis of old collections

To conduct their study, the researchers recorded the diameters of 1,200 ostrich eggshell beads unearthed from 30 sites in Africa dating to the last 10,000 years. Many of these bead measurements were taken from decades-old unstudied collections, and so are being reported here for the first time. This new data increases the published bead diameter measurements from less than 100 to over 1,000, and reveals new trends that oppose longstanding beliefs.

The ostrich eggshell beads reflect different responses to the introduction of herding between eastern and southern Africa. In southern Africa, new bead styles appear alongside signs of herding, but do not replace the existing forager bead traditions. On the other hand, beads from the eastern Africa sites showed no change in style with the introduction of herding. Although eastern African bead sizes are consistently larger than those from southern Africa, the larger southern African herder beads fall within the eastern African forager size range, hinting at contact between these regions as herding spread. "These beads are symbols that were made by hunter-gatherers from both regions for more than 40,000 years," says lead author Jennifer Miller, "so changes -- or lack thereof -- in these symbols tells us how these communities responded to cultural contact and economic change."

Ostrich eggshell beads tell the story of ancient interaction

The story told by ostrich eggshell beads is more nuanced than previously believed. Contact with outside groups of herders likely introduced new bead styles along with domesticated animals, but the archaeological record suggests the incoming influence did not overwhelm existing local traditions. The existing customs were not replaced with new ones; rather they continued and incorporated some of the new elements.

In eastern Africa, studied here for the first time, there was no apparent change in bead style with the arrival of herding groups from the north. This may be because local foragers adopted herding while retaining their bead-making traditions, because migrant herders possessed similar traditions prior to contact, and/or because incoming herders adopted local styles. "In the modern world, migration, cultural contact, and economic change often create tension," says Sawchuk, "ancient peoples experienced these situations too, and the patterns in cultural objects like ostrich eggshell beads give us a chance to study how they navigated these experiences."

The researchers hope that this work inspires a renewed interest into ostrich eggshell beads, and recommend that future studies present individual bead diameters rather than a single average of many. Future research should also investigate questions related to manufacture, chemical identification, and the effects of taphonomic processes and wear on bead diameter. "This study shows that examining old collections can generate important findings without new excavation," says Miller, "and we hope that future studies will take advantage of the wealth of artifacts that have been excavated but not yet studied."

From Science Daily

Perception of musical pitch varies across cultures

People who are accustomed to listening to Western music, which is based on a system of notes organized in octaves, can usually perceive the similarity between notes that are same but played in different registers -- say, high C and middle C. However, a longstanding question is whether this a universal phenomenon or one that has been ingrained by musical exposure.

This question has been hard to answer, in part because of the difficulty in finding people who have not been exposed to Western music. Now, a new study led by researchers from MIT and the Max Planck Institute for Empirical Aesthetics has found that unlike residents of the United States, people living in a remote area of the Bolivian rainforest usually do not perceive the similarities between two versions of the same note played at different registers (high or low).

The findings suggest that although there is a natural mathematical relationship between the frequencies of every "C," no matter what octave it's played in, the brain only becomes attuned to those similarities after hearing music based on octaves, says Josh McDermott, an associate professor in MIT's Department of Brain and Cognitive Sciences.

"It may well be that there is a biological predisposition to favor octave relationships, but it doesn't seem to be realized unless you are exposed to music in an octave-based system," says McDermott, who is also a member of MIT's McGovern Institute for Brain Research and Center for Brains, Minds and Machines.

The study also found that members of the Bolivian tribe, known as the Tsimane', and Westerners do have a very similar upper limit on the frequency of notes that they can accurately distinguish, suggesting that that aspect of pitch perception may be independent of musical experience and biologically determined.

McDermott is the senior author of the study, which appears in the journal Current Biology on Sept. 19. Nori Jacoby, a former MIT postdoc who is now a group leader at the Max Planck Institute for Empirical Aesthetics, is the paper's lead author. Other authors are Eduardo Undurraga, an assistant professor at the Pontifical Catholic University of Chile; Malinda McPherson, a graduate student in the Harvard/MIT Program in Speech and Hearing Bioscience and Technology; Joaquin Valdes, a graduate student at the Pontifical Catholic University of Chile; and Tomas Ossandon, an assistant professor at the Pontifical Catholic University of Chile.

Octaves apart

Cross-cultural studies of how music is perceived can shed light on the interplay between biological constraints and cultural influences that shape human perception. McDermott's lab has performed several such studies with the participation of Tsimane' tribe members, who live in relative isolation from Western culture and have had little exposure to Western music.

In a study published in 2016, McDermott and his colleagues found that Westerners and Tsimane' had different aesthetic reactions to chords, or combinations of notes. To Western ears, the combination of C and F# is very grating, but Tsimane' listeners rated this chord just as likeable as other chords that Westerners would interpret as more pleasant, such as C and G.

Later, Jacoby and McDermott found that both Westerners and Tsimane' are drawn to musical rhythms composed of simple integer ratios, but the ratios they favor are different, based on which rhythms are more common in the music they listen to.

In their new study, the researchers studied pitch perception using an experimental design in which they play a very simple tune, only two or three notes, and then ask the listener to sing it back. The notes that were played could come from any octave within the range of human hearing, but listeners sang their responses within their vocal range, usually restricted to a single octave.

Western listeners, especially those who were trained musicians, tended to reproduce the tune an exact number of octaves above or below what they heard, though they were not specifically instructed to do so. In Western music, the pitch of the same note doubles with each ascending octave, so tones with frequencies of 27.5 hertz, 55 hertz, 110 hertz, 220 hertz, and so on, are all heard as the note A.

Western listeners in the study, all of whom lived in New York or Boston, accurately reproduced sequences such as A-C-A, but in a different register, as though they hear the similarity of notes separated by octaves. However, the Tsimane' did not.

"The relative pitch was preserved (between notes in the series), but the absolute pitch produced by the Tsimane' didn't have any relationship to the absolute pitch of the stimulus," Jacoby says. "That's consistent with the idea that perceptual similarity is something that we acquire from exposure to Western music, where the octave is structurally very important."

The ability to reproduce the same note in different octaves may be honed by singing along with others whose natural registers are different, or singing along with an instrument being played in a different pitch range, Jacoby says.

Limits of perception

The study findings also shed light on the upper limits of pitch perception for humans. It has been known for a long time that Western listeners cannot accurately distinguish pitches above about 4,000 hertz, although they can still hear frequencies up to nearly 20,000 hertz. In a traditional 88-key piano, the highest note is about 4,100 hertz.

People have speculated that the piano was designed to go only that high because of a fundamental limit on pitch perception, but McDermott thought it could be possible that the opposite was true: That is, the limit was culturally influenced by the fact that few musical instruments produce frequencies higher than 4,000 hertz.

The researchers found that although Tsimane' musical instruments usually have upper limits much lower than 4,000 hertz, Tsimane' listeners could distinguish pitches very well up to about 4,000 hertz, as evidenced by accurate sung reproductions of those pitch intervals. Above that threshold, their perceptions broke down, very similarly to Western listeners.

"It looks almost exactly the same across groups, so we have some evidence for biological constraints on the limits of pitch," Jacoby says.

One possible explanation for this limit is that once frequencies reach about 4,000 hertz, the firing rates of the neurons of our inner ear can't keep up and we lose a critical cue with which to distinguish different frequencies.

Jacoby and McDermott now hope to expand their cross-cultural studies to other groups who have had little exposure to Western music, and to perform more detailed studies of pitch perception among the Tsimane'.

Such studies have already shown the value of including research participants other than the Western-educated, relatively wealthy college undergraduates who are the subjects of most academic studies on perception, McDermott says. These broader studies allow researchers to tease out different elements of perception that cannot be seen when examining only a single, homogenous group.

Read more at Science Daily

Cultural drive breeds war in new evolutionary theory

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.

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.

The study, "Acculturation drives the evolution of intergroup conflict," was published June 21 in the journal PNAS.

"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, PhD, associate professor of mathematics at the University of Colorado 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."

Read more at Science Daily

78,000 year cave record from East Africa shows early cultural innovations

Worked red ochre; bead made of a sea shell; ostrich eggshell beads; bone tool; close-up of the bone tool showing traces of scraping. (from left to right).

An international, interdisciplinary group of scholars working along the East African coast have discovered a major cave site which records substantial activities of hunter-gatherers and later, Iron Age communities. Detailed environmental research has demonstrated that human occupations occur in a persistent tropical forest-grassland ecotone, adding new information about the habitats exploited by our species, and indicating that populations sought refuge in a relatively stable environment. Prior to this cave excavation, little information was available about the last 78,000 years from coastal East Africa, with the majority of archaeological research focused on the Rift Valley and in South Africa.

Humans lived in the humid coastal forest

A large-scale interdisciplinary study, including scientific analyses of archaeological plants, animals and shells from the cave indicates a broad perseverance of forest and grassland environments. As the cave environment underwent little variation over time, humans found the site attractive for occupation, even during periods of time when other parts of Africa would have been inhospitable. This suggests that humans exploited the cave environment and landscape over the long term, relying on plant and animal resources when the wider surrounding landscapes dried. The ecological setting of Panga ya Saidi is consistent with increasing evidence that Homo sapiens could adapt to a variety of environments as they moved across Africa and Eurasia, suggesting that flexibility may be the hallmark of our species. Homo sapiens developed a range of survival strategies to live in diverse habitats, including tropical forests, arid zones, coasts and the cold environments found at higher latitudes.

Technological innovations occur at 67,000 years ago

Carefully prepared stone tool toolkits of the Middle Stone Age occur in deposits dating back to 78,000 years ago, but a distinct shift in technology to the Later Stone Age is shown by the recovery of small artefacts beginning at 67,000 years ago. The miniaturization of stone tools may reflect changes in hunting practices and behaviors. The Panga ya Saidi sequence after 67,000, however, has a mix of technologies, and no radical break of behavior can be detected at any time, arguing against the cognitive or cultural 'revolutions' theorized by some archaeologists. Moreover, no notable break in human occupation occurs during the Toba volcanic super-eruption of 74,000 years ago, supporting views that the so-called 'volcanic winter' did not lead to the near-extinction of human populations, though hints of increased occupation intensity from 60,000 years ago suggests that populations were increasing in size.

Earliest symbolic and cultural items found at Panga ya Saidi cave

The deep archaeological sequence of Panga ya Saidi cave has produced a remarkable new cultural record indicative of cultural complexity over the long term. Among the recovered items are worked and incised bones, ostrich eggshell beads, marine shell beads, and worked ochre. Panga ya Saidi has produced the oldest bead in Kenya, dating to ~65,000 years ago. At about 33,000 years ago, beads were most commonly made of shells acquired from the coast. While this demonstrates contact with the coast, there is no evidence for the regular exploitation of marine resources for subsistence purposes. Ostrich eggshell beads become more common after 25,000 years ago, and after 10,000 years ago, there is again a shift to coastal shell use. In the layers dating to between ~48,000 to 25,000 years ago, carved bone, carved tusk, a decorated bone tube, a small bone point, and modified pieces of ochre were found. Though indicative of behavioral complexity and symbolism, their intermittent appearance in the cave sequence argues against a model for a behavioral or cognitive revolution at any specific point in time.

Project Principal Investigator and Director of the Department of Archaeology at the Max Planck Institute for the Science of Human History Dr. Nicole Boivin states, "The East African coastal hinterland and its forests and have been long considered to be marginal to human evolution so the discovery of Panga ya Saidi cave will certainly change archaeologists' views and perceptions."

Group Leader of the Stable Isotopes Lab Dr. Patrick Roberts adds, "Occupation in a tropical forest-grassland environment adds to our knowledge that our species lived in a variety of habitats in Africa."

Read more at Science Daily

Earthquake faults may have played key role in shaping the culture of ancient Greece

The Ancient Greeks may have built sacred or treasured sites deliberately on land previously affected by earthquake activity, according to a new study by the University of Plymouth.

Professor of Geoscience Communication Iain Stewart MBE, Director of the University's Sustainable Earth Institute, has presented several BBC documentaries about the power of earthquakes in shaping landscapes and communities.

Now he believes fault lines created by seismic activity in the Aegean region may have caused areas to be afforded special cultural status and, as such, led to them becoming sites of much celebrated temples and great cities.

Scientists have previously suggested Delphi, a mountainside complex once home to a legendary oracle, gained its position in Classical Greek society largely as a result of a sacred spring and intoxicating gases which emanated from a fault line caused by an earthquake.

But Professor Stewart believes Delphi may not be alone in this regard, and that other cities including Mycenae, Ephesus, Cnidus and Hierapolis may have been constructed specifically because of the presence of fault lines.

Professor Stewart said: "Earthquake faulting is endemic to the Aegean world, and for more than 30 years, I have been fascinated by the role earthquakes played in shaping its landscape. But I have always thought it more than a coincidence that many important sites are located directly on top of fault lines created by seismic activity. The Ancient Greeks placed great value on hot springs unlocked by earthquakes, but perhaps the building of temples and cities close to these sites was more systematic than has previously been thought."

In the study, published in Proceedings of the Geologists' Association, Professor Stewart says a correspondence of active faults and ancient cities in parts of Greece and western Turkey might not seem unduly surprising given the Aegean region is riddled with seismic faults and littered with ruined settlements.

But, he adds, many seismic fault traces in the region do not simply disrupt the fabric of buildings and streets, but run straight through the heart of the ancient settlements' most sacred structures.

There are prominent examples to support the theory, such as in Delphi itself where a sanctuary was destroyed by an earthquake in 373BC only for its temple to be rebuilt directly on the same fault line.

There are also many tales of individuals who attained oracular status by descending into the underworld, with some commentators arguing that such cave systems or grottoes caused by seismic activity may have formed the backdrop for these stories.

Read more at Science Daily