Evolution During Human Colonizations: Selective Advantage of Being There First

Research published in Science Nov. 3 reveals that the first individuals settling on new land are more successful at passing on their genes than those who did not migrate. According to Dr. Damian Labuda at the University of Montréal and Sainte-Justine Hospital, the study suggests that population expansion creates opportunities for natural selection to act.

The findings come from the utilization of a unique research infrastructure, the BALSAC population database which allows the reconstruction of the structure of the Quebec population over four centuries. In this research the descending lineages of all couples married in the Charlevoix-Saguenay Lac St-Jean region between 1686 and 1960 were analyzed. This genealogy comprises more than 1 million individuals.

Dr. Laurent Excoffier, University of Berne and Swiss Institute of Bioinformatics, Dr. Damian Labuda, and Dr. Hélène Vézina, Projet BALSAC, Université du Québec à Chicoutimi, who led the study, together with research associates Claudia Moreau, Michèle Jomphe and Ph.D. student Claude Bhérer, investigated the demographic history of this region to investigate the effects of rapid territorial and demographic expansion on the dynamics of colonization and human evolution.

"We find that families who are at the forefront of a range expansion into new territories had greater reproductive success. In other words, that they had more children, and more children who also had children," Labuda explained. "As a result, these families made a higher genetic contribution to the contemporary population than those who remained behind in what we call the range core, as opposed to the wave front.

The research confirms in humans a phenomenon that has already been observed in other species with much shorter generation spans. "We knew that the migration of species into new areas promoted the spread of rare mutations through a phenomenon known as 'gene surfing', but now we find that selection at the wave front could make this surfing much more efficient," Excoffier said. This evolutionary mechanism in combination with founder effects and social or cultural transmission of reproductive behavior could explain why some genetic diseases are found at an elevated frequency in the Charlevoix and Saguenay Lac Saint-Jean regions where the study was carried out, as rare mutations can also surf during a range expansion.

"It is exciting to see how a study on a regional population of Quebec can bring insight on a human process that has been going on for thousands of years. The BALSAC population is a powerful tool for social and genetic research and this study is a very nice demonstration of its possibilities," Vézina said.

The researchers also note that, although their study concerns a whole human population spread over several centuries, it only represents a short period of human evolution at a limited geographical scale. It thus appears difficult to directly generalize these results obtained in a farmer population to what happened during other range expansions, especially considering the differences between the ecological demography of hunter-gatherer and farmer communities. But given the highly successful history of the human colonization of our planet, it appears very likely that a considerable fraction of our ancestors have lived on the edge of expansion waves. Consequently, several human traits favoring dispersal and reproduction could have evolved during phases of range expansions rather than resulting from selection in constant environments.

Read more at Science Daily

Britain's oldest family business opened when Henry VIII ruled

RJ Balson and Sons, a butchers based in Bridport, Dorset, boasts an astonishing history that is almost 500 years old.

Experts have traced the businesses roots back through 25 generations to when founder John Balson opened a stall in the town's market on South Street in 1535.

Since then dozens of family members have worked as butchers in the market town, passing their skills down the generations.

And 476 years later, the shop remains a thriving business and has been named Britain's oldest family run retailer.

At that time Henry VIII was still married to Anne Boleyn, the first complete English language translation of the Bible was printed in Antwerp by William Tynedale and Miles Coverdale, and Peru, the Galapagos Islands and Quebec were discovered.

It has been in its present location since 1880, not far from its orginal location.

According to the Institute for Family Business, this makes it the oldest continuously trading family business in Britain.

The firm sells its produce, including 20 varieties of sausages such as els, boar and ostrich,l all over the world, with a large customer base in America.

It also sells exotic fare such as pheasants and guinea fowl but has remained close to its traditional roots.

Until recently the store's owner was Donald Balson, who died this year aged 88.

He said earlier this year: "The love of the job, which has been passed down from generation to generation, is one of the main reasons we have been successful."

His son Richard Balson, 54, said on Thursday: "It's not always gone directly from father to son - sometimes it's gone to a brother and sons but it has been in the family all the time and in January, my son will come into the business to run the online side.

"He's got a son too, so hopefully it'll keep on going. We started up just before the Mary Rose sank just short of Portsmouth harbour.

Read more at The Telegraph

Ancient Chinese Coin Brought Good Luck in Yukon

The discovery of a puzzling 340-year-old coin etched with traditional Chinese characters in Canada's Yukon territory suggests that the area was already aflurry with trading even before the Gold Rush.

Minted during the Qing Dynasty reign of Emperor Kangxi, the coin is 60 percent copper and 40 percent zinc. It was cast between 1667 and 1671 -- long before the 1898 gold rush, when people from all over the world headed to Dawson City and the Klondike gold fields.

The coin adds to an intriguing small collection of ancient Chinese coinage discovered in Yukon near gold rush trails.

"Overall, three Chinese coins have been found in the Yukon Territory," expedition leader James Mooney, from Ecofor Consulting Ltd., told Discovery News.

While one dates from 1724 and 1735, a third coin, unearthed in 1993 near a gold rush trail by Beaver Creek, is surprisingly older.

"This coin was thought to date from 1880 to 1910 and to be associated with a Klondike era use of a trading trail," Mooney said.

But fact-checking following the new discovery revealed that the coin dated from between 1403 and 1424.

"This age overlaps with a controversial theory of worldwide exploration by Chinese explorers, and only begs more questions," Mooney said.

The three ancient Chinese coins are round with a square hole in the center, but the newly found coin has four additional small holes above each corner of the central square.

"The vast majority of these Chinese 'cash coins' did not have additional holes drilled into them," Gary Ashkenazy, an expert in old Chinese coins, told Discovery News.

However, coins of certain emperors were considered to be particularly auspicious and were treated as amulets or charms.

"Additional holes were drilled in these coins so that they could be attached to a house ridgepole, door or gate in order to provide protection. They were also sewn onto clothing as a means to protect a person from ghosts and evil spirits," Ashkenazy said

The Yukon coin was likely used this way since it was cast during the long reign of Emperor Kangxi.

"These coins are considered lucky because kang means health and xi means prosperous. Also, Emperor Kangxi reigned for more than 60 years so his name is associated with longevity," Ashkenazy said.

Chinese people collected coins cast from each of the 20 mints which operated during the reign of Emperor Kangxi. Put on a string in a certain order to form a sort of poem, the coins were carried as amulets for good luck.

A Ming Dynasty coin unearthed in 1993 in a travel corridor near a Yukon gold trail, may have also been a good luck charm, according to Ashkenazy. Cast between 1403 and 1424 during the reign of Emperor Cheng Zu, it featured the inscription yong le tong bao, meaning "happiness forever."

Although it cannot be ruled out that the ancient coins were brought into Yukon by gold diggers who carried them as family amulets, Mooney believes that they are evidence of extensive pre-gold rush trading.

Found at a spot overlooking a river that would have made a good campsite, the 17th-century coin likely reached the remote wilderness of Yukon through "Russian and coastal Tlingit trade intermediaries," Mooney said.

The coin would have been brought back by Russians when they traded furs from North American wildlife to the Chinese in exchange for their goods.

Known to have occurred as early as the mid-1700s, Russian trade along the Pacific Northwest also involved the native Tlingit people.

The Russians traded glass beads, silk, coinage and other goods from China with the Tlingit in exchange for furs, such as sea otter, seal, beaver, fox and marten.

Read more at Discovery News

Dino-Era Disaster: Multiple Drowned Toothy Birds

Bones, eggs and eggshells are all that's left of a Transylvania Dinosaur-Era bird colony that made the mistake of nesting next to a big river, which wound up drowning the avian clan.

The discovery, made in the Sebes area of Transylvania, Romania, represents the first known nest colony for any Upper Cretaceous bird, according to a presentation today at the Society of Vertebrate Paleontology's 71st Annual Meeting in Las Vegas.

The birds were enantiornithines, which retained toothed beaks and had claws on their hands. Scientists now know these birds were colonial, waterside nesters, a common habit typically seen in modern birds that eat aquatic plants or animals.

Co-author Darren Naish, a vertebrate paleontologist at the University of Southampton, told Discovery News that the birds "would have looked peculiar to modern eyes." In addition to their toothiness, they had "a heavier looking tail."

The frozen-in-time avian disaster scene suggests that the birds were enjoying a peaceful end to the nesting period, with some hatchlings and their parents already in the process of leaving, when everything suddenly changed.

"Because the fossil assemblage consists only of eggshell fragments, eggs and bird bones, it is most likely that the flooding was actually a quick 'swamping' or 'drowning' where the water from the river rose by, say, a foot or two," Naish said, explaining that "it was not a massive tidal wave-style event, but most like a tidal bore-style flooding."

The fossils show that some adults were swept up by the water and drowned. Baby bird bones suggest remaining chicks died too.

"The water sweeping across the colony picked up broken eggshell, any remaining eggs and birds, and carried them a few meters across to a shallow depression, perhaps present on the other side of the colony," where the researchers found the remains buried under layers of sediment.

Gareth Dyke, who is also a vertebrate paleontologist at the University of Southampton, worked with Naish, Matyas Vremir, and other researchers on the excavation.

Dyke told Discovery News that such findings are extremely rare, since “only a handful of undisputed, isolated Cretaceous eggs are known.” He added that the Romanian scene contains “the first fossil evidence for a breeding colony of Mesozoic birds.”

Before the flooding at the site, known as Hatzeg Basin, the scene must have been quite tranquil.

"We should imagine hundreds of closely spaced individuals of these birds sitting on their nests, flying off a few times during the day to bathe or feed near or in the river," Naish said. "Seeing as colonial nesting is known in non-avian dinosaurs as well as in modern birds, its discovery in Mesozoic birds isn’t necessarily a surprise, but it’s nice to have it confirmed."

Read more at Discovery News

Evolution Offers Clues to Leading Cause of Death During Childbirth

Unusual features of the human placenta may be the underlying cause of postpartum hemorrhage, the leading cause of maternal deaths during childbirth, according to evolutionary research at the University of Illinois at Chicago.

Defined as the loss of more than a pint of blood during or just after vaginal delivery, postpartum hemorrhage accounts for nearly 35 percent, or 125,000, of the 358,000 worldwide annual maternal deaths during childbirth.

Despite its prevalence, the causes of postpartum hemorrhage are unknown, says Julienne Rutherford, assistant professor of oral biology at UIC, who along with Elizabeth Abrams, assistant professor of anthropology, co-authored a theoretical synthesis published in the journal American Anthropologist. While common in humans, postpartum hemorrhage is rare in other mammals, including nonhuman primates.

"Understanding the underlying cause of the increased risk of postpartum hemorrhage in humans is a critical step toward discovering new treatments and eventually preventing it on a global scale," Rutherford said.

Previous studies on postpartum hemorrhage have focused on how it can be treated and on recognizing its associated risk factors, Abrams said. Less has been done to discover its cause.

In humans, the invasiveness of the placenta into the uterine wall and the subsequent takeover of maternal blood vessels appear to be greater than in nonhumans, Rutherford said. This suggests a link between placental invasiveness early in pregnancy and blood loss at delivery, when the placenta separates from the uterine wall.

Research by Abrams and Rutherford suggests that hormones produced by trophoblasts -- cells formed during the first stage of pregnancy that provide nutrients to the embryo and develop into a large part of the placenta, and that guide the interaction with the uterus -- may provide an early predictor of risk.

"Biomarkers of postpartum hemorrhage that could be used early in pregnancy would allow women to make informed decisions about their choice of birthing site and medical care based on their risk," Abrams said. This biomarker hypothesis has not yet been studied.

Many women in poor countries don't give birth in hospitals or clinics, said Abrams, who has conducted research on childbirth in the sub-Saharan countries of Malawi and Tanzania. By the time postpartum bleeding occurs, it may be too late to reach a health center.

In a normal birth, the placenta begins to separate from the uterine wall before delivery. Bleeding at the site is normally stopped by the constriction of blood vessels due to the contraction and retraction of uterine muscles. Hemorrhage can occur weeks after birth, but most deaths occur within four hours of delivery.

There are two major risk factors for postpartum hemorrhage, said Rutherford. The leading factor is uterine contractions that are too weak to stop bleeding. The cause of this is unclear, but it could delay delivery of the placenta -- which is the other known risk factor, she said. The best predictor for any woman is previous postpartum hemorrhage, "which has disturbing implications for women in resource-poor settings," Abrams said.

Understanding how the human placenta differs from that of other primates is a new approach, and according to Abrams and Rutherford, it is one that might help explain the mechanisms underlying risk factors in humans.

Read more at Science Daily

NASA Studying Ways to Make 'Tractor Beams' a Reality

Tractor beams -- the ability to trap and move objects using laser light -- are the stuff of science fiction, but a team of NASA scientists has won funding to study the concept for remotely capturing planetary or atmospheric particles and delivering them to a robotic rover or orbiting spacecraft for analysis.

The NASA Office of the Chief Technologist (OCT) has awarded Principal Investigator Paul Stysley and team members Demetrios Poulios and Barry Coyle at NASA's Goddard Space Flight Center in Greenbelt, Md., $100,000 to study three experimental methods for corralling particles and transporting them via laser light to an instrument -- akin to a vacuum using suction to collect and transport dirt to a canister or bag. Once delivered, an instrument would then characterize their composition.

"Though a mainstay in science fiction, and Star Trek in particular, laser-based trapping isn't fanciful or beyond current technological know-how," Stysley said. The team has identified three different approaches for transporting particles, as well as single molecules, viruses, ribonucleic acid, and fully functioning cells, using the power of light.

"The original thought was that we could use tractor beams for cleaning up orbital debris," Stysley said. "But to pull something that huge would be almost impossible -- at least now. That's when it bubbled up that perhaps we could use the same approach for sample collection."

With the Phase-1 funding from OCT's recently reestablished NASA Innovative Advanced Concepts (NIAC) program designed to spur the development of "revolutionary" space technologies, the team will study the state of the technology to determine which of the three techniques would apply best to sample collection. OCT received hundreds of proposals, ultimately selecting only 30 for initial funding.

Replace Current Sample-Collection Methods

Currently, NASA uses a variety of techniques to collect extraterrestrial samples. With Stardust, a space probe launched in 1999, the Agency used aerogel to gather samples as it flew through the coma of comet Wild 2. A capsule returned the samples in 2006. NASA's next rover to Mars, Curiosity, will drill and scoop samples from the Martian surface and then carry out detailed analyses of the materials with one of the rover's many onboard instruments, including the Goddard-built Sample Analysis at Mars instrument suite.

"These techniques have proven to be largely successful, but they are limited by high costs and limited range and sample rate," Stysley said. "An optical-trapping system, on the other hand, could grab desired molecules from the upper atmosphere on an orbiting spacecraft or trap them from the ground or lower atmosphere from a lander. In other words, they could continuously and remotely capture particles over a longer period of time, which would enhance science goals and reduce mission risk."

Team to Study Three Approaches

One experimental approach the team plans to study -- the optical vortex or "optical tweezers" method -- involves the use of two counter-propagating beams of light. The resulting ring-like geometry confines particles to the dark core of the overlapping beams. By alternately strengthening or weakening the intensity of one of the light beams -- in effect heating the air around the trapped particle -- researchers have shown in laboratory testing that they can move the particle along the ring's center. This technique, however, requires the presence of an atmosphere.

Another technique employs optical solenoid beams -- those whose intensity peaks spiral around the axis of propagation. Testing has shown that the approach can trap and exert a force that drives particles in the opposite direction of the light-beam source. In other words, the particulate matter is pulled back along the entire beam of light. Unlike the optical vortex method, this technique relies solely on electromagnetic effects and could operate in a space vacuum, making it ideal for studying the composition of materials on one of the airless planetary moons, for example.

Read more at Science Daily

Zombie Volcano or New Supervolcano?

A broad swath of the Altiplano plateau in southwest Bolivia is inflating like a giant balloon, presumably as magma builds up deep underground. This aggressive rise hints that a new supervolcano could be awakening in South America, geologists say, and so they are keen to learn more about the underlying cause.

So far, they know the inflation is surprisingly fast: the center of the patch has risen 7.9 inches (20 centimeters) in the past 20 years. What is more, the uplift extends about 43 miles (70 kilometers) across -- similar in size to the caldera that formed in the wake of the latest eruption of the Yellowstone supervolcano, which blanketed half of the U.S. in ash 640,000 years ago.

At the center of all recent intrigue is Uturuncu, a nearly 20,000-foot (6,000 meter) ancient volcano long given up for dead. Based on the spewage from its last eruption, 300,000 years ago, it would not qualify as a supervolcano on its own. (Its peers are far tamer, including Mount St. Helens in Washington state). But Uturunca could be drawing magma from a dense swarm of nearby volcanoes, many of which are currently active.

The big question is how much magma has accumulated so far. Based on Uturunca’s rate of inflation, scientists calculated the magma chamber has been growing by about 27 cubic feet (1 cubic meter) per second. But for how long? Amassing magma at that rapid clip for thousands of years would make for a serious amount of fuel for an eruption. Or maybe its only just begun gathering steam. The rate measurements are based on satellite data the go back only 20 years.

Geologists Noah Finnegan and Jonathan Perkins of the University of California, Santa Cruz, spent several weeks in Boliva last November to get a sense for Uturunca’s long-term history by tracing the shifting shorelines and deltas of ancient lakes. If the volcano’s summit had been rising as rapidly over the past several thousand years, it would gradually lift a side of the lakes.

“Because the uplift of Uturuncu is more pronounced in the center and tapers out toward the edges, that produces an uplift gradient, which is what will cause the lakes to tilt,” Perkins told Discovery News. “It’s kind of like having a jack in the center that slowly ramps up the topography over geologic time.”

The pair’s preliminary findings, which they reported at the annual meeting of the Geological Society of America in October, indicate that the expansion probably started only recently, and so the magma chamber probably has not yet grown to supervolcanic proportions. (For comparison, the chamber seething underneath Yellowstone is at least 200 miles deep and 400 miles east to west.)

Read more at Discovery News

Saber-Toothed Squirrel Lived Near Dinosaurs

Northern Patagonia was once home to a squirrel-like mammal with extremely long canine teeth, a petite 4 to 6-inch-long body, a narrow muzzle and a rounded skull, according to a paper in the latest issue of Nature.

You won't see this critter stealing birdfood in your garden because it lived more than 100 million years ago when dinosaurs were still thriving. As you can see from the above image, dinos must have been no strangers to this saber-toothed animal that might have spent its days darting around columnar dino legs.

The discovery breaks a prior gap of about 60 million years in the fossil record for South American mammals.

University of Louisville paleontologist Guillermo Rougier and co-authors Sebastián Apesteguía and Leandro Gaetano named the new animal Cronopio dentiacutus. It is a dryolestoid, an extinct group of animals distantly related to today's marsupials and placentals.

"It looks somewhat like 'Scrat,' the saber-toothed squirrel from 'Ice Age,'" Rougier was quoted as saying in a UofL press release. He's a professor of anatomy and neurobiology there.

Real life is often more bizarre than fiction.

"The new dryolestoid, Cronopio, is without a doubt one of the most unusual mammals that I have seen, extinct or living," said John Wible, curator of mammals at the Carnegie Museum of Natural History.

The researchers found skulls of the Scrat-like animals embedded in rock in a remote area of northern Patagonia, about 100 miles from the city of Allen in the Argentinian province of Rio Negro. It took the team several years of patient lab work to remove the specimens from the rocks.

"We knew it was important, based on the age of the rocks and because we found skulls," Rougier said. “Usually we find teeth or bone fragments of this age. Most of what we know of early mammals has been determined through teeth because enamel is the hardest substance in our bodies and survives well the passage of time; it is usually what we have left to study."

"The skull, however, provides us with features of the biology of the animal," he continued, "making it possible for us to determine this is the first of its kind dating to the early Late Cretaceous period in South America. This time period in South America was somewhat of a blank slate to us. Now we have a mammal as a starting point for further study of the lineage of all mammals, humans included."

A lot of paleontologist eyes are now on South America.

"… Until now, all we have had are isolated teeth and a few jaw fragments … which don't really help much in deciphering broader relationships," said Rich Cifelli, presidential professor of zoology at the University of Oklahoma and a researcher, who, like Rougier, has spent his career discovering and identifying mammal remains.

Read more at Discovery News

'Zombie' Worms Found in Mediterranean Fossil

Traces of bizarre, bone-eating 'zombie' worms have been found on a 3-million-year-old fossil whale bone from Tuscany in Italy. It is the first time the genus Osedax has been found in the Mediterranean, and suggests Osedax were widespread throughout the world's oceans 6 million years ago.

The new find, published in the journal Historical Biology, confirms what scientists have long suspected -- that Osedax were likely responsible for erasing parts of the fossil record by destroying bones before they could become fossils.

Worms from the Osedax genus do not have a mouth or gut but consume the bone by growing root-like tissues, which dissolve the bone as they grow.

Lead scientist Nicholas Higgs discovered tell-tale traces of Osedax in the Mediterranean last year using micro-CT (Computed Tomography) scanning technology as part of his PhD at the University of Leeds and the Natural History Museum.

He says: "After several promising leads came to a dead end, the scans from the final sample looked different and I knew that I was on to something."

Osedax were first discovered alive in 2002 in Monterey Bay, California, where they were living on the bones of a decaying gray whale.

Since then, scientists have been curious about how the worms might have affected fossil records, but understanding when Osedax evolved and where they lived in the past has until now remained a problem because actual remains of soft-bodied Osedax do not preserve as fossils.

The only way to tell where and when Osedax have been at work is by distinctive bulb-shaped cavities that they leave behind in a bone -- and it is these borings that have finally been recognised by Higgs.

His research shows how widespread Osedax were millions of years ago.

The only other known evidence of Osedax from the past is in whale bones from the Pacific coast of Washington State in the US -- about as far away as it is possible to get from the Mediterranean in terms of ocean connectedness.

When Mediterranean dried up almost six million years ago most deep sea animals were killed. About half a million years later the sea re-flooded from the Atlantic.

Higgs says: "So finding out that Osedax were feeding on this whale bone three million years ago tell us that their ancestors must have also been living in the Atlantic as well, because the Mediterranean was re-colonised 5.5 million years ago from the Atlantic."

It is now almost certain that the Mediterranean is currently host to undiscovered, living Osedax species, Higgs says.

"There are 20 different species in Monterey, California alone, so it's almost certain there are many more out there. If Osedax were living the Mediterranean three million years ago there's no reason why they aren't living there now."

Read more at Science Daily

Early time-telling instrument up for auction

The 14th century time-telling device, which carries the badge of King Richard II, was unearthed in a shed in Queensland, Australia in the 1970s.

Known as an equal hour horary quadrant, it allowed its user to tell the approximate time of day based on the position of the Sun and the time of year.

The brass contraption – the second oldest dated British scientific instrument – is thought to have been discovered in the mid-1800s by an ancestor of its current owner.

It was passed down through his family who eventually emigrated to New Zealand and Australia, and was later uncovered by Christopher Becker in the mid-1970s, lurking in an old bag of pipe fittings in a shed on the family farm.

The trinket lived as a paperweight on his desk for decades until he took the decision to sell it at the Bonham's Fine Clocks and Scientific Instrument Sale on December 13.

Mr Becker said: "I believe something of this significance deserves a little more recognition than just sitting on my desk as a personal reminder of what began a lifelong passion for collecting antiques."

The quadrant, which dates back to 1396, is the oldest of a group of similar instruments dated 1398, 1399 and 1400 and is only predated by the Chaucer astrolabe, a time-telling device from 1326 which can be viewed in the British Museum.

On one face is a scale of the days of the month sitting above 12 concentric arcs – one for each month of the year – on which a table of noon solar altitudes is marked.

Above this are two rings marking out years and leap years, and within that lies a figure of a stag with a coronet around its throat – an emblem linked to Richard II.

To tell the time the user would find the noon solar altitude on the table before turning it over and stretching a string against the corresponding mark on a degree scale.

Read more at The Telegraph

First Known Europeans Identified

Europe's earliest known modern humans existed around 45,000 years ago in a southern Italian prehistoric cave, according to new research.

The discovery means that members of our own species have been present in Europe longer than previously thought, sharing turf with Neanderthals for at least 5,000 years.

"During this time it is very likely that some contact must have been achieved, but there is no direct evidence for it," Stefano Benazzi, a physical anthropologist at the University of Vienna, told Discovery News.

He explained that "Neanderthals must have survived until about 40,000 years ago."

Before the findings of Benazzi and his team, the first known modern humans in Europe came from Romania and dated to 40,000 years ago. Early Upper Paleolithic modern human cultures are documented in the Near East to about 45,000 years ago, which previously left a gap of 5,000 years between these Homo sapiens and the ones from Romania.

"With our findings, the gap is filled," said Benazzi, whose research was published this week in the journal Nature.

Benazzi and his colleagues analyzed two teeth unearthed in 1964 at Grotta del Cavallo, a prehistoric cave in what is now Puglia. During the 1960's, the teeth were identified as coming from Neanderthals.

Benazzi and his team, however, used the latest technology, including digital models from CT scans, to examine the teeth and compare them to others belonging to Neanderthals and our species. They found that the internal and external features of the teeth better match those of modern humans.

Strengthening the determination is yet another Nature paper by a different team. That study reexamined another fossil -- in this case a jaw -- once attributed to a Neanderthal.

The new analysis determined the jaw belonged to an early modern human who lived between 44,200-41,500 years ago in what is now close to Torquay, United Kingdom.

The teeth belonged to members of what is called the Uluzzian culture. These individuals were known for fairly sophisticated bone tools, shell beads and mineral colorants that indicate these people were interested in symbolic behavior, such as wearing jewelry and sporting tattoos.

Many papers have attributed such behavior to Neanderthals in the region, but now that's in question.

Benazzi said the new findings do not provide any evidence of how the people first came to Europe, "but it is most likely that the first settlers arrived from the east, maybe along the Danube corridor."

He added, "An inherent problem in studying Pleistocene populations (prior to the Holocene or the last 10,000 years) is that the landscape has changed dramatically and large regions of the continent are now submerged. Seafaring across the Mediterranean could be a possibility, but again we have no evidence for this at the moment."

Thomas Higham of the University of Oxford, who co-authored the other Nature paper, said the new studies tell "us a great deal about how rapidly our species dispersed across Europe during the last Ice Age."

He said the discoveries also mean "that early humans must have co-existed with Neanderthals in this part of the world, something which a number of researchers have doubted."

Gerhard Weber, deputy head of the University of Vienna's Department of Anthropology, points out the studies were "made possible through technical innovations developed in the last decade."

Read more at Discovery News

Legendary Viking Sunstone Navigation: Solved

Mythical crystals and a “sixth sense?” Really? But a group of physicists and optometrists say they have cracked the optical properties of the Viking sunstone, which legend has it aided the northerly, often storm-beset navigators long before the invention of the compass. But to do it requires using a squid-like sense of direction.

A report released today in the Proceedings of the Royal Society A lays out the possible inner workings of the Vikings’ legendary sólarsteinn, which was said to reveal the true bearing of a hidden sun, even on overcast days and during long summer twilights in the northerly latitudes. Researchers long speculated that the sunstone might have been a transparent type of calcite, common in Iceland, that has optical properties akin to linearly polarizing filters for a camera (see photograph above).

Light passing through such a crystal, including the common Iceland spar, changes in brightness and color as the crystal is rotated. Vikings presumably could have used such crystals to observe polarization patterns and thereby pinpoint the direction of the sun. But exactly how this was done was an enigma, until now. Guy Ropars and Albert Le Floch of the University of Rennes' Laser Physics Laboratory in France, led the latest study, which has solved the mystery of the myth they say by attacking the problem backwards.

“Rather than thinking in term of polarizer, we have deliberately chosen to ‘destroy’ the polarization of the light,” Ropars told Discovery News. “Iceland spar behaves theoretically and experimentally like a perfect depolarizer.” In other words, with the crystal held up to the sky, there is one specific angle of rotation, called the isotropy point, at which the crystal eliminates all polarization of the light passing through it.

Here’s where the “sixth sense” comes in: The investigators say that if you look through the crystal in its depolarizing position and then pull it away suddenly from your line of sight, you can catch a glimpse of a faint, elongate yellowish pattern known as a Haidinger’s Brush. The key here is that the ends of that yellow shape point directly toward the sun.

The Haidinger’s Brush phenomenon amounts to a greatly scaled-down version of the specialized ability of many insects, cephalopods, amphibians and other animals to “see” polarization patterns in the sky or water. That’s how those animals navigate. Turns out the Vikings may have too. When Ropars’ group asked test subjects to use their method to identify sun direction, their answers were accurate within 5 degrees.

Coupled with a second technique observing the changing polarization patterns passing through the crystal, also tested and described for the first time in this study, the Vikings could have established a reference point that could be used even when the sun was fully hidden, upping the sunstone’s accuracy to within 1 degree.

Ropars insists that sunstones could have helped the Vikings in their navigation from Norway to America, as the magnetic compass had yet to be introduced in Europe. Alas, archaeologists are quick to point out that no Iceland spar has yet been found in a Viking village.

Read more at Discovery News

Face discovered in testicular tumour

When "faces" are discovered in unexpected locations they are often hailed as miracles, for example the mysterious appearance of Jesus in a frying pan or - even more improbably - on a toilet door in Glasgow.

But rather than attempting to load their find with religious significance the urologists who discovered it followed good scientific practise and sent it away to be peer reviewed.

The image of the man's face, seemingly in some distress, was sent to Urology, the International Society of Urology's official journal, and was published in the journal's September volume.

G. Gregory Roberts and Naji J. Touma, from Queen's University in Ontario, Canada, had conducted the ultrasound to examine an unusual mass in the testicle of a 45-year-old patient.

Writing in the journal, they said: "The residents and staff alike were amazed to see the outline of a man’s face staring up out of the image, his mouth agape as if the face seen on the ultrasound scan itself was also experiencing severe epididymo-orchitis,” wrote the authors, referring to an inflammatory condition.

“A brief debate ensued on whether the image could have been a sign from a deity (perhaps ‘Min,’ the Egyptian god of male virility); however, the consensus deemed it a mere coincidental occurrence rather than a divine proclamation.”

The testicle was removed and the mass was discovered to be harmless.

Taken from The Telegraph

Fibonacci: the man who figured out flowers

Try to imagine a day without numbers. Try to imagine getting through the first hour of that day. No alarm clock, no time, no date, no television or radio, no stock market report or sports results in the newspapers, no bank account to check.

The fact is, our lives depend on numbers. You may not have "a head for figures", but you certainly have a head full of them. Most of what we do each day is conditioned by numbers. Indeed, the degree to which our modern society depends on those that are hidden from us was made clear by the financial meltdown in 2008, when overconfident reliance on the advanced mathematics of the credit market led to a collapse of the global financial system.

How did we become so familiar with, and so reliant on, these abstractions that our ancestors invented just a few thousand years ago? By the latter part of the first millennium AD, the system we use today to write numbers and do arithmetic had been worked out – expressing any number using just the 10 numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and adding, subtracting, multiplying, and dividing them by the procedures we are all taught in primary school. This familiar way to write numbers and do arithmetic is known as the Hindu-Arabic system, a name that reflects its history.

Before the 13th century, however, the only Europeans aware of this system were, by and large, scholars, who used it solely to do mathematics. Traders recorded their data using Roman numerals, and performed calculations either by using their fingers or with a mechanical abacus.

That state of affairs started to change soon after 1202, the year a young Italian man, Leonardo of Pisa, whom a historian centuries later would dub "Fibonacci", completed the first general-purpose book of arithmetic in the West. Liber abbaci explained the "new" methods in terms understandable to ordinary people – and its influence did as much as any other book to shape the development of modern Western Europe.

Leonardo had learnt about the Hindu-Arabic number system when his father took him to the north African port of Bugia (now Bejaïa, in Algeria) in around 1185. Years later, his book would provide not only a bridge that allowed arithmetic to cross the Mediterranean, but also one between the mathematical cultures of the Arabic and European worlds. It was an act every bit as revolutionary as the one carried out by personal computer pioneers in the Eighties who took computing from a small group of "computer types" and made it available to, and usable by, anyone. Not only did the appearance of Liber abbaci prepare the stage for the development of modern algebra and hence modern mathematics, but it also marked the beginning of the modern financial system and the way of doing business that depends on sophisticated banking methods.

Until recently, history had relegated Leonardo to a footnote. Indeed, his name is known today primarily in connection with the Fibonacci numbers, a sequence that arises from the solution to the "rabbit problem", one of many whimsical challenges he put in Liber abbaci to break the tedium of the hundreds of practical problems that dominate the book.

Nestled between puzzles involving the division of food and money, the rabbit problem involves an attempt to count a growing population. Leonardo did not invent it: it dates back at least to the Indian mathematicians who developed the number system that Liber abbaci described. But he realised, as they did, that it was an excellent way to practise how to use the new number system.

In what was to become his most famous passage, Leonardo wrote his way into 20th-century popular culture with these words: "A certain man had one pair of rabbits together in a certain enclosed place, and one wishes to know how many are created from the pair in one year when it is the nature of them in a single month to bear another pair, and in the second month those born to bear also.'' Leonardo wanted the reader to assume that once two rabbits become fertile, they produce off-spring every month. As usual, he explained the solution in full detail, but the modern reader can rapidly discern the solution by glancing at the table Leonardo also presented, giving the rabbit population each month: one animal at the beginning, then two, then three, then five, then eight, then 13, then 21, then 34, then 55, then 89, then 144.

The general rule is that each successive number is the result of adding together the previous two: 1 + 2 = 3, 2 + 3 = 5, 3 + 5 = 8, etc. The numbers generated by this process are known today as the Fibonacci numbers, and were given their name by the French mathematician Edouard Lucas in the 1870s, after his compatriot, the historian Guillaume Libri, gave Leonardo the nickname Fibonacci in 1838.

One main reason why these numbers retain their fascination today is due to the surprising frequency with which they arise in nature. For example, the number of petals on flowers is a Fibonacci number more often than would be expected from pure chance: an iris has three petals; primroses, buttercups, wild roses, larkspur, and columbine have five; delphiniums have eight; ragwort, corn marigold, and cineria 13; asters, black-eyed Susan, and chicory 21; daisies 13, 21, or 34; and Michaelmas daisies 55 or 89. Sunflower heads, and the bases of pine cones exhibit spirals going in opposite directions: the sunflower has 21, 34, 55, 89, or 144 clockwise, paired respectively with 34, 55, 89, 144, or 233 counterclockwise; a pine cone has eight clockwise spirals and 13 counterclockwise. All Fibonacci numbers.

Read more at The Telegraph

How the koala got its voice

Koalas are cute. That much is obvious. Though marsupials and not bears, their soft fur, stubby limbs and big fluffy ears make them appear as though the rigours of evolution have spent millions of years contriving to engineer the perfect teddy. The way they hold tightly to branches looks more like cuddling than climbing.

Yet when they open their mouth, it is a different matter. Koalas are loud. They bellow a loud belch-like call that seems disproportionately powerful and deep for their meagre stature. Males use these calls to boast of their sexual prowess and to try to seduce females into choosing them as a mate. It turns out that the male koala is the Barry White of the Australian outback. Though they seem docile and can sleep for up to 19 hours a day, spring has arrived Down Under and with the mating season now under way the male’s annual concert has begun again.

Why might koalas need to make such a racket? What would drive the evolution of such an unusual talent? It could be that their snort-like songs are some form of exaggeration used when competing with rival males. Rivals hearing the deep calls might think that they were about to face a giant and, in avoiding confrontation, never find out how diminutive the singer is. This advantage could, over time, favour deeper and deeper calls as each male attempted to outdo its competitors in bragging ability.

What started off as a lie eventually became an honest advertisement of the koala’s size and condition. If every male has a deep voice, then the one with the deepest is still the best. Larger males appear to have lower voices and to be able to holler for longer, so the females are probably able to gauge which males are bigger and, to them, more attractive, by the bellows alone. The tactic seems to work: the longer, louder and more guttural the song, the more groupies the baritone koala can acquire. It may explain why the males are much larger than females.

The volume could also be related to the need to be heard over a distance. Until recently it was assumed that only one prevailing alpha male had the opportunity for breeding. Research now suggests that the calls may be alluring enough to entice females out of their home range and on to the territory of other males. This could be a mechanism to avoid inbreeding and ensures that the genes of any one male do not come to dominate the population completely.

How they make these low resonating cries had been a mystery, until a recent study published in the Journal of Experimental Biology uncovered the strange workings of their vocal apparatus. It is down to their larynx, which, surprisingly, works in a manner very similar to the human voice box. The larynx is a remarkable organ involved in breathing, sound production and protecting the windpipe from filling with food. It houses the vocal cords, which are used to modulate the pitch and volume of the voice. The vocal tracts of animals, like the pipes of a musical instrument, have frequencies at which the movement of air inside naturally vibrates and amplifies sound. The longer the pipe, the lower and louder it resonates. So when it comes to making sound, size is everything – and this is why, in general, larger animals are louder animals.

But there is a way of making the vocal tract longer even in smaller animals. Like us, the koala has what is known as a descended larynx. Its position is lower in the body and it has a muscle connecting it to the sternum, which allows it to be pulled down deeper into the chest, creating a longer vocal tract: think of it like being able to alter the pitch of a trombone by moving the telescopic slider to make the instrument longer or shorter. The result is that, although the koala is barely the size of a large house cat, it sounds as big as a lion.

It had long been thought that we humans were the only animals to possess this vocal set-up, which we use for the complex machinations involved in producing speech. Then, about 10 years ago, scientists started to uncover similar sound-producing arrangements in red and fallow deer. This proved that these traits have evolved independently on several occasions.

Read more at The Telegraph

Genes of Extinct Ancestor Survive in Modern Humans

Genes inherited from long-extinct human ancestors may be more common than thought, suggesting a Homo sapiens origin story with more than a few evolutionary one-night stands.

The latest findings involve genes from Denisovans, a recently-discovered member of the Homo genus who lived in central and eastern Asia until 40,000 years ago. Denisovans, humans and neanderthals last shared a common ancestor about 1 million years ago.

Earlier research found lingering Denisovan traces in genomes of people from Oceania. Now they’ve been found in southeast Asia, too.

“We haven’t been a very exclusive species, with a very narrow origin,” said Martin Jacobsson. Interbreeding with other members of the human family tree “is not a unique event. It’s a more complex story than we thought before.”

In a study published Oct. 31 in the Proceedings of the National Academy of Sciences, Jacobsson and co-author Pontus Skoglund searched through 1,500 human genome scans from around the world for genes found in Denisovans but not chimpanzees or Neanderthals.

While the previous finding of Denisovan inheritance involved analysis of ultra-high-resolution human genome scans, of which only a few exist, Jacobsson used low-resolution scans. These are more commonly available and allowed the researchers to detect Denisovan signals in genomes from mainland southeast Asia. A signal also appeared in South America, but Jacobsson said that’s probably a false positive.

Beyond the fun of knowing that Denisovan genomes live on, the findings add to a growing sense of the richness of the human evolutionary story.

Until relatively recently, it was thought that human ancestors trekked out of Africa about 100,000 years ago in a single straight shot, descending without diversion into modernity. But what’s emerged from fossil findings in recent years is a picture of Homo sapiens and its near relatives flowing out of Africa again and again, with some populations vanishing and others surviving, often living side-by-side.

Now, thanks to well-preserved ancient genomes, it’s possible to look at mixing: Evidence of interbreeding with Neanderthals in northern Europe was found, followed by the Denisovan studies. Critically, the new findings fit a genetic pattern suggesting multiple episodes of interbreeding with Denisovans.

“We were evolving for a little while, then isolated, then mixed again,” said Jacobsson. “It’s not so simple that you can say, there’s only been one admixture.”

“I find it really cool that people use the archaic genomes we produced to try to arrive at new insights,” said geneticist Svante Paabo of Germany’s Max Planck Institute, who originally sequenced the Denisovan genome from 40,000-year-old fingerbones found in a Siberian cave. “Of course one will have to see which of them hold up.”

As for what Denisovan genes do for people who have them, it’s hard to say. Unlike Neanderthal genes, which seem to have given human immune systems a boost, Denisovan gene function isn’t yet understood.

“It might take a little longer, until we get better-quality ancient genomes,” said Jacobsson. “But I’m guessing there are people out there trying to do this now.”

Read more at Wired Science

Sally Morgan rejects Halloween challenge to prove her psychic powers

Sally Morgan, the TV clairvoyant who styles herself as "Britain's best-loved psychic", has turned down an invitation to prove her supernatural powers on Monday.

Morgan, who claims to converse with the spirit world in sellout shows across the country, was asked to demonstrate her abilities in a Halloween challenge laid down by sceptics in Liverpool.

Morgan's lawyers, Atkins Thomson, emailed the science writer Simon Singh, who organised the scientific test of her powers, to make clear that she would not take up the challenge.

The email, from Graham Atkins, requests that Singh does not contact Morgan or her office again, and states: "You well know that we all have far more important things to do than take part in this or any other 'test' at this point. She will not attend at Liverpool or at any other time."

The email was marked "strictly private and confidential – not for publication", but after seeking independent legal advice, Singh posted the correspondence with a response on his blog.

Sceptic groups planned the test after Morgan's live show in Dublin last month at which some members of the audience reported hearing someone apparently feeding Morgan information on stage.

Morgan, who claims to have seen her first ghost at the age of four, has strongly denied any fakery and said the voices were theatre technicians chatting. The theatre supported this account in a separate statement.

Had Morgan accepted the challenge, she would have been shown pictures of 10 dead women and asked to match them to a list of their first names. The offer to take the test remains open and Morgan has been invited to discuss changes to the challenge with the group.

The US paranormal investigator James Randi backed the experiment, which qualified as a first step towards a million-dollar prize established by the James Randi Educational Foundation for any psychic who can prove their special "gift" to be real.

Read more at The Guardian

Livor Mortis: The Science of Death

You may find company among zombies and the living dead this Halloween, but the science of the real dead might be just as bloodcurdling.

Pathologists and medical examiners piece together how and when a person likely died. Fleshing out these details clue investigation teams into whether a person succumbed to natural causes, an accident or by the actions of someone else. But to make accurate estimates of time of death, they need to understand the science behind body reactions once the heart stops beating.

Though there are many factors to consider, livor mortis, a phenomenon involving the shift of blood in the body, is often examined alongside other types of clues such as rigor mortis, or muscle stiffness.

Every second, a living person's heart pumps oxygen-rich blood through the entire body in an extensive network of veins, arteries and capillaries. Blood gives organs and muscles the nutrients and warmth they need to work properly.

But what happens when the heart stops pushing blood throughout the body, and why does it matter to scientists?

For starters, the blood stops moving and gravity takes hold. If a person dies and falls on his back, blood will settle in the areas closest to the ground and will slowly drain from the body's front side. Indeed, such movement gives the dead the pale appearance we associate with a lack of life. Blood doesn't disappear, it simply moves to the backside of the body closest to the ground.

As death settles in, the blood begins to congeal, making the back of the person's body purple and pink from the influx of blood. After eight to 12 hours, the blood will usually stay that way.

But the parts of the body in direct contact with objects or the floor will appear pale because of the pressure placed on the skin's capillaries. One medical examiner and pathologist at a lecture on forensics and murder explains that when you press and hold your fingertip on the top of your hand for a few seconds, you'll release it to find it's paler than your surrounding skin. Then, it quickly turns back to your normal skin color. This is because your body recirculates the blood you temporarily pushed away.

The same concept applies when livor mortis sets in, except there's no heartbeat to push blood back into parts of the body.

Forensic scientists find livor mortis somewhat useful in helping determine when a person died. By gently pressing on areas of the deceased's skin that show livor mortis, pathologists and examiners can try to estimate when a person died.

If the area turns pale and then becomes colored again, that means the blood has not fully congealed yet and the person may have passed within the last 12 hours or so. If the area remains the same darker color, it suggests the victim may have been dead for longer than 12 hours.

Read more at Discovery News

Smart Chimp Gets Speech Like a Human

A 25-year-old chimpanzee named "Panzee" has just demonstrated that speech perception is not a uniquely human trait.

Well-educated Panzee understands more than 130 English language words and even recognizes words in sine-wave form, a type of synthetic speech that reduces language to three whistle-like tones. This shows that she isn't just responding to a particular person's voice or emotions, but instead she is processing and perceiving speech as humans do.

"The results suggest that the common ancestor of chimpanzees and humans may have had the capability to perceive speech-like sounds before the evolution of speech, and that early humans were taking advantage of this latent ability when speech did eventually emerge," said Lisa Heimbauer who presented a talk today on the chimp at the 162nd Meeting of the Acoustical Society of America in San Diego.

Heimbauer, a doctoral candidate and researcher at Georgia State University's Language Research Center, and colleagues Michael Owren and Michael Beran tested Panzee on her ability to understand words communicated via sine-wave speech, which replicates the estimated frequency and amplitude patterns of natural utterances. "Tickle," "M&M," "lemonade," and "sparkler" were just a few of the test words.

Even when the words were stripped of the acoustic constituents of natural speech, Panzee knew what they meant, correctly matching them to corresponding photos.

The findings refute what is known as the "Speech is Special" theory.

"This argument proposes that besides humans being the only species able to produce speech, due to their anatomy, they also have a specialized cognitive module to process speech," Heimbauer explained.

Supporters of the "Speech is Special" view have pointed to the fact that humans can understand speech, even when it is incomplete or highly distorted. The alternative view to the hypothesis, she said, is that auditory processing is fundamentally similar across most mammals, and that many animals have latent abilities for speech perception.

"What we are saying is that humans do not need unique cognitive abilities to process speech, and that instead, the general auditory processes that we share with apes, and probably a common ancestor, can be used to accomplish speech perception tasks," she said. "Panzee then is able to understand speech because of her early experience in a speech-rich environment, and because she was taught about the association between words and their meaning from a very early age."

"These are the same things that allow humans to learn how to understand speech," she said.

There is evidence that non-human primates use specific vocalizations in certain situations, but researchers hesitate in labeling these as being part of a "language." The communications are not believed to be very complex.

Nonetheless, the findings suggest that, with education and experience, chimpanzees can become proficient in aspects of human languages, allowing them to communicate certain feelings and desires with us.

Panzee "certainly does communicate about her wants and needs, sometimes putting two to three words together," Heimbauer said, adding that the female chimp does this using the visuo-graphic symbols that she learned when she was young.

Tecumseh Fitch, a professor in the Department of Cognitive Biology at the University of Vienna, said the research, "provides important evidence that human speech perception abilities are built upon a pre-existing auditory basis, shared with other animals," he said.

Read more at Discovery News

How Cannabis Causes 'Cognitive Chaos' in the Brain

Cannabis use is associated with disturbances in concentration and memory. New research by neuroscientists at the University of Bristol, published in the Journal of Neuroscience, has found that brain activity becomes uncoordinated and inaccurate during these altered states of mind, leading to neurophysiological and behavioural impairments reminiscent of those seen in schizophrenia.

The collaborative study, led by Dr Matt Jones from the University's School of Physiology and Pharmacology, tested whether the detrimental effects of cannabis on memory and cognition could be the result of 'disorchestrated' brain networks.

Brain activity can be compared to performance of a philharmonic orchestra in which string, brass, woodwind and percussion sections are coupled together in rhythms dictated by the conductor. Similarly, specific structures in the brain tune in to one another at defined frequencies: their rhythmic activity gives rise to brain waves, and the tuning of these brain waves normally allows processing of information used to guide our behaviour.

Using state-of-the-art technology, the researchers measured electrical activity from hundreds of neurons in rats that were given a drug that mimics the psychoactive ingredient of marijuana. While the effects of the drug on individual brain regions were subtle, the drug completely disrupted co-ordinated brain waves across the hippocampus and prefrontal cortex, as though two sections of the orchestra were playing out of synch. Both these brain structures are essential for memory and decision-making and heavily implicated in the pathology of schizophrenia.

The results from the study show that as a consequence of this decoupling of hippocampus and prefrontal cortex, the rats became unable to make accurate decisions when navigating around a maze.

Dr Jones, lead author and MRC Senior Non-clinical Fellow at the University, said: "Marijuana abuse is common among sufferers of schizophrenia and recent studies have shown that the psychoactive ingredient of marijuana can induce some symptoms of schizophrenia in healthy volunteers. These findings are therefore important for our understanding of psychiatric diseases, which may arise as a consequence of 'disorchestrated brains' and could be treated by re-tuning brain activity."

Michal Kucewicz, first author on the study, added: "These results are an important step forward in our understanding of how rhythmic activity in the brain underlies thought processes in health and disease."

Read more at Science Daily

Joking, Pretending With Toddlers Gives Them Head Start in Life Skills

Parents who joke and pretend with their toddlers are giving their children a head start in terms of life skills. Most parents are naturals at playing the fool with their kids, says a new research project funded by the Economic and Social Research Council (ESRC). However parents who feel they may need a little help in doing this can learn to develop these life skills with their tots.

"Parents, carers and early years educators shouldn't underestimate the importance of interacting with young children through jokes and pretending," researcher Dr Elena Hoicka points out. "Spending time doing this fun stuff with kids helps them learn how to do it themselves and gives them a set of skills which are important in childhood and beyond."

The latest research findings on joking and pretending with children will be highlighted at a half-day event organised as part of the ESRC's Festival of Social Science 2011. One key aim of the event will be to boost parents' confidence in joking and pretending with their toddlers through a range of hands-on activities.

Dr Hoicka's study has examined how the two very similar concepts of joking and pretending develop in children aged between 15 and 24 months. Explaining the difference between joking and pretending, Dr Hoicka says: "Both involve intentionally doing or saying the wrong thing. However, joking is about doing something wrong just for the sake of it. In contrast, pretending is about doing something wrong which is imagined to be right. For example, parents might use a sponge like a duck while pretending but use a cat as a duck when joking."

The study examined whether parents offer different cues such as tone or pitch of voice in order to help their toddlers understand and differentiate between joking and pretending. Findings reveal that parents rely on a range of language styles, sound and non-verbal cues. For example, when pretending, parents often talk slowly and loudly and repeat their actions. Conversely, parents tend to cue their children to jokes by showing their disbelief through language, and using a more excited tone of voice.

"We found that most parents employ these different cues quite naturally to help their toddlers understand and differentiate these concepts," Dr Hoicka points out. "While not all parents feel confident in their natural abilities, the research does show that making the effort to interact in this way with toddlers is important. Knowing how to joke is great for making friends, dealing with stress, thinking creatively and learning to 'think outside the box'. Pretending helps children learn about the world, interact with others, be creative and solve problems."

Read more at Science Daily