Archive for March, 2009

Ballet postures have become more extreme over time

By Ed Yong | March 31, 2009 8:30 am

Blogging on Peer-Reviewed ResearchClassical ballet is one of the more conservative of art forms. Dancers express emotion and character through the same vocabulary of postures that was originally set in 1760, and often with entire choreographies that have been handed down for centuries.

But even amid this rigorous cascade of tradition, there is room for change. Over the years, successive generations of ballet dancers have subtly tinkered with positions that are ostensibly fixed and limited by the physical constraints of a dancer’s body. The only changes ought to be a result of the dancers’ varying abilities. But that’s not the case – over the last 60 years, the position of a dancer’s has become increasingly vertical, with the moving leg in particular being lifted ever higher.

Elena Daprati from the University of Rome thinks that these tweaks have been driven by social pressures from audiences. When she reduced pictures of dancers to stick-figure drawings, she found that even people who have never seen a ballet prefer the postures of modern dancers to those of dancers 60 years ago. The results suggest that art can change very gradually because of constant interactions between performers and their audiences.

Almost more importantly, they show that the usually unquantifiable world of artistic expression can be studied with a scientific lens. In this case, the formal nature of classical ballet gave Daprati a rare opportunity to do so. Body postures could be objectively analysed, movements are standardised enough to allow for easy comparisons, and most of all, performances have been carefully archived for decades. That provided Daprati’s group with more than enough raw material for studying the evolution of ballet postures over time.

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Deformed skull of prehistoric child suggests that early humans cared for disabled children

By Ed Yong | March 30, 2009 5:00 pm

Blogging on Peer-Reviewed ResearchFor all appearances, this looks like the skull of any human child. But there are two very special things about it. The first is that its owner was clearly deformed; its asymmetrical skull is a sign of a medical condition called craniosynostosis that’s associated with mental retardation. The second is that the skull is about half a million years old. It belonged to a child who lived in the Middle Pleistocene period.

The skull was uncovered in Atapuerca, Spain by Ana Gracia, who has named it Cranium 14. It’s a small specimen but it contains enough evidence to suggest that the deformity was present from birth and that the child was about 5-8 years old. The remains of 28 other humans have been recovered from the same site and none of them had any signs of deformity.

These facts strongly suggest that prehistoric humans cared for children with physical and mental deformities that would almost have certainly prevented them from caring for themselves. Without such assistance, it’s unlikely that the child would have survived that long.

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Autistic children are less sensitive to the movements of living things

By Ed Yong | March 30, 2009 8:00 am

Blogging on Peer-Reviewed ResearchFor any animal, it pays to be able to spot other animals in order to find mates and companions and to avoid predators. Fortunately, many animals move in a distinct way, combining great flexibility with the constraints of a rigid skeleton – that sets them apart from inanimate objects like speeding trains or flying balls. The ability to detect this “biological motion” is incredibly important. Chicks have it. Cats have it. Even two-day-old babies have it. But autistic children do not.

Ami Klim from Yale has found that two-year-old children with autism lack normal preferences for natural movements. This difference could explain many of the problems that they face in interacting with other people because the ability to perceive biological motion – from gestures to facial expressions – is very important for our social lives.

Indeed, the parts of the brain involved in spotting them overlap with those that are involved in understanding the expressions on people’s faces or noticing where they are looking. Even the sounds of human motion can activate parts of the brain that usually only fire in response to sights.

You can appreciate the importance of this “biological motion” by looking at “point-light” animations, where a few points of light placed at key joints can simulate a moving animal. Just fifteen dots can simulate a human walker. They can even depict someone male or female, happy or sad, nervous or relaxed. Movement is the key – any single frame looks like a random collection of dots but once they move in time, the brain amazingly extracts an image from them.

But Klim found that autistic children don’t have any inclination toward point-light animations depicting natural movement. Instead, they were attracted to those where sounds and movements were synchronised – a feature that normal children tend to ignore. Again, this may explain why autistic children tend to avoid looking at people’s eyes, preferring instead to focus on their mouths.

Alim created a series of point-light animations used the type of motion-capture technology used by special effects technicians and video game designers. He filmed adults playing children’s games like “peek-a-boo” and “pat-a-cake” and converted their bodies into mere spots of light. He then showed two animations side-by-side to 76 children, of whom 21 had autism, 16 were developing slowly but were not autistic, and 39 were developing normally.

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Playing shoot-em-up video games can improve some aspects of vision

By Ed Yong | March 29, 2009 1:00 pm

Blogging on Peer-Reviewed ResearchAnyone who has played video games for too long is probably familiar with the sore, tired and dry eyes that accompany extended bouts of shooting things with rocket launchers. So it might come as a surprise that playing games could actually improve a key aspect of our eyesight.

Renjie Li from the University of Rochester found that intensive practice at shoot-em-ups like Unreal Tournament 2004 and Call of Duty 2 improved a person’s ability to spot the difference between subtly contrasting shades of grey. In the real world, this “contrast sensitivity function” is reflected in the crispness of our vision, affecting how well we see objects that don’t stand out well against their backgrounds. It’s the key to our ability to drive or walk about at night, or in conditions with poor visibility.

Unfortunately, contrast sensitivity is one of the first aspects of our vision to go with ageing and it’s compromised by conditions like lazy eyes. This loss can be caused by either faults with the eye itself or neurological problems. Opticians usually try to treat the former with glasses, contact lenses or laser surgery, but Li’s group have found that action video games can provide a counter-intuitive solution for the latter. Compared to other enjoyable but less hair-trigger games, like the Sims, playing shoot-em-ups seems to improve contrast sensitivity and their benefits last for months or even years.

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The evolution of animal personalities – they're a fact of life

By Ed Yong | March 28, 2009 12:00 pm

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Animals have distinct personalities and temperaments, but why would evolution favour these over more flexible and adaptible mindsets? New game theory models show that animal personalities are a natural progression from the choices they make over how to live and reproduce.

Any pet owner, wildlife photographer or zookeeper will tell you that animals have distinct personalities. Some are aggressive, others are docile; some are bold, others are timid.

An animal's reproductive decisions can determine if it is a hawk...In some circles, ascribing personalities to animals is still a cardinal sin of biology and warrants being branded with a scarlet A (for anthropomorphism). Nonetheless, scientists have consistently found evidence of personality traits in species as closely related to us as chimpanzees, and as distant as squid, ants and spiders.

These traits may exist, but they pose an evolutionary puzzle because consistent behaviour is not always a good thing. The consistently bold animal could well become a meal if it stands up to the wrong predator, or seriously injured if it confronts a stronger rival. The ideal animal is a flexible one that can continuously adjust its behaviour in the face of new situations.

And yet, not only do personality types exist but certain traits are related across the entire animal kingdom. Aggression and boldness toward predators are part of a general ‘risk-taking’ personality that scientists have found in fish, birds and mammals.

Max Wolf and colleagues from The University of Groningen, Netherlands, have found a way to explain this discrepancy. Using game theory models, they have shown that personalities arise because of the way animals live their lives and decide when to reproduce.

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Termite queen avoids inbreeding by leaving a legacy of clones

By Ed Yong | March 27, 2009 8:30 am

Blogging on Peer-Reviewed ResearchTermite colonies are families – millions of individual workers all descended from one king and one queen. But the colony itself tends to outlast this initial royal couple. When they die, new kings and queens rise to take their place. These secondary royals are a common feature of some families of termites, and they will often mate with each other for many generations. But there is more to this system than meets the eye.

Kenji Matsuura from Okayama University has found that the secondary queens are all genetically identical clones of the original. There are many copies, and they have no father – they developed from unfertilised eggs laid by the first queen through a process called parthenogenesis. These clones then mate with the king to produce the rest of the colony through normal sexual means.

It’s a fiendishly clever strategy. The original queen’s legacy to the colony is… herself. She effectively splits herself into several different bodies and in doing so, greatly increases the number of offspring she has. And because each of these descendants mates with the king, who has no genes in common with them, the colony neatly skirts around the problems of inbreeding.

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There's no you in Yong…

By Ed Yong | March 26, 2009 9:28 pm

Apropos of nothing, a whinge: my name has no u in it. It rhymes with “song” not “sung” and “long” but not “lung”.
I’m fairly used to people adding in the errant u but for some reason, this has been annoying me of late. Seriously, there are only four letters, six if you count the first name too. It can’t possibly be that hard.
Ed Young is another person entirely, who looks not entirely unlike a Terminator on happy pills. And while he has written more books than me, they’re, er, of a different ilk.

CATEGORIZED UNDER: Personal

What makes 250,000,000 fish gather in the same place?

By Ed Yong | March 26, 2009 2:00 pm

Blogging on Peer-Reviewed ResearchOn the 3rd of October, 2006, Nicolas Makris watched a quarter of a billion fish gather in the same place. They were Atlantic herring, one of the most abundant fishes in the ocean and one prone to gathering in massive schools. This was the first time that anyone had watched the full scope of the event, much less capture it on video.

The first signs of the amassing herring appeared around 5pm and by sunset, the gathering had begun in earnest. Once a critical level of fish was reached, the shoal expanded at a breakneck pace, suddenly growing to cover tens of kilometres within the hour. By midnight, the shoal contained about 250,000,000 individuals – 50,000 tonnes of fish gathered in one place.

The ability of fish to congregate in gigantic schools may be familiar but until now, we’ve known remarkably little about the things that set off these gatherings. Without Facebook as a coordinator, what causes small groups of herring to take sociability to an extreme? Scientists have tried to follow gathering fish aboard research vessels but these can usually only see a small fraction of the massive schools are any one time.

Makris wasn’t so hampered. He used a new technique called Ocean Acoustic Waveguide Remote Sensing (OAWRS) that can visualise fish populations over vast distances in real-time. It needs two ships, one to send out sound waves in all directions and a second to pick up their echoes as they bounce off fish and floor alike.

In an instant, it can scan an area of ocean 100km in diameter, and it can update its images every 75 seconds, providing an unprecedented view of the genesis of herring shoals. The location was Georges Bank off the coast of Maine, where herring migrate to spawn in early autumn. Makris pointed his instruments at an area where herring historically gather, and waited.

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CATEGORIZED UNDER: Animal behaviour, Fish, Fishing
MORE ABOUT: Fish, herring, school, shoal

How Kenny Rogers and Frank Sinatra could help stroke patients

By Ed Yong | March 25, 2009 8:30 am

Blogging on Peer-Reviewed ResearchWe’re used to thinking of neglect as a lack of appropriate care, but to a neuroscientist, it has a very different meaning. “Spatial neglect” is a neurological condition caused by damage to one half of the brain (usually the right), where patients find it difficult to pay attention to one half of their visual space (usually the left).

This bias can affect their mental images too. If neglect patients are asked to draw clocks, many only include the numbers from 12 to 6, while some shunt all the numbers to the right side. When two famous neglect patients were asked to describe a familiar square in Milan, the city they grew up in, the landmarks they reported shifted depending on where they pictured themselves standing in the square. They would only report buildings to the right of their imagined position – swap the location and new buildings would suddenly come into mental view.

Patients tend to be particularly unaware of things on the left if other objects on the right are vying for their attention – this phenomenon, where only one of two simultaneously presented objects is seen, is called “visual extinction“.

Neglect is clearly a fascinating condition but also a debilitating and underappreciated one. It affects up to 60% of patients who suffer strokes on the right side of their brain, and it can hamper recovery and deny patients their independence. As such, there are plenty of researchers interested in finding ways of improving its symptoms. David Soto from Imperial College London is one of them, and he has discovered a deceptively simple way of helping neglect patients to regain their lost awareness – listen to their favourite music.

Soto was encouraged by a recent study, which found that stroke victims showed greater improvements in both memory and attention when they tuned into music than when they listened to audiobooks or worked in silence. And other studies have suggested that emotional faces are less likely to fall prey to visual extinction than less compelling images. But Soto wanted to see if the patient’s own emotional state had anything to do with their awareness. Would it be possible to reduce the symptoms of neglect simply by making patients feel happier through the medium of pleasant melodies?

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Genetic neoteny – how delayed genes separate human brains from chimps

By Ed Yong | March 24, 2009 8:30 am

Blogging on Peer-Reviewed ResearchBe it in sports or comedy, they say that timing is everything. In evolution, it’s no different. Many of the innovations that have separated us from other apes may have arisen not through creating new genetic material, but by subtly shifting how the existing lot is used.

Take our brains, for example. In the brains of humans, chimps and many other mammals, the genes that are switched on in the brain change dramatically in the first few years of life. But Mehmet Somel from the Max Planck Institute for Evolutionary Anthropology has found that a small but select squad of genes, involved in the development of nerve cells, are activated much later in our brains than in those of other primates.

This genetic delay mirrors other physical shifts in timing that separate humans from other apes. Chimpanzees, for example, become sexually mature by the age of 8 or 9; we take five more years to reach the same point of development.

These delays are signs of an evolutionary process called “neoteny“, where a species’ growth slows down to the point where adults retain many of the features previously seen juveniles. You can see neoteny at work in some domestic dog breeds, which are remarkably similar to baby wolves, or the axolotl salamander, which keeps the gills of a larva even as it becomes a sexually mature adult. And some scientists, like the late Stephen Jay Gould, have suggested that neoteny has played a major role in human evolution too.

As adults, we share many of the physical features of immature chimps. Our bone structures, including flat faces and small jaws, are similar to those of juvenile chimps, as is our patchy distribution of hair. A slower rate of development may even have shaped our vaunted intelligence, by stretching out the time when we are most receptive to new skills and knowledge. Somel’s research supports this idea by showing that since our evolutionary split from chimpanzees, the activation of some important brain genes has been delayed to the very start of adolescence.

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