Cambridge 15 — Test 1 den Test 4

The nutmeg tree, Myristica fragrans, is a large evergreen tree native to Southeast Asia. Until the late 18th century, it only grew in one place in the world: a small group of islands in the Banda Sea, part of the Moluccas — or Spice Islands — in northeastern Indonesia. The tree produces small, yellow, bell-shaped flowers and pale yellow pear-shaped fruits. Inside is a purple-brown shiny seed surrounded by a lacy red covering called an ‘aril’. These are the sources of the two spices nutmeg and mace, the former being produced from the dried seed and the latter from the aril.

Nutmeg was a highly prized and costly ingredient in European cuisine in the Middle Ages, and was used as a flavouring, medicinal, and preservative agent. Throughout this period, the Arabs were the exclusive importers of the spice to Europe. They sold nutmeg for high prices to merchants based in Venice, but they never revealed the exact location of the source of this extremely valuable commodity. The Arab-Venetian dominance of the trade finally ended in 1512, when the Portuguese reached the Banda Islands.

Always in danger of competition from neighbouring Spain, the Portuguese began subcontracting their spice distribution to Dutch traders. Profits began to flow into the Netherlands, and the Dutch commercial fleet swiftly grew. Then, in 1580, Portugal fell under Spanish rule, and by the end of the 16th century the Dutch found themselves locked out of the market. As prices for pepper, nutmeg, and other spices soared across Europe, they decided to fight back.

In 1602, Dutch merchants founded the VOC, a trading corporation better known as the Dutch East India Company. By 1617, the VOC was the richest commercial operation in the world, with 50,000 employees worldwide, a private army of 30,000 men and a fleet of 200 ships. At the same time, thousands of people across Europe were dying of the plague, and doctors decided nutmeg held the cure. Nutmeg bought for a few pennies in Indonesia could be sold for 68,000 times its original cost on the streets of London.

The Banda Islands were ruled by local sultans who insisted on maintaining a neutral trading policy towards foreign powers. In 1621, the Dutch arrived and took over. They concentrated all nutmeg production into a few easily guarded areas, uprooting and destroying any trees outside the plantation zones. Anyone caught growing a nutmeg seedling or carrying seeds without authority was severely punished. All exported nutmeg was covered with lime to prevent fertile seeds from leaving the islands. There was only one obstacle to Dutch domination: a sliver of land called Run, only 3 km long by less than 1 km wide, under British control.

After decades of fighting, the Dutch and British arrived at a compromise settlement, the Treaty of Breda, in 1667. The Dutch offered a trade: if the British would give them the island of Run, they would in turn give Britain a distant and much less valuable island in North America. The British agreed. That other island was Manhattan, which is how New Amsterdam became New York. The Dutch now had a monopoly over the nutmeg trade which would last for another century.

Then, in 1770, a Frenchman named Pierre Poivre successfully smuggled nutmeg plants to Mauritius, an island off the coast of Africa. Some of these were later exported to the Caribbean where they thrived, especially on the island of Grenada. In 1778, a volcanic eruption in the Banda region caused a tsunami that wiped out half the nutmeg groves. Finally, in 1809, the British seized the Banda Islands by force, and before returning them to the Dutch in 1817, transplanted hundreds of nutmeg seedlings to plantations across southern Asia. The Dutch nutmeg monopoly was over. Today, nutmeg is grown in Indonesia, the Caribbean, India, Malaysia, Papua New Guinea and Sri Lanka.

A. The automotive sector is well used to adapting to automation in manufacturing. A new challenge to vehicle production is now on the horizon: this time it is not to do with the manufacturing process, but with the vehicles themselves. Research projects on vehicle automation are not new — vehicles with limited self-driving capabilities have been around for more than 50 years. But since Google announced in 2010 that it had been trialling self-driving cars on the streets of California, progress in this field has quickly gathered pace.

B. There are many reasons why technology is advancing so fast. One frequently cited motive is safety; research at the UK's Transport Research Laboratory has demonstrated that more than 90 percent of road collisions involve human error as a contributory factor. Automation may help to reduce the incidence of this. Another aim is to free the time people spend driving for other purposes — being productive, socialising or simply relaxing. If the vehicle can do the driving, those who are challenged by existing mobility models — such as older or disabled travellers — may be able to enjoy significantly greater travel autonomy.

C. Beyond these direct benefits, we can consider the wider implications for transport and society. At present, the average car spends more than 90 percent of its life parked. Automation means that initiatives for car-sharing become much more viable, particularly in urban areas with significant travel demand. If a significant proportion of the population choose to use shared automated vehicles, mobility demand can be met by far fewer vehicles.

D. The Massachusetts Institute of Technology investigated automated mobility in Singapore, finding that fewer than 30 percent of the vehicles currently used would be required if fully automated car sharing could be implemented. Modelling work by the University of Michigan Transportation Research Institute suggests automated vehicles might reduce vehicle ownership by 43 percent, but that vehicles' average annual mileage would double as a result. Each vehicle would be used more intensively, and might need replacing sooner. This faster rate of turnover may mean that vehicle production will not necessarily decrease.

E. Automation may prompt other changes in vehicle manufacture. If consumers are tending not to own a single vehicle but to purchase access to a range of vehicles through a mobility provider, drivers will have the freedom to select one that best suits their needs for a particular journey. Since for most of the time most of the seats in most cars are unoccupied, this may boost production of a smaller, more efficient range of vehicles. Specialised vehicles may then be available for exceptional journeys, such as going on a family camping trip or helping a son or daughter move to university.

F. There are a number of hurdles to overcome in delivering automated vehicles to our roads. These include the technical difficulties in ensuring that the vehicle works reliably in the infinite range of traffic, weather and road situations it might encounter; the regulatory challenges in understanding how liability and enforcement might change when drivers are no longer essential; and the societal changes that may be required for communities to trust and accept automated vehicles as being a valuable part of the mobility landscape.

G. It's clear that there are many challenges that need to be addressed but, through robust and targeted research, these can most probably be conquered within the next 10 years. Mobility will change in such potentially significant ways and in association with so many other technological developments that it is hard to make concrete predictions about the future. However, one thing is certain: change is coming, and the need to be flexible in response to this will be vital for those involved in manufacturing the vehicles that will deliver future mobility.

We are all explorers. Our desire to discover, and then share that new-found knowledge, is part of what makes us human. Long before the first caveman slumped down beside the fire and grunted news that there were plenty of wildebeest over yonder, our ancestors had learnt the value of sending out scouts to investigate the unknown. This questing nature of ours undoubtedly helped our species spread around the globe.

Over the years, we've come to think of explorers as a peculiar breed — different from the rest of us. But that doesn't take away from the fact that we all have this enquiring instinct, even today; and that in all sorts of professions — whether artist, marine biologist or astronomer — borders of the unknown are being tested each day.

In this book about the exploration of the earth's surface, I have confined myself to those whose travels were real and who also aimed at more than personal discovery. But that still left me with another problem: the word 'explorer' has become associated with a past era. We think back to a golden age, as if exploration peaked somehow in the 19th century. But the truth is that we have named only one and a half million of this planet's species, and there may be more than 10 million. We have scarcely mapped the ocean floors, and know even less about ourselves; we fully understand the workings of only 10 percent of our brains.

Here is how some of today's 'explorers' define the word. Ran Fiennes, dubbed the 'greatest living explorer', said, "An explorer is someone who has done something that no human has done before — and also done something scientifically useful." Chris Bonington felt exploration was to be found in the act of physically touching the unknown: "You have to have gone somewhere new." Robin Hanbury-Tenison said, "A traveller simply records information about some far-off world, and reports back; but an explorer 'changes' the world." Wilfred Thesiger told me, "If I'd gone across by camel when I could have gone by car, it would have been a stunt."

Each definition is slightly different — and tends to reflect the field of endeavour of each pioneer. They each set their own particular criteria; the common factor in their approach being that they all had both a very definite objective from the outset and also a desire to record their findings.

I'd best declare my own bias. As a writer, I'm interested in the exploration of ideas. The time has long passed for the great continental voyages — another walk to the poles, another crossing of the Empty Quarter. We know how the land surface of our planet lies; exploration of it is now down to the details. However, this is to disregard the role the human mind has in conveying remote places; and this is what interests me: how a fresh interpretation, even of a well-travelled route, can give its readers new insights.

A. The way we travel around cities has a major impact on whether they are sustainable. Transportation is estimated to account for 30% of energy consumption in most developed nations, so lowering the need for energy-using vehicles is essential. Engineers are tasked with changing how we travel round cities through urban design, but the engineering industry still works on assumptions that led to the creation of the energy-consuming transport systems we have now: the emphasis placed solely on efficiency, speed, and quantitative data. We need radical changes, to make it healthier, more enjoyable, and less environmentally damaging to travel around cities.

B. Dance might hold some of the answers. That is not to suggest everyone should dance their way to work, but rather that the techniques used by choreographers to experiment with and design movement in dance could provide engineers with tools to stimulate new ideas in city-making. Richard Sennett, an influential urbanist and sociologist, argues that urban design has suffered from a separation between mind and body since the introduction of the architectural blueprint.

C. Whereas medieval builders improvised and adapted construction through their intimate knowledge of materials and personal experience of the conditions on a site, building designs are now conceived and stored in media technologies that detach the designer from the physical and social realities they are creating. While the design practices created by these new technologies are essential for managing the technical complexity of the modern city, they have the drawback of simplifying reality in the process.

D. To illustrate, Sennett discusses the Peachtree Center in Atlanta, USA, a development typical of the modernist approach to urban planning prevalent in the 1970s. According to Sennett, this failed because its designers had invested too much faith in computer-aided design to tell them how it would operate. They failed to take into account that purpose-built street cafes could not operate in the hot sun without protective awnings, and that its giant car park would feel so unwelcoming that it would put people off getting out of their cars. What seems entirely predictable and controllable on screen has unexpected results when translated into reality.

E. The same is true in transport engineering, which uses models to predict and shape the way people move through the city. The guard rails that will be familiar to anyone who has attempted to cross a British road, for example, were an engineering solution to pedestrian safety based on models that prioritise the smooth flow of traffic. On wide major roads, they often guide pedestrians to specific crossing points and slow down their progress. These barriers don't just make it harder to cross the road: they divide communities and decrease opportunities for healthy transport. As a result, many are now being removed, causing disruption, cost, and waste.

F. If their designers had had the tools to think with their bodies — like dancers — and imagine how these barriers would feel, there might have been a better solution. In order to bring about fundamental changes to the ways we use our cities, engineering will need to develop a richer understanding of why people move in certain ways, and how this movement affects them. Choreography shares with engineering the aim of designing patterns of movement within limitations of space. It is an art form developed almost entirely by trying out ideas with the body, and gaining instant feedback on how the results feel.

G. Observing the choreographer Wayne McGregor, cognitive scientist David Kirsh described how he 'thinks with the body'. Kirsh argues that by using the body to simulate outcomes, McGregor is able to imagine solutions that would not be possible using purely abstract thought. A suggested method for transport engineers is to improvise design solutions and get instant feedback about how they would work from their own experience of them, or model designs at full scale in the way choreographers experiment with groups of dancers. Above all, perhaps, they might learn to design for emotional as well as functional effects.

A. The passenger pigeon was a legendary species. Flying in vast numbers across North America, with potentially many millions within a single flock, their migration was once one of nature's great spectacles. Sadly, the passenger pigeon's existence came to an end on 1 September 1914, when the last living specimen died at Cincinnati Zoo. Geneticist Ben Novak is lead researcher on an ambitious project which now aims to bring the bird back to life through a process known as 'de-extinction'. The basic premise involves using cloning technology to turn the DNA of extinct animals into a fertilised embryo, carried by the nearest relative still in existence.

B. In Australia, the thylacine, more commonly known as the Tasmanian tiger, is another extinct creature which genetic scientists are striving to bring back to life. Michael Archer of the University of New South Wales points out that since the thylacine went extinct, a 'dangerously debilitating' facial tumour syndrome threatens the existence of the Tasmanian devils. Thylacines would have prevented this spread because they would have killed significant numbers of Tasmanian devils, and if that contagious cancer had popped up previously, it would have burned out in whatever region it started. The return of thylacines to Tasmania could help to ensure that devils are never again subjected to risks of this kind.

C. If extinct species can be brought back to life, can humanity begin to correct the damage it has caused to the natural world? "There is no way to bring back something that is 100 percent identical to a species that went extinct a long time ago," says Beth Shapiro of University of California Santa Cruz's Genomics Institute. A more practical approach for long-extinct species is to take the DNA of existing species as a template, inserting strands of extinct animal DNA to create something new; a hybrid, based on the living species, but which looks and/or acts like the animal which died out.

D. This complicated process begs the question: what is the actual point of this technology? "For us, the goal has always been replacing the extinct species with a suitable replacement," explains Novak. Since the disappearance of the passenger pigeon, ecosystems in the eastern US have suffered, as the lack of disturbance caused by thousands of passenger pigeons wrecking trees and branches means there has been minimal need for regrowth. This has left forests stagnant. According to Novak, a hybridised band-tailed pigeon with the added nesting habits of a passenger pigeon could re-establish that forest disturbance, thereby creating a habitat necessary for a great many other native species to thrive.

E. Another popular candidate for this technology is the woolly mammoth. George Church, professor at Harvard Medical School, has been focusing on cold resistance, the main way in which the extinct woolly mammoth and its nearest living relative, the Asian elephant, differ. The project's goal is to return mammoths, or a mammoth-like species, to the tundra. "My highest priority would be preserving the endangered Asian elephant," says Church, "expanding their range to the huge ecosystem of the tundra." This repopulation of the tundra with large mammals could also be a useful factor in reducing carbon emissions.

F. While the prospect of bringing extinct animals back to life might capture imaginations, it is, of course, far easier to try to save an existing species which is merely threatened with extinction. "Many of the technologies that people have in mind when they think about de-extinction can be used as a form of 'genetic rescue'," explains Shapiro. She prefers to focus the debate on how this emerging technology could be used to fully understand why various species went extinct, and how we could use it to make genetic modifications which could prevent mass extinctions in the future. "I would also say there's an incredible moral hazard to not do anything at all," she continues. "We know that what we are doing today is not enough, and we have to be willing to take some calculated and measured risks."

Humans start developing a sense of humour as early as six weeks old, when babies begin to laugh and smile in response to stimuli. Laughter is universal across all human cultures and even exists in some form in rats, chimps, and bonobos. Like other human emotions and expressions, laughter and humour provide psychological scientists with rich resources for studying human psychology, ranging from the development of language to the neuroscience of social perception.

Theories focusing on the evolution of laughter point to it as an important adaptation for social communication. Back in 1950, US sound engineer Charley Douglass hated dealing with the unpredictable laughter of live audiences, so started recording his own 'laugh tracks' intended to help people at home feel like they were in a social situation, such as a crowded theatre. Douglass even recorded various types of laughter, as well as mixtures of laughter from men, women, and children. In doing so, he picked up on a quality of laughter that is now interesting researchers: a simple 'haha' communicates a remarkable amount of socially relevant information.

In one study conducted in 2016, samples of laughter from pairs of English-speaking students were recorded at the University of California, Santa Cruz. A team made up of more than 30 psychological scientists, anthropologists, and biologists then played these recordings to listeners from 24 diverse societies, from indigenous tribes in New Guinea to city-dwellers in India and Europe. Participants were asked whether they thought the people laughing were friends or strangers. On average, the results were remarkably consistent: worldwide, people's guesses were correct approximately 60% of the time.

Researchers have also found that different types of laughter serve as codes to complex human social hierarchies. A team led by Christopher Oveis found that high-status individuals had different laughs from low-status individuals, and that strangers' judgements of an individual's social status were influenced by the dominant or submissive quality of their laughter. Analysis revealed that high-status individuals produced more dominant laughs and fewer submissive laughs. Dominant laughter was higher in pitch, louder, and more variable in tone than submissive laughter.

A random group of volunteers then listened to an equal number of dominant and submissive laughs from both the high- and low-status individuals, and were asked to estimate the social status of the laugher. Laughers producing dominant laughs were perceived to be significantly higher in status. "This was particularly true for low-status individuals, who were rated as significantly higher in status when displaying a dominant versus submissive laugh," Oveis and colleagues note. "Thus, by strategically displaying more dominant laughter when the context allows, low-status individuals may achieve higher status in the eyes of others."

Another study, conducted by David Cheng and Lu Wang of Australian National University, was based on the hypothesis that humour might provide a respite from tedious situations in the workplace. To test this theory, the researchers had students first perform a tedious task, then randomly assigned them to watch a video clip eliciting either humour, contentment, or neutral feelings: some watched the BBC comedy Mr. Bean, others a relaxing scene with dolphins, and others a factual video about the management profession.

The students then completed a task requiring persistence in which it was nearly impossible to achieve 10 consecutive correct answers. Students who had watched the Mr. Bean video ended up spending significantly more time working on the task, making twice as many predictions as the other two groups. Cheng and Wang conclude: "We suggest that humour is not only enjoyable but more importantly, energising."

Henry Moore was born in Castleford, a small town near Leeds in the north of England. He studied at Castleford Grammar School from 1909 to 1915, where his early interest in art was encouraged by his teacher Alice Gostick. After leaving school, Moore hoped to become a sculptor, but instead he complied with his father's wish that he train as a schoolteacher. He had to abandon his training in 1917 when he was sent to France to fight in the First World War.

After the war, Moore enrolled at the Leeds School of Art, where he studied for two years. At the end of that year, he passed the sculpture examination and was awarded a scholarship to the Royal College of Art in London. In September 1921, he moved to London and began three years of advanced study in sculpture.

Alongside the instruction he received at the Royal College, Moore visited many of the London museums, particularly the British Museum, which had a wide-ranging collection of ancient sculpture. During these visits, he discovered the power and beauty of ancient Egyptian and African sculpture. As he became increasingly interested in these 'primitive' forms of art, he turned away from European sculptural traditions.

After graduating, Moore spent the first six months of 1925 travelling in France. When he visited the Trocadero Museum in Paris, he was impressed by a cast of a Mayan sculpture of the rain spirit. It was a male reclining figure with its knees drawn up together, and its head at a right angle to its body. Moore became fascinated with this stone sculpture, which he thought had a power and originality that no other stone sculpture possessed. He himself started carving a variety of subjects in stone, including depictions of reclining women, mother-and-child groups, and masks.

Moore's exceptional talent soon gained recognition, and in 1926 he started work as a sculpture instructor at the Royal College. In 1931, he held an exhibition at the Leicester Galleries in London. His work was enthusiastically welcomed by fellow sculptors, but the reviews in the press were extremely negative and turned Moore into a notorious figure. There were calls for his resignation from the Royal College, and the following year, when his contract expired, he left to start a sculpture department at the Chelsea School of Art.

Throughout the 1930s, Moore did not show any inclination to please the British public. He became interested in the paintings of Pablo Picasso, whose work inspired him to distort the human body in a radical way. At times, he seemed to abandon the human figure altogether. The pages of his sketchbooks from this period show his ideas for abstract sculptures that bore little resemblance to the human form.

In 1940, during the Second World War, Moore stopped teaching and moved to a farmhouse about 20 miles north of London. A shortage of materials forced him to focus on drawing. He did numerous small sketches of Londoners, later turning these ideas into large coloured drawings in his studio. In 1942, he returned to Castleford to make a series of sketches of the miners who worked there.

In 1944, Harlow offered Moore a commission for a sculpture depicting a family. The resulting work signifies a dramatic change in Moore's style, away from the experimentation of the 1930s towards a more natural and humanistic subject matter. He did dozens of studies in clay for the sculpture, and these were cast in bronze and issued in editions of seven to nine copies each. In this way, Moore's work became available to collectors all over the world, enabling him to take on ambitious projects and start working on the scale he felt his sculpture demanded.

In his final years, Moore created the Henry Moore Foundation to promote art appreciation and to display his work. Moore was the first modern English sculptor to achieve international critical acclaim and he is still regarded as one of the most important sculptors of the 20th century.

A. Travelling around Thailand in the 1990s, William Janssen was impressed with the basic rooftop solar heating systems that were on many homes, where energy from the sun was absorbed by a plate and then used to heat water for domestic use. Two decades later Janssen developed that basic idea he saw in Southeast Asia into a portable device that uses the power from the sun to purify water.

B. The Desolenator operates as a mobile desalination unit that can take water from different places, such as the sea, rivers, boreholes and rain, and purify it for human consumption. It is particularly valuable in regions where natural groundwater reserves have been polluted, or where seawater is the only water source available. "I was confronted with the enormous carbon footprint that the Gulf nations have because of all of the desalination that they do," says Janssen.

C. The Desolenator can produce 15 litres of drinking water per day, enough to sustain a family for cooking and drinking. Its main selling point is that unlike standard desalination techniques, it doesn't require a generated power supply: just sunlight. It measures 120cm by 90cm, and is easy to transport, thanks to its two wheels. Water enters through a pipe, flows as a thin film between a sheet of double glazing and the surface of a solar panel, where it is heated by the sun. The warm water flows into a small boiler where it is converted to steam. When the steam cools, it becomes distilled water. The device has a simple filter to trap particles, and there are two tubes for liquid coming out: one for the waste and another for the distilled water.

D. A recent analysis found that at least two-thirds of the world's population lives with severe water scarcity for at least a month every year. Janssen says that by 2030 half of the world's population will be living with water stress. "It is really important that a sustainable solution is brought to the market that is able to help these people," he says. Many countries "don't have the money for desalination plants, which are very expensive to build. They don't have the money to operate them, they are very maintenance intensive, and they don't have the money to buy the diesel to run the desalination plants."

E. The device is aimed at a wide variety of users — from homeowners in the developing world who do not have a constant supply of water to people living off the grid in rural parts of the US. The first commercial versions of the Desolenator are expected to be in operation in India early next year, after field tests are carried out. In the developed world, it is aimed at niche markets where tap water is unavailable — for camping, on boats, or for the military.

F. Prices will vary according to where it is bought. In the developing world, the price will depend on what deal aid organisations can negotiate. In developed countries, it is likely to come in at $1,000 (£685) a unit. "We are a venture with a social mission. We are aware that the product we have envisioned is mainly finding application in the developing world and humanitarian sector and that this is the way we will proceed. We do realise, though, that to be a viable company there is a bottom line to keep in mind," says Janssen.

G. The company itself is based at Imperial College London, although Janssen, its chief executive, still lives in the UAE. It has raised £340,000 in funding so far. Within two years, he says, the company aims to be selling 1,000 units a month, mainly in the humanitarian field. They are expected to be sold in areas such as Australia, northern Chile, Peru, Texas and California.

People of every culture tell each other fairy tales but the same story often takes a variety of forms in different parts of the world. In the story of "Little Red Riding Hood" that European children are familiar with, a young girl on the way to see her grandmother meets a wolf and tells him where she is going. You may think you know the story — but which version? In some versions, the wolf swallows up the grandmother, while in others it locks her in a cupboard. In some stories Red Riding Hood gets the better of the wolf on her own, while in others a hunter or a woodcutter hears her cries and comes to her rescue.

The universal appeal of these tales is frequently attributed to the idea that they contain cautionary messages: in the case of "Little Red Riding Hood", to listen to your mother, and avoid talking to strangers. But research by anthropologist Jamie Tehrani at Durham University suggests otherwise. To work out the evolutionary history and relationships among groups of organisms, biologists compare the characteristics of living species in a process called 'phylogenetic analysis'. Tehrani has used the same approach to compare related versions of fairy tales to discover how they have evolved and which elements have survived longest.

Tehrani's analysis focused on "Little Red Riding Hood" in its many forms, which include another Western fairy tale known as "The Wolf and the Kids". He ended up with 58 stories recorded from oral traditions. First he tested some assumptions about which aspects of the story alter least as it evolves. Folklorists believe that what happens in a story is more central to the story than the characters in it. However, Tehrani found no significant difference in the rate of evolution of incidents compared with that of characters. Neither did his analysis support the theory that the central section of a story is the most conserved part.

But the really big surprise came when he looked at the cautionary elements of the story. In his analysis such elements were just as flexible as seemingly trivial details. What, then, is important enough to be reproduced from generation to generation? The answer, it would appear, is fear — blood-thirsty and gruesome aspects of the story, such as the eating of the grandmother by the wolf, turned out to be the best preserved of all. Tehrani has an idea: "In an oral context, a story won't survive because of one great teller. It also needs to be interesting when it's told by someone who's not necessarily a great storyteller. Maybe being swallowed whole by a wolf is so gripping that it helps the story remain popular, no matter how badly it's told."

Jack Zipes at the University of Minnesota is unconvinced by Tehrani's views on fairy tales. He believes the perennial theme of women as victims in stories like "Little Red Riding Hood" explains why they continue to feel relevant. But Tehrani points out that although this is often the case in Western versions, it is not always true elsewhere. In Chinese and Japanese versions, often known as "The Tiger Grandmother", the villain is a woman, and in both Iran and Nigeria, the victim is a boy.

Mathias Clasen at Aarhus University in Denmark isn't surprised by Tehrani's findings. "Habits and morals change, but the things that scare us, and the fact that we seek out entertainment that's designed to scare us — those are constant," he says. Clasen believes that scary stories teach us what it feels like to be afraid without having to experience real danger, and so build up resistance to negative emotions.

The south coast of Peru is a narrow, 2,000-kilometre-long strip of desert squeezed between the Andes and the Pacific Ocean. It is also one of the most fragile ecosystems on Earth. This is why the huarango tree is so suited to life there: it has the longest roots of any tree in the world. They stretch down 50–80 metres and, as well as sucking up water for the tree, they bring it into the higher subsoil, creating a water source for other plant life.

Dr David Beresford-Jones, archaeobotanist at Cambridge University, has been studying the role of the huarango tree in landscape change in the Lower Ica Valley in southern Peru. He believes the huarango was key to the ancient people's diet and, because it could reach deep water sources, it allowed local people to withstand years of drought when their other crops failed. But over the centuries huarango trees were gradually replaced with crops. Cutting down native woodland leads to erosion, as there is nothing to keep the soil in place. So when the huarangos go, the land turns into a desert.

For centuries the huarango tree was vital to the people of the neighbouring Middle Ica Valley too. "Of the forests that were here 1,000 years ago, 99 percent have already gone," says botanist Oliver Whaley from Kew Gardens in London, who is running a pioneering project to protect and restore the rapidly disappearing habitat. In order to succeed, Whaley needs to get the local people on board, and that has meant overcoming local prejudices. He has already set up a huarango festival to reinstate a sense of pride in their eco-heritage, and has helped local schoolchildren plant thousands of trees.

"In order to get people interested in habitat restoration, you need to plant a tree that is useful to them," says Whaley. So he has been working with local families to create a sustainable income from the huarangos by turning their products into foodstuffs. "Boil up the beans and you get this thick brown syrup like molasses. You can also use it in drinks, soups or stews." The pods can be ground into flour to make cakes, and the seeds roasted into a sweet, chocolatey 'coffee'. "It's packed full of vitamins and minerals," Whaley says.

And some farmers are already planting huarangos. Alberto Benevides, owner of Ica Valley's only certified organic farm, has been planting the tree for 13 years. He produces syrup and flour, and sells these products at an organic farmers' market in Lima. His farm is relatively small and doesn't yet provide him with enough to live on, but he hopes this will change. "The organic market is growing rapidly in Peru," Benevides says. "I am investing in the future."

But even if Whaley can convince the local people to fall in love with the huarango again, there is still the threat of the larger farms which cut across the forests and break up the corridors that allow the essential movement of mammals, birds and pollen. He's persuading farmers to let him plant forest corridors on their land. He believes the extra woodland will also benefit the farms by reducing water usage and providing a refuge for bio-control insects. "If we can do it here, in the most fragile system on Earth, then that's a real message of hope for lots of places, including Africa, where there is drought and they just can't afford to wait for rain."

La Gomera is one of the Canary Islands situated in the Atlantic Ocean off the northwest coast of Africa. This small volcanic island is mountainous, with steep rocky slopes and deep, wooded ravines. It is also home to the best known of the world's whistle 'languages', a means of transmitting information over long distances which is perfectly adapted to the extreme terrain of the island.

This 'language', known as 'Silbo' or 'Silbo Gomero', is now shedding light on the language-processing abilities of the human brain, according to scientists. Researchers say that Silbo activates parts of the brain normally associated with spoken language, suggesting that the brain is remarkably flexible in its ability to interpret sounds as language. "Science has developed the idea of brain areas that are dedicated to language, and we are starting to understand the scope of signals that can be recognised as language," says David Corina, co-author of a recent study.

Silbo is a substitute for Spanish, with individual words recoded into whistles which have high- and low-frequency tones. A whistler puts a finger in his or her mouth to increase the whistle's pitch, while the other hand can be cupped to adjust the direction of the sound. Because whistled 'words' can be hard to distinguish, silbadores rely on repetition, as well as awareness of context, to make themselves understood.

The silbadores of Gomera are traditionally shepherds and other isolated mountain folk, and their novel means of staying in touch allows them to communicate over distances of up to 10 kilometres. The study team used neuroimaging equipment to contrast the brain activity of silbadores while listening to whistled and spoken Spanish. Results showed the left temporal lobe of the brain, usually associated with spoken language, was engaged during the processing of Silbo. When the experiments were repeated with non-whistlers, however, activation was observed in all areas of the brain.

Carreiras says the origins of Silbo Gomero remain obscure, but that indigenous Canary Islanders, who were of North African origin, already had a whistled language when Spain conquered the volcanic islands in the 15th century. Whistled languages survive today in Papua New Guinea, Mexico, Vietnam, Guyana, China, Nepal, Senegal, and a few mountainous pockets in southern Europe. There are thought to be as many as 70 whistled languages still in use, though only 12 have been described and studied scientifically.

But with modern communication technology now widely available, researchers say whistled languages like Silbo are threatened with extinction. With dwindling numbers of Gomera islanders still fluent in the language, Canaries' authorities are taking steps to try to ensure its survival. Since 1999, Silbo Gomero has been taught in all of the island's elementary schools. Locals are also seeking assistance from UNESCO to declare Silbo Gomero as something that should be preserved for humanity.

The environmental practices of big businesses are shaped by a fundamental fact that for many of us offends our sense of justice. Depending on the circumstances, a business may maximize the amount of money it makes, at least in the short term, by damaging the environment and hurting people. That is still the case today for fishermen in an unmanaged fishery without quotas, and for international logging companies with short-term leases on tropical rainforest land. When government regulation is effective, and when the public is environmentally aware, environmentally clean big businesses may out-compete dirty ones, but the reverse is likely to be true if government regulation is ineffective.

It is easy for the rest of us to blame a business for helping itself by hurting other people. But blaming alone is unlikely to produce change. It ignores the fact that businesses are not charities but profit-making companies, and that publicly owned companies with shareholders are under obligation to those shareholders to maximize profits, provided that they do so by legal means. Our blaming of businesses also ignores the ultimate responsibility of the public for creating the conditions that let a business profit through destructive environmental policies.

The public can do that by suing businesses for harming them, as happened after the Exxon Valdez disaster. The public may also make their opinion felt by preferring to buy sustainably harvested products; by making employees of companies with poor track records feel ashamed; by preferring governments to award valuable contracts to businesses with a good environmental track record; and by pressing their governments to pass and enforce laws and regulations requiring good environmental practices. In turn, big businesses can exert powerful pressure on any suppliers that might ignore public or government pressure.

The public's task is therefore to identify which links in the supply chain are sensitive to public pressure: for instance, fast-food chains or jewelry stores, but not meat packers or gold miners. For example, after the US public became concerned about the spread of BSE, the US government's Food and Drug Administration introduced rules demanding that the meat industry abandon practices associated with the risk of the disease spreading. But for five years the meat packers refused to follow these. However, when a major fast-food company then made the same demands after customer purchases of its hamburgers plummeted, the meat industry complied within weeks.

To me, the conclusion that the public has the ultimate responsibility for the behavior of even the biggest businesses is empowering and hopeful, rather than disappointing. My conclusion is not a moralistic one about who is right or wrong. In the past, businesses have changed when the public came to expect and require different behavior, to reward businesses for behavior that the public wanted, and to make things difficult for businesses practicing behaviors that the public didn't want. I predict that in the future, just as in the past, changes in public attitudes will be essential for changes in businesses' environmental practices.