IELTS Academic Reading Practice Test 105

Christopher Columbus first encountered the pineapple on his second voyage. In November 1493 his ships reached Guadeloupe, in the Lesser Antilles, and the crew found a fruit that the islanders cultivated and ate. It was large, golden and fragrant, and it resembled a pine cone, which is why the Spanish called it piña. Columbus's account, published in the years that followed, made the fruit known in Europe, but knowing about it and tasting it were very different matters. The pineapple was a tropical plant, and nothing in the climate of Spain or Italy resembled the conditions in which it grew.

Fresh fruit loaded aboard ship rarely survived the return crossing, and most of those that did arrive were already decaying. Sailors tried cutting the fruit unripe, wrapping it in cloth and storing it in vinegar, but the results were poor. Shippers also lacked any way of keeping the fruit cool: the holds of sixteenth-century vessels were warm and humid, ideal for mould. For much of the sixteenth century the pineapple remained a report rather than a commodity, a fruit described by travellers and almost never seen on a European table.

Spanish and Portuguese ships nevertheless carried the plant across the tropics. It reached the Philippines, parts of Africa and eventually the Pacific islands, where it fitted easily into existing gardens. In the Americas the fruit had long been cultivated, and its spread was part of the wider exchange of crops that followed European contact. The plant's tolerance of heat and its readiness to produce suckers made it simple to propagate, and this helped it to travel.

Botanically the pineapple is not a simple fruit. It is a multiple fruit, formed from dozens of individual flowers whose ovaries fuse as the stem thickens; each 'eye' on the surface marks a flower. The plant also produces side shoots, or suckers, and a crown of leaves at the top of the fruit, either of which can be used to start a new plant. These features made it easy to carry cuttings between colonies and to establish the plant wherever there was warmth and moisture.

Northern Europe was a harder proposition. By the late seventeenth century, gardeners in the Netherlands were fruiting the plant in heated glasshouses, and wealthy landowners in Britain soon built similar structures, known as pineries. Heat came from fermenting tan, the bark left over from leather working, or from horse manure packed into pits beneath the plants. Flues carrying smoke from fires, and later pipes of hot water, warmed the air, while glass admitted the weak northern light. A successful pinery was a feat of engineering as much as of horticulture. The earliest structures were little more than pits covered with glass, but by the eighteenth century pineries were attached to walled gardens and heated by systems of flues.

Such buildings were expensive to build and costly to run. A pineapple house consumed fuel and labour all year, and a single fruit might represent months of attention. Gardeners had to regulate temperature and humidity, shift the plants between beds and protect them from pests. The fruit was, in consequence, far too valuable to be treated as ordinary food. Only the wealthy could justify such expenditure, and many owners treated the fruit as a gamble whose success depended on the skill of a single gardener.

The pineapple became a symbol of status rather than a foodstuff: it was displayed at banquets, carved above doorways and reproduced in porcelain. Hosts would place a single fruit at the centre of the table, where it announced that the household could afford a heated glasshouse and the staff to run it. In this way a plant from the Caribbean became an ornament of the European country house, and its image outlived the practical difficulty of growing it.

Meanwhile the fruit had reached Hawaii, where it was grown in small plots long before the canning industry appeared. In 1901 James Dole founded the Hawaiian Pineapple Company and built a cannery near Honolulu. He planted thousands of acres, organised the harvest and persuaded investors that fruit could be processed on an industrial scale. Canned pineapple was cheap, sweet and easy to transport, and it found markets in North America and Europe. The company recruited workers from several countries, and the crop became one of the islands' major exports. A mechanical peeler and corer, introduced in the 1910s, allowed the cannery to handle fruit far faster than hand labour.

Refrigeration and faster ships eventually made fresh pineapples available in European shops, but the canned product had already changed the fruit's place in the diet. It moved from the banquet table to the kitchen shelf, used in cakes, salads and sauces. The pineapple had completed a journey from exotic curiosity to everyday ingredient. By the middle of the twentieth century, the canned rings and chunks had become standard ingredients in both home baking and commercial food manufacture.

Traces of the older world survive. Walled gardens with pineapple pits can still be visited, and the fruit remains an emblem of hospitality on gates and pub signs. The plant that once required a furnace now arrives in supermarkets at any season, yet the expense and ingenuity of its European history are easily forgotten. The pineapple's history in Europe is thus a record of what wealth and technology could do with a plant that nature had placed on the other side of the world.

Few kinds of animal behaviour are as easy to recognise and as hard to define as play. A litter of puppies chasing one another, a young goat leaping from a rock and a crow dropping a stone again and again all look like play, yet none of these activities produces food, attracts a mate or defends a territory. Biologists have therefore defined play by its manner rather than its purpose: behaviour that appears to have no immediate function, that is repeated but not rigidly stereotyped, that is exaggerated or incomplete, and that occurs only when an animal is fed, safe and free from stress. The American biologist Gordon Burghardt has set out a series of criteria of this kind and argued that behaviour should be called play only if it meets all of them.

Play takes several forms. Locomotor play consists of running, jumping, twisting and chasing with no obvious destination, and is typical of young mammals such as lambs and foals. Object play involves manipulating something — a stick, a stone, a feather — and is common among birds, notably crows and keas. Social play, the rough-and-tumble wrestling of young mammals, is the most studied of all, perhaps because it is the easiest to record. Nor is play confined to warm-blooded animals with large brains. In 2022 a team at Queen Mary University of London reported that bumblebees would repeatedly roll small wooden balls, apparently without any reward; the researchers were cautious, but argued that the behaviour met several of the standard criteria.

Play is also risky. Young animals that leap, wrestle and chase use a great deal of energy at the very time when they need it for growth, and they make noise and lose vigilance, which attracts predators. Studies of animals in the wild have found that play becomes less frequent when food is scarce or when predators are near, as though it were a luxury that can be postponed. Play carries the further risk of injury: a young animal that breaks a leg while leaping has little chance of surviving to breed. An activity with such costs must, evolutionary biologists reason, bring some compensating benefit, or it would long ago have been abandoned.

Several benefits have been proposed. The oldest suggestion is that play is practice: young animals rehearse the skills they will need as adults, whether hunting, fighting or escaping. A second is that social play teaches animals to read signals and to cope with unexpected behaviour from others. A third is that play builds cognitive flexibility, the ability to switch between strategies, by exposing young brains to unpredictable situations. None of these explanations excludes the others, and most researchers now suspect that play serves more than one purpose. Which of them matters most may well depend on the species, and even on the individual.

Direct evidence is hard to obtain, but experiments on laboratory rats have been influential. Sergio Pellis and his colleagues at the University of Lethbridge in Canada have compared young rats allowed to play with others and rats kept apart from companions, so that they cannot wrestle. The deprived animals developed differently: the prefrontal cortex, a region involved in planning and in regulating social behaviour, matured in an altered way, and the rats responded less flexibly to unfamiliar animals when they grew up. Because rats play in a characteristic way, with the larger animal often deliberately putting itself at a disadvantage, the researchers could also study how each pair negotiates every move.

Comparative studies support a link with brains and with time. An analysis of play across mammals and birds found that species which play more frequently tend to have larger brains in relation to their body size, and that play is most elaborate in species with long juvenile periods, during which the young depend on adults for food and protection. Species that mature quickly and begin breeding in their first year, by contrast, play comparatively little. Play is not, however, only for the young. Dolphins, chimpanzees and some parrots continue to play as adults, and in these species play appears to maintain social relationships rather than to train skills for later use.

Because play resembles fighting or mating, animals need ways of announcing their intentions. Canids, including wolves, coyotes and domestic dogs, use a play bow — the front legs down, the rear end up — which invites the partner to continue and signals that a bite or a pounce is not serious. A dog that breaks the rules, for instance by biting too hard, is likely to be met with a pause or an end to the game. Such signals allow animals of very different size and strength to play together.

Studying play is nevertheless frustrating. Much of the evidence comes from captive animals, which may play more or less than wild ones, and observation in the field is difficult because play is sporadic and often brief. It is also hard to separate the effects of play from those of exercise, social contact and exploration, since young animals prevented from playing are usually prevented from doing other things as well. After decades of research, the question of why animals play has not been answered so much as broken into smaller questions.

Few pieces of office furniture have acquired a moral character as quickly as the chair. Workers are told that sitting is the new smoking, that their desks are killing them, and that the remedy is a desk that rises so they can stand. My own view is that a sit-stand desk can be a useful device for interrupting long periods of stillness, but that it is not a solution to the problem of inactivity. Much of the confidence behind the fashion rests on a misreading of evidence that is more ambiguous than the advertisements suggest.

The most quoted study is older than most of the furniture. In the early 1950s Jerry Morris and his colleagues compared drivers and conductors on London buses. Drivers sat for most of their shift, while conductors climbed stairs and walked along the aisle. The researchers found that drivers had higher rates of coronary heart disease than conductors, and the difference was not explained by age or social class. The result was striking, and it helped to establish the idea that physical activity protects the heart. It was one of the first studies to link the demands of a job, rather than leisure habits, with heart disease.

The study is often cited as proof that sitting kills, but it compared active work with sedentary work; it did not isolate sitting from overall physical activity. Conductors were climbing stairs for hours, not merely standing. A worker who uses a standing desk and stays at it without moving is not doing what the conductors did. The distinction matters, because it shifts attention from posture to movement. Standing still at a desk is a static posture, and static postures were not what raised the conductors' activity levels.

Later research on sedentary behaviour has produced a large body of evidence linking long periods of sitting with higher mortality. Much of this evidence comes from questionnaires and is confounded by diet, income, smoking and leisure exercise. People who sit for long hours at work may also be people who drive to work, eat hurriedly and take little exercise at weekends. No trial has yet shown that a sit-stand desk prevents a heart attack or a stroke. The association is real enough to justify concern, but it does not tell us that a particular piece of furniture will save anyone.

Trials of sit-stand desks are numerous but usually small and short. They generally show reductions in sitting of an hour or two per day, and some report less discomfort in the back and neck. Few last long enough to test disease, and results for weight are modest or absent. A review that pools such studies may find statistically significant improvements, but significance is not the same as importance. The evidence is best described as promising for comfort and thin for everything else. Many trials also rely on volunteers who are already interested in the question, which can make the results look more encouraging.

Standing does burn more energy than sitting, but the difference is small, perhaps a few dozen calories over a working day, and it is easily offset by a biscuit. Nor is standing itself free of risk: prolonged static standing can cause discomfort in the legs and back, and it may worsen varicose veins. The body seems to dislike any posture held too long, whether seated or upright.

People may also compensate. Standing at work can leave them tired, or they may sit more at home; some trials find no overall increase in movement. A device that changes one hour of the day may be cancelled by changes elsewhere. This is why studies that measure only time at the desk can exaggerate the benefit of the device they are testing. A worker who feels virtuous after standing for an hour may reward themselves with a longer sit at lunchtime.

The reasonable conclusion is that the standing desk is a tool for interrupting stillness rather than a treatment for disease. Its value depends on changing posture frequently and on movement, not on standing still. A worker who alternates between sitting, standing and walking every half hour is probably better off than one who remains seated all morning; a worker who stands motionless for three hours has merely exchanged one form of inactivity for another. The goal is not an upright body but a body that changes position often.

Workplaces should therefore offer choice rather than compulsion. Employers can provide height-adjustable desks, but they should also encourage short walks, stairs and meetings on foot. Public health messages should emphasise activity rather than furniture, because a desk cannot supply the exercise that the bus conductors obtained from their work. The aim is not to make everyone stand, but to make prolonged stillness less normal. Simple changes, such as placing printers at a distance or shortening meetings, can do more than a piece of equipment.

None of this means that sit-stand desks are worthless. They can ease discomfort, and for some workers they make a day at a screen more tolerable. But the claims made for them have outrun the evidence, and a sense of virtue is not the same as health. The chair is not the enemy; the real enemy is the unbroken hour. If a desk helps a worker to move more often, it has done its job; if it merely changes the shape of stillness, it has not.