IELTS Academic Reading Practice Test 477

The Amazon river dolphin, known in Brazil as the boto, is the largest of the world's river dolphins. Adults typically reach about two and a half metres in length and may weigh well over a hundred kilograms, with males noticeably bigger than females — an unusual pattern among cetaceans, in which the female is more often the larger sex. The species is found throughout the Amazon and Orinoco river systems, in Brazil, Peru, Bolivia, Ecuador, Colombia and Venezuela, and its range covers an area larger than Western Europe.

Its body is less streamlined than that of an ocean dolphin. Instead of an upright dorsal fin it carries a low ridge, or hump, on its back, and its beak is long and slender, lined with stiff hairs when the animal is young. The most striking feature is the neck: unlike other dolphins, whose neck vertebrae are fused into a rigid block, the boto's remain separate, allowing it to bend its head from side to side. That flexibility is invaluable in the flooded forest, where the animal must weave between submerged trunks and branches.

Colour varies strikingly with age and between individuals. Calves are grey, and many adults remain grey, but a large proportion acquire a mottled or vivid pink hue, especially on the belly, the face and the tips of the fins. The pink is not a pigment: it comes from blood vessels close to the surface of the skin, and it becomes more visible when the animal is active and its circulation quickens. Scars and tooth marks, which heal in pink, add to the effect. Because the colour changes, early observers mistook the different shades for different species.

The boto's eyes are small, but it is not blind, and in clear water it appears to see well. Its principal sense, however, is hearing. Like other toothed whales, it produces a rapid series of clicks and reads the returning echoes, a process known as echolocation that allows it to locate fish and to find its way through water so muddy that visibility is measured in centimetres. The rounded organ on its forehead, the melon, focuses the sound. The bristles on a young animal's beak may also have a sensory function, though this remains uncertain.

The Amazon's water level is among the most variable in the world. Between the low-water season and the flood, the river can rise by ten metres or more, and the forest that borders it is transformed into a drowned landscape of submerged trees. The dolphins follow the water into this forest, swimming among the trunks and roots in search of prey; they have been seen moving through the trees at a considerable distance from the main channel. When the water falls, they retreat to the river itself. This seasonal movement makes the species unusually hard to count, since animals scattered through the trees in June may be concentrated in a few channels in December.

Amazon river dolphins eat fish, and a great many kinds of them: studies of stomach contents have identified several dozen species, ranging from small surface-dwelling forms to armoured catfish that live on the bottom. They also take river crabs and, occasionally, small turtles. Their teeth are unusual among dolphins in being differentiated, with pointed front teeth for seizing prey and flatter back teeth for crushing. Hunting is often solitary, though groups sometimes cooperate to drive shoals of fish towards a bank, and the animals are active by both day and night.

Little is known about breeding. Calves appear to be born after a gestation of roughly eleven months, and a single calf is usual. Mothers have been observed with calves in quiet backwaters, and the pair stays close for a long period. Females with young calves are seldom seen in open water, which may explain why births are so rarely recorded.

The species faces several pressures, none of them easy to reverse. The most widespread is accidental entanglement in fishing nets: the dolphins must surface to breathe every few minutes, and an animal caught in a gillnet drowns. Dams built for hydroelectricity cut rivers into fragments and separate populations, while gold mining releases mercury, which accumulates in the fish the dolphins eat and then in the dolphins themselves. In parts of Brazil the animals have also been killed deliberately, chiefly to provide bait for a type of catfish sold in neighbouring countries, a trade that campaigns have so far failed to stop.

In the folklore of river communities the boto is a shapeshifter. It is said to appear at parties as a handsome stranger, recognisable only by the blowhole on the top of his head, and to father children who are never seen. Whatever the ecological accuracy of such tales, they have given the animal a protected place in local culture that a purely scientific argument could hardly supply.

For a long time the boto was assumed to be widespread and therefore safe. Surveys have since shown that populations are declining, and in 2018 the species was listed as Endangered by the International Union for Conservation of Nature. That assessment, and the attention it brought, marked a turning point in how the animal is studied and managed.

Sarcasm is the act of saying one thing while intending another, usually the opposite. A colleague who surveys a disastrous piece of work and calls it impressive is not offering praise. The remark is ironic, and its point depends on the listener recognising that the words are not to be taken at face value.

Sarcasm of this kind is common in conversation, though estimates of how common vary widely, partly because researchers disagree about what should count. It appears in every language in which it has been studied, but the forms it takes differ considerably from one place to another. A remark can also be sarcastic and affectionate at the same time, which is one reason the phenomenon is so hard to define.

What makes sarcasm puzzling is that understanding it seems to require more work than understanding a plain statement. According to the account that dominated linguistics for decades, a listener first computes the literal meaning of an utterance, notices that it conflicts with the situation, and then infers the meaning the speaker intended. This two-stage model, associated with the philosopher H. P. Grice, treats irony as a deliberate flouting of the expectation that speakers will be truthful and relevant. On this view the literal meaning is always processed first, even when it is obviously wrong.

Experiments have not consistently supported that picture. Work by the psycholinguist Raymond Gibbs and others in the 1980s and 1990s suggested that readers and listeners can arrive at a figurative interpretation as quickly as a literal one, and that in a supportive context they may never entertain the literal meaning at all. If that is right, sarcasm is not a puzzle the mind solves after a delay; it is understood much as any other remark is, with context doing most of the work.

A different approach, proposed by Dan Sperber and Deirdre Wilson in the 1980s, holds that irony is essentially an echo. On their account the speaker is not asserting the opposite of what is meant but repeating, in a sceptical tone, a thought or expectation attributed to someone else — often to the person being addressed, or to a hope that has just been disappointed. The sarcastic colleague is echoing the expectation that the work would be good. This theory explains why irony so often carries a note of mockery without any explicit criticism.

In speech, listeners have several kinds of evidence to draw on. The most obvious is tone of voice. Sarcastic remarks tend to be slower than sincere ones, are often pitched lower, and may carry unusual patterns of stress. Yet these signals are unreliable on their own: the same intonation can accompany genuine enthusiasm, and people vary in how much they use it. Facial expression and gaze help; a slight smile or a delay before responding can signal that the words are not to be trusted. Context, however, is the strongest clue. If the situation plainly contradicts what is being said, listeners rarely need anything else.

The relationship between speaker and listener matters too. Sarcasm between strangers is risky, because the listener may not know the speaker well enough to judge the intention, and may take offence. Between people who know each other, it can be a form of intimacy, a way of signalling that both parties share the same view of a situation. Some researchers have argued that this is one reason sarcasm survives despite its capacity to wound: used among allies, it can draw a group together rather than divide it. In a formal setting, by contrast, the risk of giving offence usually outweighs any gain in wit.

Clinical studies have shown how much the skill depends on social understanding. People who have suffered damage to the right side of the brain often fail to detect sarcasm, taking remarks literally and complaining of rudeness where none was intended. Many autistic adults report similar difficulty, though the picture is not uniform and depends heavily on how well they know the speaker. Children acquire the ability gradually: most can recognise simple cases by the age of six or seven, but appreciating subtler forms of irony may take several more years. Some studies report that accuracy declines again in later life, though the evidence for this is mixed.

Written messages pose a special problem, because tone of voice is missing. Writers compensate with exaggeration, capital letters or a deliberately flat phrase of praise. On social media, users have invented their own signals, including hashtags and the '/s' tag that tells readers a remark is ironic. Emoticons help, but imperfectly: a smiling face may soften a sarcastic comment or may itself be part of the joke, and readers frequently misjudge which. Studies of online communication have found that sarcasm is misunderstood more often than people assume, even among close friends.

Whether sarcasm is a good thing is a separate question. In one experiment published in 2015, volunteers who had been asked to recall a sarcastic exchange went on to produce more original solutions to a creativity task than those who recalled a sincere one; the effect appeared only when the people involved trusted each other. That finding is intriguing, but it rests on a small number of studies, and humour of this kind can just as easily humiliate as amuse. The safest conclusion is that sarcasm is a demanding skill, both to produce and to interpret, and that researchers remain some way from a full account of how it works.

In September 2014, schools in England replaced their lessons in information and communication technology with a new subject called computing. The change was notable less for its content than for its timing: the programmes of study set out expectations for children from the age of five, who were to be taught what an algorithm is and how to write and test simple programs. England was not alone. Two years earlier, Estonia had launched a scheme to introduce programming in primary schools, beginning with seven-year-olds, and several other countries have since followed. The question such policies raise is not whether programming is worth learning, but whether five is a sensible age at which to begin.

The case in favour rests on two claims. The first is economic. Software is now embedded in almost every industry, and the software industry itself has argued that most future jobs will require at least a working knowledge of how programs are constructed; waiting until secondary school, it is said, leaves too little time. The second claim is educational. In a widely cited article published in 2006, the computer scientist Jeannette Wing argued that learning to program fosters computational thinking — a set of habits, including decomposition, abstraction and the systematic testing of ideas, that is useful far beyond the computer. On this view coding is a vehicle for a general intellectual discipline, and the language used matters less than the thinking it demands.

Developmental psychologists are more cautious. Their objection is not that young children cannot use computers — most can, and many enjoy it — but that the particular demands of formal programming arrive too early. In the standard account of cognitive development, children between roughly two and seven reason about concrete objects and events far better than about abstract rules, and the ability to hold several hypothetical possibilities in mind at once comes later. A five-year-old can give a friend a precise sequence of instructions and grasp that order matters, which is the essence of an algorithm. What a five-year-old finds much harder is the syntax of a text-based language, where a missing bracket stops everything, and the patience to trace an error back through many steps.

A second group of sceptics, researchers who study transfer of learning, ask a narrower question: does learning to program make anyone better at anything else? The hope behind many of these policies is that it does — that computational thinking will show up in mathematics, in science, in careful reasoning generally. Reviews of the evidence have been consistently disappointing. Studies often find modest gains on tasks closely resembling programming and little or nothing elsewhere, and the more distant the skill being measured, the smaller the effect. This is not an argument against teaching programming; it is an argument against justifying it by benefits that have not been shown.

The practical objection is simpler. A curriculum is only as good as the people teaching it, and in England the supply of specialist computing teachers has not kept pace with the change. A report by the Royal Society in 2017 found that a large proportion of those teaching the subject had no qualification in it, and teachers' professional organisations have repeatedly warned that primary staff, trained in a broad range of subjects, are being asked to teach material they have never studied themselves. Where the teacher is unsure, lessons tend to collapse into the use of software rather than the understanding of ideas.

There is also a question of fairness. Campaigners for equal access to technology point out that a child who has a computer at home, and an adult willing to help, arrives at school with an advantage that grows with every year of instruction. The pattern is visible in participation: far fewer girls than boys in England choose to continue with computer science after the age of fourteen, and the imbalance has proved stubborn. Making programming compulsory may look egalitarian, but if lessons assume equipment and support that some families cannot provide, they can widen the gap they were meant to close.

None of this means that five-year-olds should be kept away from the subject. It means that what happens in the first years should look different. A collection of teaching materials known as Computer Science Unplugged, developed in New Zealand in the 1990s, shows that many central ideas can be taught without a computer at all: children can sort cards to grasp how information is stored in order, or follow a friend's instructions to discover what an ambiguous step does. Much of this is done through play. Block-based languages, in which commands are dragged into place and cannot be mistyped, remove the syntax barrier while leaving the logic intact, and they are already common in primary classrooms. The most promising lessons connect programming to subjects children already study, so that a program becomes a way of answering a question about a plant's growth or a shape's angles.

My own view is that five is neither too early nor the age at which the argument should be settled. What five-year-olds need is not a programming language but an introduction to the ideas that languages express: sequence, repetition, condition, and the discovery that a machine does exactly what it is told and nothing more. Formal syntax can wait until children are older. A country that wishes to teach coding to infants would do better to invest in teacher training and reliable equipment, and to write modest targets into its curriculum document, than to announce ambitious ones and leave the classroom to manage as best it can.