IELTS Academic Reading Practice Test 433

In AD 132 Zhang Heng presented the emperor with a bronze vessel unlike any that had been seen before. He was a scholar who had already earned a reputation as a poet, an astronomer and a mathematician, and he held a senior position at the Han court in Luoyang. According to the official history of the dynasty, the vessel was designed not merely to record that an earthquake had happened but to show the direction from which it had come. Zhang Heng gave it a cumbersome name, often translated as 'instrument for measuring the seasonal winds and the movements of the earth', which is why it is usually known simply as his seismoscope.

Zhang Heng was born in AD 78 and entered government service after a period of study in the capital. His talents were unusually wide: he wrote poetry and prose that later generations admired, he helped to revise the calendar, and he held the post of court astronomer, an office that combined the observation of the heavens with the interpretation of omens. He also built a water-driven armillary sphere, a model of the celestial sphere whose rotating rings showed the positions of the stars. Yet his most famous invention concerned what was happening beneath the ground.

The seismoscope was cast in bronze and shaped like a wine jar, with a domed lid and a wide body roughly two metres across. Around its outside were fixed eight dragons, their heads pointing outwards towards the eight principal directions of the compass. Each dragon held a small bronze ball in its open mouth. Directly beneath each dragon crouched a toad, also of bronze, with its head tilted back and its mouth wide open, as if waiting to catch whatever fell.

Inside the vessel, according to the Han account, was a mechanism of unknown design. When the ground shook, this mechanism released one of the balls, which dropped from the mouth of the dragon into the open mouth of the toad below. The fall was loud enough to be heard by everyone in the room, and because each dragon faced a different direction, the sound identified not only that an earthquake had occurred but where it had come from. Only one ball was released at a time, so observers could read the direction without ambiguity.

For six years the instrument apparently performed as intended, though the histories record only one dramatic test. In AD 138 the ball held by the western dragon fell. Scholars at court, who had felt nothing, declared that the device had failed. A few days later a messenger arrived from Longxi, a district more than a thousand li to the west, with news of a severe earthquake that had destroyed houses and killed people. From that day, the history observes, everyone accepted the instrument's accuracy.

The importance of such a device lay partly in Chinese ideas about government. Earthquakes were widely understood as warnings from heaven, signs that the emperor's rule had failed in some way, and the court was anxious to know where they had struck. A prompt report also allowed relief to be sent and local officials to be questioned. The instrument therefore served a political as well as a practical purpose: it gave the throne information that had previously depended on the slow arrival of messengers.

Yet the original did not survive. It was probably destroyed or lost during the political upheavals that followed the fall of the Han dynasty, and no trace of it has ever been found. All that remains is a description of a few hundred characters in the Book of the Later Han, an official history compiled by Fan Ye in the fifth century, long after the events it records. The text describes the exterior of the vessel in some detail but says almost nothing about what lay inside it.

That silence has invited speculation. The best-known reconstruction was made in the 1950s by the Chinese historian of science Wang Zhenduo, who proposed that a heavy pendulum hung at the centre of the vessel. A tremor would cause the pendulum to swing and nudge a lever, releasing the ball from the dragon on that side. Other scholars have suggested a rod balanced on a point, or a ball resting in a shallow cup, so that the slightest movement would dislodge it. No two designs are alike, and none can be tested against the original.

Critics have raised a more fundamental objection. A device sensitive enough to detect a tremor several hundred kilometres away, as the story of 138 requires, would surely also be triggered by the rumble of carts, the movement of people or the settling of a large building. Its reputation for reliability is therefore difficult to explain, and it is telling that the histories record only a single successful detection. Some historians suspect that the account has been polished in the telling, or that the instrument worked only under favourable conditions that are no longer known.

None of this has diminished Zhang Heng's standing. In China he is remembered as one of the greatest scientists of the ancient world, and replicas of his instrument are displayed in museums in Beijing and elsewhere. A crater on the Moon and a minor planet both carry his name. More importantly, the idea behind the device, that the movements of the earth can be measured by an instrument rather than merely endured, was not to be pursued again on a large scale for more than fifteen centuries.

We have no organ for time. There is no patch of the brain that responds only to duration, in the way that the retina responds to light, and no nerve that carries a signal meaning 'one second'. Instead, our sense of how long something lasts appears to be assembled from several separate systems. One of these keeps the body's daily rhythms in step with daylight. The other, which handles intervals from a fraction of a second to a few minutes, is the system psychologists usually mean when they speak of time perception, and it is the one that can be studied in a laboratory.

The dominant explanation of interval timing is the internal clock, proposed in various forms from the 1960s onwards and still the starting point for most experiments. A pacemaker is said to emit pulses at a steady rate; a switch closes when a timed event begins and opens when it ends; an accumulator counts the pulses that get through; and a comparator matches the total against durations stored in memory. The model also explains a curious feature of timing. Our estimates of long intervals are proportionally no better than our estimates of short ones, a pattern known as the scalar property.

Physiological evidence gives the model some support. The neurotransmitter dopamine has been repeatedly implicated in timing. People with Parkinson's disease, in which dopamine-producing cells are lost, tend to underestimate intervals of a few seconds. Their judgements shift when they begin taking medication that restores dopamine levels. Timing also depends on the cerebellum and on regions of the parietal cortex. The rate of the supposed pacemaker is not fixed: it appears to vary with arousal and with body temperature, which may be one reason why the hours of a feverish afternoon are so hard to judge.

Attention matters at least as much as chemistry. If pulses from the pacemaker are counted, then anything that distracts us should reduce the count and make an interval feel shorter, and this is broadly what happens. Time flies during absorbing activity, while a dull wait, when there is nothing to attend to but the passing of time itself, drags almost unbearably. Experiments confirm the pattern: people asked to do a demanding task while judging a duration give shorter estimates than people whose attention is free to wander.

Novelty has a striking effect. In one well-replicated finding, an unfamiliar image shown for the same length of time as a familiar one is judged to have lasted longer, an effect usually called the oddball illusion. A related curiosity is the stopped-clock illusion. When the eyes move quickly to a clock, the first tick appears to last longer than the ticks that follow, presumably because the brain fills the brief gap in visual information with the image it receives afterwards.

Memory pulls in the opposite direction. A week of routine leaves few distinct traces, and when we look back on it, it seems to have gone quickly; a holiday packed with new places and experiences feels, in retrospect, long. Some researchers argue that retrospective judgements rest on the number of separate events we can recall, so that a period rich in novelty is judged to have lasted longer. This helps to explain a common complaint of later life: as new experiences become rarer, whole years seem to slide past.

Older adults frequently report that time is accelerating. The most popular explanation is proportional: for a ten-year-old, a year is a tenth of everything experienced so far, whereas for a fifty-year-old it is a fiftieth. Attractive as this is, the arithmetic is not a mechanism, and laboratory studies of interval timing find only modest differences between age groups. The effect seems to lie in memory and attention rather than in the clock itself, which is why it is reported most often by people whose days have become predictable.

The clock can also be tested by removing the cues that normally reset it. In the 1960s the German physiologist Jürgen Aschoff kept volunteers in an underground bunker where neither daylight nor clocks were available. Their sleep-wake cycles drifted, settling at close to twenty-five hours rather than twenty-four. The French explorer Michel Siffre lived for months in caves and reported a similar lengthening, together with a growing inability to judge how much time had passed. Such experiments show that the internal clock is approximate and that it is normally corrected, day by day, by light.

Strong emotion distorts time too. Drivers involved in accidents often say that the moment of impact stretched out, as though they had seen everything in slow motion. Careful tests suggest that they did not: people asked to judge rapidly changing images under stress do not actually process them faster, and the impression of slowness is probably constructed afterwards, when a frightening event is remembered in unusually dense detail. Emotion may therefore affect the memory of an interval more than the interval itself.

These findings are not merely curiosities. Eyewitnesses routinely estimate how long a crime or an accident lasted, and their estimates can be wildly wrong. Anaesthetists need to know whether a patient's sense of time is affected by drugs. Designers of everything from hospital waiting rooms to railway information boards trade on the fact that an explained delay feels shorter than an unexplained one. The study of time perception, in other words, tells us less about the world than about the machinery that allows us to live in it.

In most English-speaking countries the board of a public company is chosen by its shareholders and answers to them. Employees may be consulted through unions or staff councils, but they do not sit at the table where strategy is decided. In much of continental Europe the arrangement is different. Germany, Sweden, Denmark, Austria, France and several other countries require some large companies to reserve seats on the board for representatives elected by the workforce. Whether other countries should follow is usually argued as a contest between owners and workers. It is better understood as a question about what a board is for.

The German system is the best known. Under a law passed in 1976, companies with more than two thousand employees must give half the seats on their supervisory board to representatives of the workforce, while firms with between five hundred and two thousand employees give them a third. The arrangement is less equal than it appears, because the chairman, who is chosen by the shareholders' side, has a casting vote when the board is evenly divided. German companies also have two boards: a supervisory board oversees a separate management board, so worker representatives monitor the managers rather than running the business from day to day. Similar arrangements, usually with a smaller share of the seats, exist in the Nordic countries.

Supporters of worker directors begin with the nature of employment. A shareholder can spread an investment across hundreds of companies and sell it in seconds; an employee who has spent fifteen years learning the ways of one firm cannot diversify in the same way, and loses far more if the firm fails. Employees also know things that directors often do not: which machines are unreliable, which customers are unhappy, which managers are trusted. On this view, giving them a voice on the board is not charity but a way of bringing information and a longer time horizon into decisions that are otherwise dominated by financial markets.

Employers' organisations and many investors reply that the costs are real. A board that must satisfy two constituencies may take longer to reach decisions, and representatives may face a conflict of interest when the choice lies between higher wages and new investment. Critics also fear that worker directors will resist closures and restructuring that the company needs in order to survive, and that confidential information discussed at board level will be harder to protect. Some argue, too, that a director elected by one group will find it difficult to act in the interests of the company as a whole, as the law requires. If capital can earn the same return elsewhere with fewer constraints, they add, some of it will go elsewhere.

The evidence gives little comfort to either side. Economists have compared German firms just above and just below the size thresholds set by the 1976 law, and the most careful of these studies found that board representation made little measurable difference to wages or to profitability, although it appeared to be associated with a modest increase in investment. The predicted disasters did not occur, but neither did the transformation that supporters promised. Most of this research concerns Germany, however, and its findings are hard to transfer to countries where companies have a single board and where unions play a different role.

Trade unions themselves have not always been enthusiastic. Some British unions in particular have long been wary of a seat on the board, fearing that a representative would be drawn into responsibility for unpopular decisions, such as redundancies, without the power to change them. In this view the proper place for workers' interests is collective bargaining, in which the two sides negotiate openly from separate positions, rather than a boardroom in which a small minority of employee directors can be outvoted while appearing to give their consent. Others reply that collective bargaining has itself weakened as union membership has fallen, which makes a guaranteed voice more attractive than it once was.

Governments that have tried to introduce the idea elsewhere have moved cautiously. In 2018 the code of corporate governance in the United Kingdom asked large listed companies to adopt one of three methods of hearing the workforce: appointing a director from among the employees, creating a formal advisory panel, or naming a non-executive director with special responsibility for staff. Most companies chose the last of these, which changed the least. In the United States, proposals to give workers a substantial share of board seats in the largest companies have been put forward but have not become law.

My own view is that a modest requirement is justified. Large companies should reserve a minority of seats, perhaps a third, for directors elected by the workforce, and those directors should receive proper training and carry the same legal duties as their colleagues. I would not insist on equal numbers, which risks paralysis in companies that have only one board. The strongest argument for the reform is not that it hands control to employees, but that worker directors can provide information that boards would otherwise lack, and that decisions taken with them in the room are more likely to be accepted by the people who must carry them out. Such a reform would not end disputes between managers and staff, and it should not be presented as if it would.