IELTS Academic Reading Practice Test 116

For most of the twentieth century, calculation was done by machine but not by pocket machine. Mechanical calculators, whose gears were turned by a hand crank or a small electric motor, occupied a corner of a desk and weighed several kilograms. The best of them could multiply and divide, but they were expensive, noisy and easily jammed, so only businesses, laboratories and government offices could justify the cost. Adding up a column of figures in an office was a skilled job, and in a large firm it belonged to a specialist operator. In a smaller business the work fell to a clerk, who was expected to check the result by repeating the whole calculation.

The first all-electronic desktop calculator, the Anita Mark VII, was launched in Britain in 1961 by Bell Punch, a company that had previously made mechanical adding machines. It performed its arithmetic with hundreds of cold-cathode tubes — glass valves that conduct electricity and glow as they do so — and it displayed its results on a row of similar tubes. Compared with a mechanical calculator the machine was fast and almost silent, but it was the size of a large cash register, it produced a good deal of heat, and it cost about as much as a small car. Maintenance was a constant problem, since a single failed valve could silence the machine.

The transistor changed the economics. A transistor is a small solid device that can switch or amplify an electric current, and it replaced the valve with something cheaper, cooler and far more reliable. In 1964 the Japanese company Sharp introduced the Compet 10, an all-transistor calculator that was smaller and more dependable than anything before it. Rival firms in Japan, the United States and Europe hurried out competing machines, and within a few years the electronic calculator had become ordinary office equipment rather than a specialised instrument. Sales grew quickly, and several long-established makers of mechanical machines either converted their factories or closed.

The next step was integration. Instead of wiring together thousands of separate transistors, manufacturers learned to etch a complete circuit onto a single chip of silicon, and the number of components that a chip could hold rose rapidly year by year. In 1967 engineers at Texas Instruments built a handheld prototype under the project name 'Cal Tech'; it fitted into a hand but weighed about a kilogram and a half, because the batteries of the period were heavy. Two years later Sharp's QT-8D used large-scale integrated circuits and could be lifted with one hand.

The true pocket calculator arrived in 1971. A Japanese company, Busicom, had asked a small Californian firm called Intel to design a set of chips for its desktop machines, and Intel's engineers, working with Busicom's Masatoshi Shima, succeeded in compressing the central processing unit of a computer onto a single chip. That chip, the 4004, is generally regarded as the first microprocessor, and it went into Busicom's desktop calculators. The same year Busicom launched the Handy, built around a single calculator chip from another American firm, Mostek; it is usually described as the first pocket calculator, since it ran on batteries and could be carried in a coat pocket.

Pocket calculators were at first still costly and limited in what they could do. The Hewlett-Packard HP-35, introduced in 1972, changed that. It was the first pocket machine able to calculate trigonometric and logarithmic functions, which scientists and engineers had previously obtained from printed tables or from a slide rule. At 395 dollars it was not cheap, but it produced in a second a result that took a slide rule far longer, and it is often credited with hastening the disappearance of the slide rule from classrooms and laboratories.

Competition then drove prices down with extraordinary speed. Sinclair Radionics, a British firm, produced a calculator slim enough to slip into a shirt pocket and powered by small button cells, and Japanese manufacturers fought each other on cost. Within a few years a basic four-function calculator sold for a fraction of the price of the HP-35, and by the late 1970s such devices were being given away as promotional gifts. In 1973 Sharp introduced one of the first calculators to use a liquid-crystal display, which consumed far less power than the glowing red light-emitting diodes it replaced.

The consequences reached well beyond the office. Bookkeepers and shop assistants no longer needed to perform long multiplication by hand. Schools argued over whether pupils should be allowed to use calculators in examinations; many mathematics teachers insisted that children must still learn arithmetic without them, and rules changed only gradually, with calculators permitted in some papers and forbidden in others. Makers of slide rules and printed mathematical tables, whose products had been standard equipment for engineers, saw their markets vanish, and by the early 1980s a generation of engineers had grown up who had never learned to use one.

Later developments pushed the calculator further. Programmable pocket models of the mid-1970s could store a sequence of instructions and repeat it, and graphing calculators, which draw curves on a small screen, became standard tools in secondary schools and universities. The final stage has been absorption: the calculator is now a minor function of a mobile phone, and the dedicated pocket calculator survives mainly where a cheap, robust, single-purpose device is still wanted.

Powered exoskeletons are machines that a person wears. A frame runs alongside the legs, arms or back, and motors at the joints supply part of the force needed to stand, walk or lift a load. The idea is not new: inventors were filing patents for devices intended to help a person walk before 1900, and the mechanical suit has been a fixture of science fiction for a century. What has changed is that the components — compact electric motors, strong lightweight composites, cheap sensors and fast control electronics — have only recently become good enough for such machines to leave the laboratory and enter hospitals, factories and research centres.

The engineering problem is not simply one of adding power. A human leg is an efficient system that stores energy in its tendons as the foot lands and releases it as the body moves forward, and a clumsy motor can disrupt this pattern as easily as assist it. Designers therefore distinguish between two approaches. A rigid exoskeleton is attached to the wearer at a few points, usually the foot, the shin and the waist, and its joints must be aligned closely with the wearer's own, because any mismatch produces pressure on the skin and unwanted forces on the knee. A soft exosuit, by contrast, uses fabric, straps and cables rather than a frame of metal or carbon fibre, and pulls on the limb rather than replacing its structure.

Every powered device must also decide when to help. The simplest controllers replay a fixed walking pattern, beginning each step at a set moment and adjusting only the speed to the wearer. Better systems infer the wearer's intention from sensors: strain gauges built into the frame, pressure sensors in the shoe, gyroscopes that measure how the body is tilting. Because the wearer's muscles remain in charge, a machine that pulls at the wrong moment is worse than no machine at all. A few devices go further and listen to the body directly. The HAL suit, developed by Yoshiyuki Sankai and his colleagues at the University of Tsukuba in Japan, detects the faint bioelectric signals that travel from the nervous system to the muscles and uses them to time its assistance.

Power is the constraint that shapes everything else. Motors must be light, and every battery adds mass that the wearer has to carry when the machine is switched off. Hydraulic actuators, which push fluid through pipes to produce large forces, were used in the earliest machines; the Berkeley Lower Extremity Exoskeleton, built at the University of California with funding from the American defence research agency DARPA, was a hydraulically powered frame designed to let a soldier carry a heavy pack over rough ground. Hydraulics can move heavy loads without difficulty, but the pumps and reservoirs are bulky and the fluid must be kept sealed. Most newer devices therefore use electric motors, which are quieter, cleaner and easier to control precisely.

The most developed market is medical. Several exoskeletons for people with spinal cord injuries have been approved by regulators: the ReWalk received clearance for personal use in the United States in 2014, and competing devices followed. They allow some users to stand, walk short distances and climb stairs, though most users still need walking aids, and they are used in rehabilitation to give patients repeated practice of a walking movement that therapists would otherwise have to provide by hand. The benefits are real but limited. Trials generally report gains in walking speed and in measures of independence rather than a return to normal walking, and participants must have enough strength in their arms and sufficient bone density to be considered suitable.

Industry is the other expanding area. Exoskeletons that support the arms are used where workers must hold tools above their heads, and frames that take the weight of a crouching posture have been tested by car manufacturers on assembly lines. The appeal is straightforward: a device that reduces the load on a worker's back or shoulders may reduce injury and fatigue, although few long-term studies of such claims have yet been published. In some factories workers wear an exoskeleton for part of a shift and take it off for the rest, so that the equipment does not become a burden in itself.

Several obstacles remain. Cost is the first: a device for use at home typically costs tens of thousands of dollars, and few health systems are willing to pay. Fitting takes time, because the frame must be adjusted to the individual's measurements. Most lower-limb devices require the user to hold crutches for balance and cope poorly with stairs or uneven ground. Pressure at the points where the frame meets the body can damage the skin, and batteries provide only a few hours of walking between charges. Nor is the evidence base yet strong: most studies are small, and they rarely follow users for more than a few months.

Research is therefore directed at making the machines lighter, cheaper and less demanding of the user. Soft exosuits, in which motors mounted at the waist pull cables that run down the leg, avoid the alignment problems of rigid frames and weigh far less; researchers at Harvard University's Wyss Institute have tested them with people recovering from stroke. Other groups are developing actuators that recycle energy rather than merely supplying it, and control systems that learn an individual's gait over repeated sessions, so that fewer sensors are needed. Exoskeletons for the hand and wrist are also being tried, although the many small joints of the hand make it a demanding target.

Information was once scarce and attention plentiful; the position is now reversed. The economist and psychologist Herbert Simon saw the change coming more than fifty years ago, observing that a wealth of information creates a poverty of attention, and that people would therefore have to allocate their attention carefully among the sources competing for it. What Simon could not foresee was the scale of the industry that would grow up around that competition, or the sophistication of the techniques it would use to win a share of it.

Most of the services that dominate the internet are free to use and are paid for by advertising. Their revenue depends on how many people look at an advertisement and for how long, so the firms that run them have every reason to keep users on the site. Growth in the number of users is reported alongside a second figure, the time each user spends, and that figure is treated as evidence of success. The consequence is a business in which the user's attention is the product being sold.

The methods used to hold it are not accidental. Designers of digital products have borrowed deliberately from behavioural psychology, and in particular from the study of gambling. A slot machine gives a reward unpredictably, and it is the unpredictability rather than the size of the reward that holds players at the machine; the anthropologist Natasha Dow Schüll, who spent years observing gamblers in Las Vegas, described the state they enter as the machine zone. Digital services reproduce the same structure. A notification may bring a message worth reading or nothing at all, and the uncertainty makes it harder for the user to leave the screen alone.

Other techniques are simpler. Endless scrolling, in which new material appears automatically as the user reaches the bottom of a page, removes the small decision that a page break used to require. Video services begin the next item without being asked. Counters record how many days in a row a user has returned. None of these is coercive in the sense that a law or a locked door is coercive; each merely makes one choice easier than another.

Evidence about the effects is often presented carelessly. It is true that many people report finding it hard to concentrate, and that interruptions are costly: research by Gloria Mark and her colleagues at the University of California, Irvine, has shown that office workers switch between tasks every few minutes, and that returning to an interrupted task takes time. It is also true that some claims go well beyond what research supports. Assertions that heavy use of social media has rewired the adolescent brain, or caused a measurable fall in intelligence, are not established findings; most studies in this field are correlational, and the direction of cause is disputed.

Defenders of the industry make three arguments that deserve a hearing. The first is that the services are voluntary, and that a user who dislikes them can close the account. The second is that attention has always been contested: newspapers fought for readers with sensational stories, and television was accused, in almost identical language, of addicting the young. The parallel with those earlier media is instructive, and it should make us cautious about declaring each new technology a unique danger. But it is also incomplete, because a newspaper could not adjust its front page to the known weaknesses of an individual reader, and television could not learn when a particular viewer was most likely to keep watching.

The third argument is that the benefits are genuine. Families separated by continents now speak daily; a student with an unusual interest can find others who share it; information that once took weeks to obtain arrives in seconds. These gains are real, and any serious criticism has to account for them. My objection is not that the technology is trivial or that its users are foolish. It is that the contest is unequal. On one side is an individual with limited willpower and a finite store of time; on the other are teams of engineers and psychologists whose task is to measure, and to defeat, exactly that willpower.

Framing the problem as a failure of individual discipline therefore misleads, though it is convenient for the firms concerned. When a design is deliberately built to be hard to resist, telling people to resist it is not a solution. The costs of a design decision taken in California are paid by millions of scattered individuals, none of whom can negotiate the terms. This is the classic case for collective rules rather than personal virtue, and regulation of this kind is not censorship. Requiring a company to report how long its users stay on a service would be one modest measure. Banning the collection of data about children for advertising would be another. Obliging platforms to switch off autoplay by default would be a third.

What I would resist is the assumption that nothing short of abandonment will do. The technology is not harmful in itself, and the attention it draws on is the ordinary human attention that teachers, friends and books have always competed for. What is new is the precision of the competition. Equally new is the asymmetry of information between the two sides: the company knows exactly how each user behaves, while the user knows almost nothing about how the company's systems work. A society that regulates the design of its digital streets, as it regulates the design of its physical ones, can keep the benefits without pretending that the costs do not exist.