IELTS Academic Reading Practice Test 22

Long before the rise of the Maya or the Aztecs, a sophisticated civilisation flourished along the humid, jungle-covered lowlands of what is now southern Mexico. The Olmecs, whose principal centres developed between approximately 1500 BCE and 400 BCE in the modern states of Veracruz and Tabasco, are widely regarded by scholars as the "mother culture" of later Mesoamerican societies. Their art, architecture, religion, calendrical systems, and writing all left traces that can be detected, transformed in various ways, in the practices of every subsequent civilisation in the region. Yet despite more than a century of investigation, the Olmecs generally remain one of the most enigmatic cultures of the ancient Americas, in part because the tropical climate has destroyed virtually all of their perishable material and because their hieroglyphic script, only recently recognised as a true writing system, has not been fully deciphered.

The first systematic archaeological work on Olmec sites began in the late nineteenth century with the writings of the Mexican explorer José María Melgar y Serrano, who in 1862 described a colossal stone head he had largely encountered near the village of Tres Zapotes. He believed the head, with its broad nose and full lips, depicted an African person and proposed an Atlantic crossing in remote antiquity — a hypothesis no longer accepted by mainstream scholarship. Serious excavation, however, did not commence until 1939, when American archaeologist Matthew Stirling, sponsored by the Smithsonian Institution and the National Geographic Society, undertook a systematic survey of Tres Zapotes, La Venta, and San Lorenzo. Stirling's work uncovered more colossal heads, intricate jade carvings, and a tradition of monumental construction that pushed the known horizons of Mesoamerican civilisation back by more than a thousand years.

The colossal heads typically remain the most visually striking achievement of Olmec sculpture. Seventeen examples have been documented to date, ranging in height from 1.47 metres to 3.4 metres and weighing between six and fifty tonnes. Each is carved from a single block of basalt quarried in the Tuxtla Mountains, more than 60 kilometres from the principal Olmec ceremonial centres. How the Olmecs transported these enormous blocks across rivers and jungles, without the use of wheels or draught animals, remains a subject of vigorous debate. The leading hypothesis holds that the blocks were floated downriver on rafts during the seasonal floods, then dragged along causeways constructed for the purpose. Each head wears a distinct helmet-like headpiece, leading most researchers to conclude that they represent specific rulers rather than gods.

The ceremonial centre of La Venta, occupied between roughly 900 and 400 BCE, provides the clearest picture of Olmec social organisation. At its heart stands the Great Pyramid, a 30-metre conical mound of clay that constitutes one of the earliest monumental structures in the Americas. Surrounding the pyramid are courtyards, drainage channels, and ceremonial deposits known as massive offerings, in which the Olmecs buried hundreds of tonnes of imported serpentine stone in geometric patterns. The labour required to construct La Venta, particularly to import the basalt and serpentine from distant quarries, implies the existence of a powerful elite capable of mobilising regional populations.

Trade and influence radiated outward from the Olmec heartland across distances of more than 1,500 kilometres. Distinctive Olmec-style figurines have been recovered from sites in Guatemala, Honduras, El Salvador, and central Mexico, and the chemical signatures of pottery clays demonstrate active long-distance exchange in obsidian, jadeite, and iron ore for use as polished mirrors. Researchers Kent Flannery and Joyce Marcus have argued, however, that Olmec influence beyond the heartland was more cultural than political: surrounding societies largely adopted Olmec iconography and ritual practices without ever falling under direct Olmec rule.

In recent decades, advances in remote sensing have transformed Olmec archaeology. Light Detection and Ranging, or lidar, allows researchers to map subsurface features beneath the dense vegetation of the Gulf Coast lowlands without the need for traditional excavation. In 2020, a team led by Takeshi Inomata of the University of Arizona used lidar to identify more than 460 rectangular earthen platforms in the region, most dating from between 1100 and 400 BCE, suggesting a far denser and more complex Olmec landscape than had previously been assumed. Inomata's team also documented evidence that the famous E Group astronomical alignments, long associated with the Maya, may have first appeared at the Olmec site of Aguada Fénix some five hundred years earlier than at any Maya centre.

The decline of the Olmec civilisation around 400 BCE is poorly understood. Many of the colossal heads at San Lorenzo and La Venta typically show signs of deliberate defacement, possibly indicating internal conflict, religious revolution, or invasion. Climate records derived from sediment cores in regional lakes reportedly indicate a period of severe drought beginning around 500 BCE, which may have undermined the agricultural base of the Olmec heartland. Whatever the cause, the cultural achievements of the Olmecs were absorbed and elaborated by the civilisations that succeeded them, ensuring that this little-known people exerted an influence on the ancient Americas wholly disproportionate to the modest territory they once controlled.

A The phenomenon of urban warming has been recognised for more than two hundred years. As early as 1818, the English amateur meteorologist Luke Howard, better known for his classification of cloud types, largely published a comparison of temperatures measured in central London and in the surrounding countryside. He found that the city's daily mean temperature was consistently higher, particularly at night and in winter, by an average of approximately 1.6 degrees Celsius. Howard called this excess heat the city's "artificial caloric." A century later, the German climatologist Wilhelm Schmidt formalised the term "urban heat island" to describe the same effect, which has since been documented in essentially every large city studied, on every inhabited continent.

B Several distinct mechanisms typically combine to produce an urban heat island. The first is the radiative behaviour of urban surfaces. Asphalt, concrete, brick, and dark roofing materials generally absorb a far higher proportion of incoming solar radiation than vegetation or bare soil, and they retain this heat well into the evening, releasing it slowly through the night. A typical asphalt road may reach surface temperatures of 60 degrees Celsius on a sunny day, compared with no more than 30 degrees Celsius for a grassed park nearby. The geometry of urban canyons — the deep, narrow spaces between tall buildings — apparently further traps thermal radiation, since heat radiated by one surface is repeatedly reabsorbed by adjacent walls before it can escape to the sky.

C A second contributor is the reduction in evaporative cooling. Vegetated and natural surfaces typically dissipate large amounts of solar energy as latent heat through the evaporation of soil moisture and the transpiration of plants. In dense urban areas, vegetation cover is reduced by more than two-thirds compared with rural surroundings, and rainwater is rapidly channelled into drains rather than absorbed by the ground. Consequently, a greater fraction of incoming solar energy is converted into sensible heat — heat that raises air temperature — rather than dissipated through evaporation. This contribution can account for as much as half of the total heat-island intensity in cities at temperate latitudes.

D Anthropogenic heat — the heat produced directly by human activities such as transport, industry, heating, and cooling — adds a third layer to the phenomenon. The density of energy use in city centres is staggering: a study of Tokyo's central business district by climatologist Kanda Manabu in 2007 measured an average anthropogenic heat flux of 200 watts per square metre during winter weekdays, exceeding the solar radiation reaching the ground at the same latitude. Air-conditioning units paradoxically intensify the effect by ejecting indoor heat into the surrounding outdoor air, raising local temperatures and prompting further air-conditioning use, in what climatologists describe as a positive feedback loop.

E The health consequences of urban heat islands have become increasingly well documented. The 2003 European heatwave, in which temperatures in Paris remained above 35 degrees Celsius for nine consecutive days, is widely thought to have caused an estimated 70,000 excess deaths across the continent, with city dwellers far more likely to perish than residents of rural areas. Particularly vulnerable groups generally include the elderly, those with cardiovascular or respiratory illnesses, and people living in poorly ventilated upper-floor apartments. Researchers at the London School of Hygiene and Tropical Medicine have estimated that heat-related mortality in major European capitals could double by the 2050s under unmitigated climate change, with the urban heat-island contribution accounting for around a third of the projected increase.

F Economic and ecological effects typically extend well beyond direct mortality. Higher urban temperatures generally increase residential and commercial cooling demand, raising electricity consumption and reinforcing dependence on fossil-fuelled generation. They also reportedly accelerate the formation of ground-level ozone and other photochemical pollutants, which compound respiratory disease. Ecologically, urban heat islands shift the timing of seasonal events: trees in central Tokyo bloom up to two weeks earlier than those in surrounding districts, and migratory birds apparently increasingly use cities as winter refuges, with potentially destabilising consequences for largely established food webs and disease cycles.

G Mitigation strategies broadly fall into three categories. The first involves changing surface properties: cool roofing materials typically reflect a far greater proportion of incoming solar radiation than conventional bituminous surfaces, with potential reductions in roof surface temperatures of more than 20 degrees Celsius. The Greek city of Athens has retrofitted thousands of buildings with light-coloured reflective coatings since 2015 and reports a measurable decrease in summer peak temperatures. The second category centres on increasing urban vegetation. Singapore's Garden City programme, initiated in the late 1960s, requires that new buildings replace ground-level greenery lost to construction with equivalent area on rooftops, terraces, and façades; recent measurements apparently indicate that this policy has reduced the city's urban heat-island intensity by an average of 0.7 degrees Celsius. The third category involves redesigning urban form to enhance natural ventilation, for example by aligning major streets with prevailing summer winds, as Stuttgart in Germany has done. Together, these strategies generally indicate that the urban heat-island effect, although difficult to eliminate entirely, can be substantially moderated through deliberate planning.

A The proposition that the language a person speaks influences how they perceive and reason about the world has fascinated thinkers since classical antiquity. In the twentieth century, however, the idea was given its most influential modern formulation by two American scholars, Edward Sapir and Benjamin Lee Whorf. Sapir, a brilliant student of the anthropologist Franz Boas, argued in the 1920s that languages do not merely express thought but actively shape the categories through which speakers experience reality. Whorf, an insurance investigator and amateur linguist who studied under Sapir at Yale, developed this idea further by drawing on his extensive fieldwork among the Hopi of Arizona. Together their writings gave rise to what later became known, somewhat misleadingly, as the Sapir-Whorf hypothesis — a label neither scholar ever used.

B For several decades after Whorf's untimely death in 1941, linguistic relativity was accepted as a guiding principle of cultural anthropology. The most famous claim, that the Hopi possessed no linguistic means of expressing time as a sequence of past, present, and future moments, became a staple of undergraduate teaching. Whorf argued that this absence corresponded to a fundamentally different temporal experience in Hopi culture, one in which the Western metaphor of time as a river flowing from past to future simply did not apply. The implication was profound: speakers of different languages did not merely describe the same world differently but inhabited cognitively different worlds.

C From the 1950s onwards, however, the strong version of the hypothesis came under sustained attack. The American linguist Noam Chomsky proposed that all human languages share a deep underlying grammar, hardwired into the brain by evolution, and that surface differences between languages were superficial and could not significantly constrain thought. In 1969, anthropologists Brent Berlin and Paul Kay published a landmark cross-linguistic study of colour vocabulary, which found that languages tend to develop colour terms in a predictable hierarchical sequence and that speakers of languages with fewer colour terms could nevertheless perceive the same colour distinctions as speakers of more elaborate systems. Whorf's specific claims about Hopi were also reassessed: the linguist Ekkehart Malotki demonstrated in 1983 that Hopi did, in fact, possess a rich vocabulary for time and tense, though it differed in structure from that of European languages. Together these critiques drove a generation of linguists to dismiss linguistic relativity as discredited.

D The pendulum began to swing back during the 1990s, as a new generation of researchers developed more rigorous experimental methods. Instead of relying on grand cultural generalisations, they focused on narrow, testable predictions: does the grammatical structure of a particular language correlate, in a measurable way, with how its speakers perform on specific cognitive tasks? The psychologist Lera Boroditsky, then at Stanford, played a pivotal role in this revival. In a series of widely cited studies, she demonstrated, for example, that Mandarin speakers, whose language often describes time vertically, are quicker to respond to up-down spatial primes when asked about temporal sequences than English speakers, whose language describes time horizontally.

E One of the most compelling lines of evidence concerns spatial cognition. The Aboriginal language Guugu Yimithirr, spoken in northern Queensland, expresses location only in absolute cardinal terms, equivalent to "north," "south," "east," and "west," rather than relative terms such as "left" or "right." Speakers must therefore know which way they are facing at all times. Experimental work by the linguist Stephen Levinson of the Max Planck Institute has shown that Guugu Yimithirr speakers maintain remarkable spatial awareness even in unfamiliar environments and indoors. They have been observed pointing accurately to distant cities they have not visited for years, and arranging objects on a table in the same absolute orientation regardless of which direction they themselves are facing. Speakers of relative languages, asked to perform the same tasks, generally behave quite differently.

F Grammatical gender provides another suggestive domain. In a 2002 study, Boroditsky and her colleagues asked German and Spanish speakers to describe nouns whose grammatical gender differed between the two languages — for example, "bridge," which is feminine in German but masculine in Spanish. German speakers used adjectives such as elegant, fragile, and slender, while Spanish speakers chose words such as sturdy, big, and dangerous. The pattern reversed for nouns of the opposite gender. Although the effect is modest, it appears consistently across many noun pairs and many bilingual experiments, suggesting that the grammatical gender of a noun subtly conditions how speakers conceptualise the object it denotes.

G Critics generally caution against overstating the implications of this work. They point out that all reported effects are quantitative shifts in performance rather than qualitative differences in cognitive capacity, and that speakers of any language can learn to make any conceptual distinction if motivated to do so. The English speaker can perfectly well learn to think of bridges as feminine, and the Hopi child raised in an American school has no difficulty mastering the calendar. The contemporary view, sometimes called neo-Whorfianism, holds that language influences habitual patterns of thought rather than determining the limits of what can be thought.

H The practical implications of even a modest form of linguistic relativity are nevertheless generally considerable. Translation between languages becomes a far more delicate enterprise than the simple substitution of equivalent words, since the categories of one language may carve experience differently from those of another. Education research suggests that bilingual children may develop a degree of cognitive flexibility precisely because they have access to multiple linguistic framings of the same situation. And ongoing language loss — by some estimates, half of the world's roughly 7,000 languages will cease to be spoken by the end of the century — implies the loss not merely of vocabulary and grammar but of the distinctive perspectives on reality that those languages embody. From this point of view, the work begun by Sapir and Whorf has lost none of its urgency, even if its more sweeping claims have been substantially revised.