IELTS Academic Reading — Practice Test 9

For much of the twentieth century, raising a child with two languages was regarded as a handicap. Early studies, many of them poorly designed, reported that bilingual children scored worse on verbal tests than their monolingual peers, and educators warned parents that a second language at home would confuse the young mind and hold back learning. Immigrant families were frequently urged to abandon their mother tongue for the good of their children. From the 1960s onwards this consensus began to unravel. Researchers realised that the earlier studies had compared poor immigrant children with wealthier native speakers, so that social disadvantage, not language, explained the gap. Once such factors were controlled, the supposed deficit largely vanished, and attention turned instead to whether bilingualism might bring benefits.

By the turn of the century, a bolder claim had taken hold: that speaking two languages does not merely leave the mind unharmed but actively sharpens it. The focus fell on what psychologists call executive function — the set of mental skills used to plan, to hold attention, to switch between tasks and to ignore distractions. In a long series of experiments, the psychologist Ellen Bialystok and her colleagues found that bilingual participants, from young children to older adults, tended to outperform monolinguals on tasks requiring them to suppress an obvious but wrong response. A bilingual child asked to sort cards first by colour and then by shape, for instance, seemed to manage the switch more smoothly. Similar patterns turned up in adults asked to ignore the meaning of a word and respond only to the colour of its ink, a classic measure of mental control. The idea of a 'bilingual advantage' spread rapidly, reaching newspapers and parenting manuals as established fact, and for a decade it was treated as one of the more attractive findings in psychology.

The proposed explanation was elegant. When a bilingual person speaks, researchers argued, both languages are active at once; the brain cannot simply switch one off. To produce a sentence in one language, it must continually suppress the words and grammar of the other. This amounts to a lifetime of mental exercise in exactly the skill that executive function describes — selecting one option while inhibiting a competing one. On this account, the constant, unconscious management of two languages trains the brain's control systems much as physical exercise trains a muscle, and the benefit spills over into tasks that have nothing to do with language at all.

The most dramatic version of the claim concerned old age. If bilingualism strengthens the brain over decades, it might also protect it against decline. Studies of hospital patients reported that bilingual people developed the symptoms of dementia, on average, some four to five years later than monolinguals with the same underlying disease. The explanation offered was 'cognitive reserve': a lifetime of managing two languages was said to build up a buffer that allowed the brain to keep functioning despite the damage of illness. Crucially, the bilinguals were not spared the disease itself; their brains showed the same physical deterioration. They simply coped with it for longer before the effects became apparent.

Then came the reckoning. As other laboratories tried to reproduce the findings, many failed. Large studies with thousands of participants found no bilingual advantage in executive function, or found it only in some tasks and not others that supposedly measured the same skill. Sceptics pointed to a familiar pattern: studies that found an advantage were more likely to be published than those that did not, so the scientific record exaggerated the effect. Sample sizes in the influential early work had often been small, and small studies produce unstable results. One review of conference abstracts found that positive findings were far more likely to make it into print than null ones, leaving behind a distorted picture. When several teams pooled their data and analysed it together, the once-striking effect shrank almost to nothing. The bilingual advantage, critics concluded, might be largely an artefact of how the research had been reported.

The truth is probably neither the triumphant story of the 2000s nor its wholesale rejection. Bilingualism is not one thing: it ranges from a person who learned a second language at school and rarely uses it to someone who switches between two languages every hour of the day. Recent work suggests that any cognitive effects, where they exist, depend on how, when and how often the two languages are used, and may be too subtle to show up reliably in a simple laboratory task. The dementia findings, based on real clinical populations rather than brief laboratory games, have proved more durable than the executive-function claims, though they too remain contested and await larger, carefully matched samples. What is no longer in doubt is that bilingualism does no harm — the very fear with which the century began — and that, for tens of millions of families, it remains a source of opportunity rather than risk.

Pour enough water molecules together and something appears that no single molecule possesses: wetness. A lone molecule is neither wet nor dry; the property belongs only to the collection. The same pattern recurs at every scale of nature. A single ant, following a few crude rules, is close to helpless, yet a colony of them builds ventilated nests, farms fungus and wages war with a coordination that looks like intelligence. Individual neurons are simple switches, but a hundred billion of them, wired together, somehow give rise to thought. In each case a system displays features that none of its parts has on its own, and that could not easily be guessed from studying those parts in isolation. Philosophers and scientists call this phenomenon emergence, and it sits awkwardly with the way science has usually tried to explain the world.

That usual way is reduction: the strategy of understanding something by breaking it into its components and explaining the whole in terms of them. Reduction has been extraordinarily successful. Chemistry was grounded in the behaviour of atoms, heredity in the structure of molecules, and the assumption that a system is nothing more than the sum of its parts has driven much of modern science. Emergence appears to resist this strategy. If the properties of a whole cannot be read off from the properties of its parts, then knowing everything about the parts is not, after all, to know everything about the whole. To the reductionist this is unsettling, and much of the debate about emergence turns on whether it represents a real limit on reduction or merely a temporary gap in our knowledge.

Philosophers have found it useful to distinguish two versions of the idea. In its weaker form, emergence is a claim about practice. The behaviour of a complex system is hard to predict from its parts, but only because the calculation is too large or the interactions too tangled for us to follow; in principle, a sufficiently powerful computer, given the rules governing each part, could reproduce the whole. Traffic jams and weather systems are often described this way. The stronger form makes a far more radical assertion. Here the emergent properties are held to be genuinely new, not merely hard to compute but impossible in principle to derive from the parts, however complete our knowledge and however great our computing power. Which of these two, if either, actually occurs in nature is the heart of the dispute.

Defenders of strong emergence point to what they call downward causation. Ordinarily we imagine causation running upward, from the small to the large: atoms determine the behaviour of the cell, cells that of the organism. But in a complex system, they argue, the whole can constrain and direct its parts in ways the parts alone would never produce. The pattern of a whirlpool governs the motion of the water molecules caught within it; a living cell channels the chemistry of its molecules toward keeping itself alive. If the higher level can act back upon the lower in this way, then it is not a mere by-product of the parts but something with causal power of its own. To sceptics this sounds suspiciously like magic, a violation of the principle that the small ultimately governs the large.

Those sceptics offer a deflating alternative. Emergence, they contend, names not a feature of the world but a feature of us — our limited ability to calculate. When we say that a property 'could not have been predicted' from the parts, we are really confessing that we lacked the information or the computing power to do so. Give a sufficiently detailed model enough time, and the supposedly emergent behaviour would appear on schedule, fully explained by the interactions below. On this view there is no genuine novelty in nature, only complexity that outruns the human mind. The apparent gap between parts and wholes is epistemic — a matter of what we happen to know — rather than a real break in the fabric of causation.

Whichever interpretation is correct, the study of how complex order arises has become a science in its own right. A recurring finding is that elaborate global patterns can spring from simple local rules, with no central controller directing the outcome. A flock of starlings wheeling across the sky has no leader; each bird merely adjusts to its nearest neighbours, and the sweeping collective shape is the result. Markets set prices through millions of uncoordinated individual decisions. The immune system defends the body without any organ in charge of the campaign. Researchers call this self-organisation, and its ubiquity suggests that the production of order from the bottom up, without design or command, is one of nature's most general tendencies — whether or not it involves genuine novelty.

The question, then, is not whether emergent behaviour is real — flocks and colonies plainly exist — but how deep it goes. If the strong version holds, there are truths about the world that no amount of knowledge of the fundamental particles will ever yield, and the dream of a single theory that explains everything from the bottom up is an illusion. If the weak version holds, emergence is a challenge to our computing power rather than to our physics, and the reductionist programme remains intact in principle even where it fails in practice. Between these lies a great deal of unsettled ground, and the difficulty of designing any experiment to decide between them is itself a clue to how strange the phenomenon remains.