IELTSwithJurabek

PASSAGE 2

Read the text and answer questions 14-26

Why don't we sleep?

A
Fifty-six million prescriptions for sleeping medication were handed out by doctors in America last year. Yet remarkably little is being done to understand insomnia's root causes. Socially and economically, the undertreatment of sleeplessness is hugely expensive. The Institute of Medicine, an independent scientific advisory group, estimates nearly 20 percent of all major accidents on the road are associated with driver sleepiness. The loss in terms of productivity within the workplace is even higher, costing billions. Then there are the softer costs which remain unmeasured but still exist; for example, the damaged relationships with others. If other medical problems were causing such widespread harm, governments would act, but US authorities contribute only about $230 million a year for the funding of sleep research, comparable to the amount that the manufacturers of popular sleeping pills spent in three months on advertising. Currently most medical school students get no more than four hours of training on sleep disorders; some get none.

B
If we don't know why we can't sleep, it's in part because we don't really know why we need to sleep in the first place. We know that we divide it between periods of deep-wave sleep and rapid eye movement (REM) sleep, when the brain is as active as when we're awake, but our voluntary muscles are paralyzed. We know that all mammals sleep, and that there are some insects and reptiles that only half sleep, in order to remain aware of their environment and predators.

C
The predominant theory of sleep is that the brain demands it. Recently, researchers at Harvard, led by Robert Stickgold, tested undergraduates on various aptitude tests, allowed them to nap, then tested them again. They found that those who had engaged in REM sleep subsequently performed better in pattern recognition tasks, such as grammar, while those who slept deeply were better at memorization.

D
Such studies suggest that memory consolidation may be one function of sleep. Giulio Tononi, a sleep researcher at the University of Wisconsin, published an interesting twist on this theory a few years ago. His study showed that the sleeping brain seems to delete redundant or unnecessary synapses or connections. So the purpose of sleep may be to help us remember what's important, by letting us forget what's not.

E
Sleep is likely to have physiological purposes too. Some researchers have found that sleep deprivation impedes wound healing in rats, and others have suggested that sleep helps boost the immune system and control infection. But these studies are not conclusive. At Stanford University, William Dement, co-founder of the Stanford Sleep Medicine Center, explains what he knows after 50 years of research, about the reason we sleep. 'As far as I know,' he said, 'the only reason we need to sleep that is really, really solid is because we get sleepy.'

F
The Stanford clinic does more than 3,000 overnight sleep studies a year. Their main diagnostic tool is the polysomnogram, the main element of which is the electroencephalograph (EEG), which captures the electrical output from a patient's brain. As the EEG records a person's sleep patterns, the polysomnogram technicians also measure body temperature, muscle activity, eye movement, and breathing. Then they look over the data for signs of abnormal sleep. When a person has narcolepsy, for instance, they plunge from wakefulness into REM sleep without any intermediate steps. However, Clete Kushida, the clinic director, told me he can spot most people's sleep problems right at the intake interview. 'There are those who cannot keep their eyes open, and those who just speak of their exhaustion but don't actually fall asleep. The former often have sleep apnea where they stop breathing. The latter have true insomnia.'

G
In sleep apnea, muscle relaxation allows the soft tissue of the throat to close, shutting off the sleeper's air passage. When the brain realizes it is not getting oxygen, it sends a signal to the body to wake up. The sleeper awakes, inhales, and sleep returns. Apnea is a serious problem but only indirectly a sleep disease. True insomniacs are people who either can't get to, or can't stay asleep for any evident reason.

H
While apnea can be treated with a device that forces air down the sleeper's throat to keep the airways open, the treatment of classic insomnia is not so clear cut. Acupuncture may help. It has long had this role in Asian medicine and is being studied at the University of Pittsburgh sleep center now. Typically in the US, insomnia is treated in two ways. First come the sleeping pills. Though safer than they once were, they can still lead to psychological addiction. 'Many users complain that their sleeping-pill sleep seems different, and they feel unfocussed on waking. Sleeping pills are not a natural way to sleep,' points out Charles Czeisler, director of the Harvard Health and Safety Group.

I
The second step in treating insomniacs is usually cognitive behavioral therapy (CBT). In CBT, a psychologist teaches insomniacs to think about sleep problems as manageable, and to practice good 'sleep hygiene': sleep in a dark room, go to bed only when you are sleepy, don't exercise beforehand. Studies have shown that CBT is more effective than sleeping pills at treating long-term insomnia, but many sufferers aren't convinced. 'Some people continue in my experience to struggle,' says John Winkelman, another sleep center director. 'They're not super-satisfied with their sleep.'

PASSAGE 3

Read the text and answer questions 27-40

Understanding symbols

Judy DeLoache describes her research into the difficulties children experience with symbols.

A.
About 20 years ago I had one of those wonderful moments when research takes an unexpected but fruitful turn. I had been studying toddler memory and was beginning a new experiment with two-and-a-half- and three-year-olds. For the project, I had built a model of a room that was in my laboratory. The real space contained basic furniture such as a couch and table. The miniature version was as similar as possible to its larger counterpart: the furniture was the same shape and material and was arranged in the same position. For the study, a child watched as we hid a miniature toy - a plastic dog we called Little Snoopy* - in the model. We then encouraged the child to find 'Big Snoopy', a large version of the toy, hiding in the same place in his big room.

B.
The three-year-olds were very successful. After they observed the small toy being placed behind the miniature couch, they ran into the room and found the large toy behind the real couch. But the two-and-a-half-year-olds failed abysmally. They cheerfully ran into the room to retrieve the large toy, but most had no idea where to look, even though they remembered where the tiny toy was hidden in the miniature room and could readily find it there.

C.
Their failure to use what they knew about the model to draw an inference about the real room indicated that they did not appreciate the relation between the model and the room. I realised my memory study was instead a study of symbolic understanding and that the children's failure might be telling us something about how and when children acquire the ability to understand that one object stands for another.

D.
The first type of symbolic object that infants and young children master is the picture. No symbols seem simpler to adults, but infants initially find pictures perplexing. The problem stems from the duality inherent in all symbolic objects: they are real in themselves and also representations of something else. A few years ago I became intrigued by anecdotes suggesting that infants do not appreciate this duality - stories of a baby trying to pick up a depicted toy or fit a foot into a photograph of a shoe. We assumed such behaviour would be rare and therefore difficult to study.

E.
Fortunately we were wrong. We began testing infants' understanding of pictures by putting a book of highly realistic colour photographs of individual objects in front of nine-month-olds. To our surprise, every child in the study reached out to feel or scratch the pictures. The confusion seems to be conceptual not perceptual. Infants can perfectly well perceive the difference between objects and pictures and given the choice they will choose the real thing. But they do not yet fully understand what pictures are and how they differ from real objects. However, when depicted objects bear little resemblance to the real thing - as in a black and white drawing - infants rarely explore them. By 18 months, babies have come to appreciate that a picture merely represents an object; instead of manipulating the paper, they point to pictures and name objects. Nevertheless, it takes several years for the nature of pictures to be completely understood.

F.
Studies have shown that, until the age of four, many children think that turning a picture of a bowl of popcorn upside down will result in the depicted popcorn falling out of the bowl.

G.
Pictures are not the only source of confusion for very young children. In a third experiment, we brought a group of toddlers (18- to 30-month-old children) into a room containing a child's slide, a chair, and a toddler-sized car. The children played with these for a while. Then we secretly replaced each object with an identical miniature version. Most children attempted to perform the same actions with the miniature items that they had with the larger ones. Some tried to sit on the chair, others attempted to climb into the car. Interestingly, most of the children showed little or no reaction to their failed attempts. We think this probably reflects the fact that toddlers' daily lives are full of unsuccessful attempts to do one thing or another. This confusion has implications for educational practice. Teachers everywhere use blocks or other objects to represent numerical quantity. However, if young children do not understand the relation between an object and what it represents, this could be counterproductive. To demonstrate this, we taught six- and seven-year-olds a difficult subtraction problem using blocks.

H.
We taught an identical comparison group the same concept, but using pencil and paper. Both groups learned to solve the problems equally well, but the group using blocks took three times as long to do so.

I.
Dual representation also comes into play in many children's books. Modern children's books are often 3D, with features that encourage children to interact directly with the book itself, for example flaps that can be lifted to reveal pictures. Graduate student Cynthia Chong and I reasoned that these features might distract children from the information. Accordingly, we used different types of books to teach letters to 30-month-old children. One was a simple old-fashioned alphabet book with each letter accompanied by an appropriate picture. The other was a 3-D version. The children using the traditional book subsequently recognised more letters than those using the 3-D book.

J.
Presumably, the children could concentrate more easily with the plain 2-D book, whereas with the other one they were distracted by the 3-D activities. Less may be more when it comes to educational books for young children.