READING PASSAGE 2

Read the text and answer questions 14-26.

The Power of Smell

Research shows that our olfactory sense is more influential than we realise

A Dog noses are renowned for sensitivity to smells, while human noses are thought to be poor by comparison, yet that might be a misconception. According to recent studies, our noses are in fact acutely sensitive instruments that guide our everyday life to a surprising extent. Subtle smells can change your mood, behaviour and the choices you make, often without you realising it. Our own odours meanwhile, indicate emotional states such as fear or sadness to those around us. The big mystery is why we aren't more aware of our nasal activity. Noses have certainly never been at the forefront of sensory research, and were pushed aside until recently in favour of the seemingly more vital senses of vision and hearing. 'There has been a lot of prejudice that people are not that influenced by olfactory stimuli, especially compared to other mammals,' says Lilianne Mulica-parodi, who studies the neurobiology of human stress at Stony Brook University in New York, in the United States.

B One of the first people to assert the relative unimportance of human smelling was Pierre Paul Broca, an influential 19th-century anatomist. After comparing the proportion of the brain devoted to smell in different animals, he suggested that mammals can be classed into two broad groups: microsmatic mammals, such as dogs, have a finely tuned sense of smell which they rely on to perceive the world, while we, along with other primates and the marine mammals, are microsmatic – we have small olfactory organs that we only rely on to a small extent. That idea seemed to fit with more recent studies which found that the majority of mammals have genes coding for about 1000 different types of smell receptor. Most of these genes aren't expressed in humans, giving our noses just 400 different types of receptor.

C Yet these findings may have been misleading. Brain scans now show that more of the brain is devoted to smell processing than Broca's anatomical studies suggested. And although we may have fewer types of receptor than other mammals, Charles Greer at Yale University in the United States has shown that the human nose and brain are unusually well connected, with each group of receptors linking to many more neural regions than is the case in other animals. That should give us a good ability to process incoming scents. Once researchers began looking, they found the nose to be far more sensitive than its reputation suggested. One study, for example, found that we can detect certain chemicals diluted in water to less than one part per billion. That means that a person can detect just a few drops of a strong smell like ethyl mercaptan in an Olympic-sized pool.

D 'We are also exceptionally gifted at telling smells apart, even in the case of two molecules whose only difference is that their structures are mirror images of one another. That is fantastic sensitivity', says George Dodd, a perfumer and researcher at the olfaction group of the University of Warwick, in the United Kingdom. What's more, it's becoming clear that the brain’s olfactory centres are intimately linked to its limbic system, which is involved in emotion, fear and memory. That suggests a link between smell and the way we think.

E The power of smell will be no news to estate agents, who often advocate the smell of baking bread or brewing coffee to promote the sale of a house. But there are more subtle and surprising effects too. When Hendrick Schifferstein and colleagues, from Delft University of Technology in the Netherlands, pumped the smell of orange, seawater of peppermint into a nightclub, the revellers danced more, rated their night as more enjoyable, and even thought the music was better than when there was no added scent. Meanwhile, Rob Holland, of the University of Utechin the Netherlands, found that the hint of aroma wafting out of a hidden bucket of citrus-scented cleaner was enough to persuade students in a hostel to clean up after themselves.

F Other work has found that scent can influence our cognitive skills. A study by William Overman and colleagues at the University of North Carolina in the United States found that when men were subjected to a novel smell – either good or bad – during a task used to test decision-making skills, they performed significantly worse than normal. The researchers conclude the scent stimulated brain areas connected with emotion, making their decisions emotional rather than rational.

G Smells are especially good memory evokes, but it is actually a myth that odours trigger more detailed memories than other stimuli. 'The memory is not more accurate and you don't remember more details,' says Yaara Yeshurun at the Weizmann Institute of Science in Rehovot, Israel, 'but it is unique in that it is more emotional.' This isn't surprising when you consider that there are certain brain areas dedicated to both emotion and olfaction, such as the amygdala. and there is a strong link between emotion and memory. In 2009, Yeshurun found that the link between a memory and a smell is stronger if the smell is unpleasant rather than pleasant. She also discovered that the very first time we attach a smell to an object, it evokes a much greater response in our brains than for any subsequent encounter with the smell or object, laying down stronger foundations for the memory. That doesn't happen with any other sense. Since those first encounters with a smell would have happened at a young age, this explains why smells often transport us back to our childhood.

READING PASSAGE 3

Read the text and answer questions 27-40.

The costs of brand loyalty

A Londoner with a sudden urge for giant African snails could do worse than head to the bustling marketplace in Brixton, a part of south London that is home to many people from Africa. Markets like Brixton market that eater to migrants are testament to the fact that people often retain very strong preferences for the kinds of food they grew up eating. Just ask the expatriate Britons who flock to ‘Tea and Sympathy’ in New York's Greenwich Village for pots of Marmite, a yeast- based spread whose delights baffle other nationalities (and many of their own compatriots).

Past research has shown that people are often willing to pay much more for a favoured brand than for seemingly identical alternatives. It is not always obvious why. However, there is ample evidence to support the theory that certain food preferences form in childhood. Children have a predisposition to fear new foods, which is only overcome when they are repeatedly presented with, and encouraged to consume, a particular food. Evidence shows that children's instinctive wariness of new foods dates back to the times when humans had to forage for food, and it was important that they learnt which foods were safe to eat. In the modern world, people routinely express a strong liking for a brand even though they are unable to tell the brand apart from rival brands in blind tests, and many studies have found that advertising alone cannot explain the strength of brand loyalty.

A new study by economists from the universities of Tilburg and Chicago tracks the consumption patterns of 38,000 US households over two years, and confirms the theory that such brand loyalty is widespread, deep and long-lasting. There were clear local patterns in consumption, although the same brands were available everywhere. But 16% of people studied were migrants: they had grown up in one state and moved to another. These migrants had the same options, in terms of what was on offer and at what price, as everyone else in their adopted home, but although they consumed local favourites they bought fewer than longtime residents. {[This gap between purchases of migrants and those of the locally born was quite stubborn: although it faded the longer a person lived in their new state. it still took 20 year to halve in magnitude.][30]} {[Even 50 years on, it was still large enough to show up in the data.][36]} {[{[This could mean that the benefits of being the first brand into a market could last longer than might he assume][39]}d.][33]}

David Atkin of Yale University has identified some important implications of local food favourites. He suggests in a recent paper that the effects of people being loyal to known brands may also lead economists to rethink the say they calculate the benefits resulting from trade. This is because opening up to trade is in some ways very similar to migrating, as it changes the composition and prices of the foods that are available to a person. In particular, trade can cause local foods to become relatively more expensive. Atkin's data show something many economists do not take into account: when a traditional food has to compete with imported foods it may no longer be the cheapest food available for people to choose to eat. Atkin decided to look at this situation in the context of developing countries.

To illustrate his point, Atkin uses detailed data about people's food choices in India. India is a good choice because it covers a large number of climatic zones where different specialised crops are grown. Despite being part of the same country, the prevalence or internal barriers to trade means that its regions are best thought of as being only partially open to trade. Atkin's data show that the foods a region specialises in producing are instead cheaper in that region.

However, there has been some opening up of internal trade in India in recent years, and this has revealed that for every rupee spent on food, people's intake of calories declined most in regions where prices in local favourite foods had risen. In theory, when there is a greater choice of types of food, people should adjust their food habits and purchase the cheapest option so that they boost their calorie intake. However, in practice, food habits mean that consumers keep buying the things they know and like even though these foods have become relatively expensive. Atkin calculates that if all barriers to internal trade in India were abolished, the average Indian household would have to generate a rise of 3.3 percent in income to maintain their calorie intake.

In developing countries where there is a high prevalence of undernutrition, such as in sub-Saharan Africa, the habit of continuing to eat favourite foods could have a serious effect on development. There is clear evidence that nutritional shortfalls in children can affect their ability to work and earn as adults, and also has detrimental effects on their long-term health.

Consequently, the nutritional declines that can occur as a result of the opening up of trade are of serious concern, because an entire generation that is malnourished as children will continue to suffer irreversible consequences for the rest of their lives, which could hinder the development of their country due to a lack of a quality workforce.