Allergic babies

By Dr M. YADAV


Allergy is becoming an increasingly prevalent problem in many countries, especially among our young.

ALLERGIC diseases represent a major and increasing health problem in industrialised countries. Over the past five decades, the prevalence of allergic diseases has increased dramatically and the incidence has doubled in the last 20 years in most industrialised countries.

In some countries, for example Australia and Sweden, 40% of young children have allergic disorders.

In Malaysia, about 30% of young children are likely to develop allergic disorders in the first five years of life.

The most common allergic conditions in children and infants are food allergies, eczema, asthma and allergic rhinitis. Allergies are often life-long and although treatable, they tend to recur if the triggers are not strictly avoided. Some food allergies spontaneously improve within three years but are often replaced by respiratory allergies. Thus, it makes sense to try to prevent the development of allergies in early life than trying to treat them later.

Hence, there is great interest to identify the risk factors associated with the development of allergic disorders in early life and modify them to reduce subsequent risks for development of allergy.


Many studies show that breast milk decreases the incidence of allergic eczema compared to cow’s milk.

Risk factors for allergy

The development and appearance of allergic symptoms depends on poorly-understood complex interactions between genetic and environmental factors.

It is evident historically that changing environmental factors have played a major role for the increasing trends in allergy and asthma. Obviously, we have some control over the environmental risk factors but we have practically no control over genetic factors, which have an equal role in the development of allergic disorders.

Families often ask how allergy can be prevented in future offspring. The American Academy of Pediatrics published a clinical report in 2008 with recommendations for those infants at high risk of developing allergic disease. Avoidance of the major risk factors could reduce or prevent the development of allergic disease in most infants. For the avoidance measures to work, the first two years of life are critical and the measures must be applied before the development of allergy in the neonate.

These recommendations do not apply to babies already having food allergy. The major risk factors for the development of allergy in infancy are:

· Strong family history of allergic disease (both parents or one parent plus one sibling with allergy) may significantly increase the risk for allergy in the newborn.

· Exclusive breast feeding is desirable for least four months compared with feeding with intact cow’s milk. Many studies show that breast milk decreases the incidence of allergic eczema compared to cow’s milk.

Partially hydrolysed whey formula, which is hypoallergenic (reduced ability to stimulate and induce an IgE-mediated immune response) formula is preferred as supplementary feed for babies. The hypoallergenic formula is the preferred feed for the baby when the mother is unable to breastfeed. There is no role for soy-based formula in allergy prevention.

· Solid foods should not be introduced before ages four to six months. Early introduction of solid foods increases the risk, but delayed introduction of solid foods beyond six months provides no advantage.

· Exposure as a child or infant to high levels of house dust-mite allergens (allergens are substances, usually proteins, that cause allergy) increases risk to respiratory allergies. Anti-dust mite barrier encasing of mattress and pillows may provided some protection. Regular use of anti-dust mite sprays to reduce the level of dust mite allergens in the home environment is desirable. These procedures are specifically important for Malaysia, which has high dust-mite allergens levels in the home environment.

· Exposure to some indoor mammalian pets (e.g. cat) increases risk in the baby. Keep the pets strictly outside the house away from the baby’s play area and bedroom or remove the pets until the baby is older.

· No smoking should be permitted in the house during pregnancy and lactation. Passive exposure to cigarette smoke during pregnancy or infancy increases the risk for allergy significantly in early life.

· Passive exposures to cigarette smoke during pregnancy or infancy increases the risk for allergy significantly in early life.

· Exposure to environmental pollution as a child or infant (e.g. high levels of car exhaust fumes or fumes from gas heaters) increases the risk.

Maternal diet during pregnancy and lactation The earliest possible nutritional influence on allergy in the infant is the diet of the pregnant mother.

It is well known that food allergens in the diet of the mother can appear in the circulation and be transmitted to the amniotic fluid during pregnancy or breast milk during lactation. The foetus in late pregnancy (when the immune system is immature but functional) can be sensitised (develop the capacity to react to allergens on subsequent exposure) to the food allergens present in the amniotic fluid. In families with a genetic predisposition, there is a good chance that the newborn, when re-exposed to the provoking foods (e.g. cow’s milk), will react with symptoms (e.g. diarrhoea, vomiting, colic, eczema) to the sensitising foods. In families without a genetic allergic-background, the sensitised baby will not react to the provoking allergens.

Prior to 2008, the American Academy of Pediatrics had recommended avoidance of peanuts, cow’s milk, soy milk, fish and eggs during pregnancy and lactation to reduce the risk for allergy to these foods in the baby.



However, in January 2008, the American Academy of Pediatrics reversed their position on maternal avoidance of specific foods. The current position, based on evidence from large number of research studies, does not support maternal avoidance of allergenic foods during pregnancy or lactation. Moreover, maternal avoidance of specific nutrition during pregnancy may not be conducive for the healthy growth of the baby.

Low levels of maternal dietary food-allergens present in breast milk may cause allergic symptoms (e.g. eczema) in exclusively breastfed babies. Our studies in Malaysia show that exclusively breastfed babies with skin symptoms are mostly reactive to cow’s milk and egg white proteins. However, in some babies, additional allergens such as wheat, peanuts, soy bean, sesame seeds, banana, chicken meat, garlic and many others were also contributory to the development of allergic eczema. In all these babies, there was a family history of allergy.

The continued breastfeeding and maternal avoidance of the provoking foods is normally advised when the infant is less than four to six months. In older infants, breast milk can be stopped and the weaning diet should exclude the provoking foods.

In all such cases it is essential to identify the provoking food allergens through blood allergy tests on the baby based on the maternal diet. Any delay in seeking allergy services may potentially lead to adverse clinical outcome due to unacceptable diagnostic oversight.

Food allergy in Malaysian children Investigations into food allergy in Malaysia were pioneered by Dr N. Iyngkaran and his colleagues, including myself, in the mid-70s at the then University Hospital.

At that time, chronic diarrhoea in infants was a major cause of morbidity and mortality. In a series of experimental studies, it was demonstrated that cow’s milk was the primary cause of the chronic gastroenteritis diarrhoea in young infants. These infants suffered from symptoms of vomiting, diarrhoea and colic. Moreover, the associated lactose intolerance was recognised as secondary to the intestinal mucosal damage inflicted by the cow’s milk allergic reaction. This was an important contribution because for the first time the relationship between cow’s milk allergy, intestinal mucosal damage, lactose intolerance and clinical symptoms became clear. The group went on to demonstrate that many other proteins, such as egg protein and soy protein, which caused allergic reactions in young infants and children, were also responsible for marked intestinal mucosal aberrations.

One interesting study performed by the group showed that about 40% of infants with cow’s milk allergy developed allergic reaction to soy milk even if the baby had not been exposed to soy products previously. Only in recent years has it become clear that cow’s milk casein shares common allergens with soy protein and hence infants sensitised to casein will eventually react to soy if it is used as a substitute in infants allergic to cow’s milk.

Adverse reactions to cow’s milk are frequently seen in the first year of life in infants on bottle feed. Cow’s milk allergy is present in 3-5% of infants and 85% will outgrow the milk allergy by the third year.

However, in some children, particularly those with high titres of IgE antibody and severe symptoms, the milk allergy will persist longer, usually into adolescence and sometimes into adulthood.

The symptoms of cow’s milk allergy usually starts in the first weeks of life. The main symptoms of cow’s milk allergy are:

gastrointestinal in about half the infants; skin eczema in two-third of infants; and respiratory problems in about quarter of infants. In many infants, all three symptoms may be present.

Young children with eczema are at a higher risk of developing food allergy, particularly those infants and toddlers whose skin disease is more severe or recalcitrant to therapy. Generally, the younger the patient and the more severe the eczema, the more likely food allergy is a causative factor.

Parental perceptions with regards to food allergy in their children are notoriously inaccurate. Parents often have very strongly held beliefs that certain foods cause a variety of symptoms, many of which are inconsistent with an immune-mediated process.

In fact, when the diagnosis of IgE-mediated food allergy are performed in an established laboratory using approved allergy tests, only about 40% of patients’ histories of food-induced reactions can be verified. Thus it is very important to conduct an allergy test at a centre managed by professionals.

Food allergy in children is most likely to manifest between one and three years. In Malaysian infants less than one year old, the foods causing allergy in order of importance are cow’s milk, soy milk, chicken eggs and fish.

On the other hand, in children more than two years old, the foods causing allergy in order of importance are shellfish (prawns/shrimp), cow’s milk, chicken eggs, wheat, soy and peanuts. In 70% of children, chicken egg allergy lasts until the twelfth year.

Peanut allergy tends to be long-lasting, with 20% infants resolving by the ninth year, but in the rest, it may be life-long. Avoidance of the provoking foods is essential for success in treating food allergy.

The only objective method of measuring IgE antibodies is to use technology that is calibrated against established reference preparations. The CAP RAST blood test is scientifically considered superior to any other allergy test for the detection of the provoking allergen in the infant’s diet. It is a quantitative test with each run incorporating controls which are standardised against WHO standards. The blood allergy test is not affected by medications, including anti-histamines.

Elimination of the food allergen is the only proven effective therapy at this time. Strict dietary avoidance is generally recommended once a food allergy is diagnosed.

If the mother is breastfeeding, she must also strictly eliminate the causal foods from her diet. Clinical tolerance can develop over time, more commonly to some foods (milk, egg, soy, wheat) over others (peanut, tree nuts, seafood). In time, the baby will outgrow the allergy brought on by the provoking food (e.g. cow’s milk or chicken eggs) and show no food-specific IgE-antibody. Only then can the problematic food be successfully reintroduced into the diet of the child without worrying about the development of adverse reactions. In rare cases, some food (e.g. chicken egg, shrimp/prawn, bird’s nest soup) may cause severe systemic life-threatening reaction (called anaphylaxis) within minutes of ingestion of the provoking food. The symptoms appear rapidly, usually with minutes of exposure to the provoking food. The symptoms include: (1) skin or mucosal involvement (e.g. generalised hives or swelling of oral mucosa), (2) respiratory compromise (e.g. dyspnea, wheeze), (3) persistent gastrointestinal symptoms (e.g. vomiting), (4) hypotension (e.g. hypotonia, fainting).

Epinephrine, which is dispensed in special syringes called Epipen, is clearly the treatment of choice for anaphylaxis. Following epinephrine treatment, the individual should be rushed to the hospital.

Certainly, having signs of hypotension (even without accompanying symptoms) is an indication for epinephrine administration, particularly in a child with known food allergy. It is important to identify the provoking foods through food allergy tests if any one has had this experience of anaphylaxis since such episodes tend to reappear in reactive individuals. Avoiding the trigger resolves the problem.

Food allergy in infancy predicts respiratory allergy in mid-childhood.

Food allergy in infants less than one year old predicts the development of respiratory allergy and asthma in children five to eight years old.

There are ways for physicians to increase the predictive value of the allergy test. One factor is the level of specific IgE antibody in serum, which can affect the presence, persistence and severity of the allergic disease. Thus the risk of developing asthma increases with increasing specific antibody levels.

A sensitised infant with specific IgE antibody to food allergens (e.g. cow’s milk, chicken egg) and/or aeroallergens (e.g. cat dander, dust mite) summing up to a total of 0.5 kilounits per litre (kU/L) has 20% risk of developing persistent wheezing/asthma, but if the summed antibody level is greater than 10 kU/L in early life, the predictive value for wheezing/asthma increases to 90% at five years of age.

This definitely calls for quantification of IgE antibody levels if allergy is suspected in the young baby for assessing the severity of the disease. Allergy is not a simple yes or no phenomenon of allergy tests. Recent studies show that prediction and diagnosis of allergy needs to be based on several factors, including quantitative of IgE antibody levels.

Conclusion

In Malaysia, food allergies in infancy are increasing rapidly. In young infants, the most common foods causing allergies are cow’s milk and chicken eggs. The next commonest are soy milk, wheat, fish and peanuts.

In older children, shellfish (e.g. shrimp/prawns, crab), in addition to the other foods noted in infancy, is most important.

The majority of children with food allergy in the first year of life will develop respiratory allergy to house dust mites during mid-childhood. Thus, early measures to prevent the risk for development of allergy are desirable.

For further information, e-mail starhealth@thestar.com.my. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.

Memory pill that could help with exam revision could be available soon

A "memory pill" that could aid exam revision and help to prevent people forgetting important anniversaries may soon be available over the counter.

By Lucy Cockcroft


Memory-enhancing pills, created to treat Alzheimer's disease, could be redeveloped as a 'lifestyle pill' to combat memory loss and help exam revision.

The medicine has been designed originally to help treat Alzheimer's disease, but could be adapted and licensed for sale in a weaker form within the next few years.

One brand of memory-enhancing pill is being developed by the multinational company AstraZeneca in collaboration with Targacept, an American company, while Epix Pharmaceuticals, also from the US, is developing another.

Both have "cognitive-enhancing effects" which are aimed at treating patients with age-related memory loss.

Steven Ferris, a neurologist and former committee member of the Food and Drug Administration in the US, has predicted that a milder version will be available for healthy consumers as a "lifestyle pill" available over the counter.

Dr Ferris said: "My view is that one could gain approval, provided you showed the drugs to be effective and safe. It could be a huge market."

There is anecdotal evidence that mind-improving drugs are already being taken in Britain by healthy users.

Provigil, used to treat narcolepsy, is being taken by some students to help them stay awake, while Adderall XR and Ritalin, treatments for attention deficit disorder, are being used to help promote concentration.

A spokesman Adderall XR said: "We get a lot of calls from college campuses asking about it.

"There are risks though. It can raise blood pressure, people shouldn't do it."

The Department of Health said it was not illegal to buy the medicines over the internet, but it was not recommended.

Barbara Sahakian, professor of clinical neuropsychology at Cambridge, said: "It's hard to quantify the scale of the phenomenon but it's definitely catching on.

"The reality is we're not always at our best. After being up at night looking after the kids or travelling, many people would love to have something to sharpen them up. It's not taboo to drink Red Bull. The principle with cognition enhancers is not so different."

The way the brain buys

Retailers are making breakthroughs in understanding their customers’ minds. Here is what they know about you

IT MAY have occurred to you, during the course of a dismal trawl round a supermarket indistinguishable from every other supermarket you have ever been into, to wonder why they are all the same. The answer is more sinister than depressing. It is not because the companies that operate them lack imagination. It is because they are all versed in the science of persuading people to buy things—a science that, thanks to technological advances, is beginning to unlock the innermost secrets of the consumer’s mind.

In the Sainsbury’s in Hatch Warren, Basingstoke, south-west of London, it takes a while for the mind to get into a shopping mode. This is why the area immediately inside the entrance of a supermarket is known as the “decompression zone”. People need to slow down and take stock of the surroundings, even if they are regulars. In sales terms this area is a bit of a loss, so it tends to be used more for promotion. Even the multi-packs of beer piled up here are designed more to hint at bargains within than to be lugged round the aisles. Wal-Mart, the world’s biggest retailer, famously employs “greeters” at the entrance to its stores. Whether or not they boost sales, a friendly welcome is said to cut shoplifting. It is harder to steal from nice people.

Immediately to the left in Sainsbury’s is another familiar sight: a “chill zone” for browsing magazines, books and DVDs, tempting impromptu purchases and slowing customers down. But those on a serious mission will keep walking ahead—and the first thing they come to is the fresh fruit and vegetables section.

For shoppers, this makes no sense. Fruit and vegetables can be easily damaged, so they should be bought at the end, not the beginning, of a shopping trip. But psychology is at work here: selecting good wholesome fresh food is an uplifting way to start shopping, and it makes people feel less guilty about reaching for the stodgy stuff later on.

Shoppers already know that everyday items, like milk, are invariably placed towards the back of a store to provide more opportunity to tempt customers. This is why pharmacies are generally at the rear, even in “convenience” stores. But supermarkets know shoppers know this, so they use other tricks, like placing popular items halfway along a section so that people have to walk all along the aisle looking for them. The idea is to boost “dwell time”: the length of time people spend in a store.

Traditionally retailers measure “footfall”, as the number of people entering a store is known, but those numbers say nothing about where people go and how long they spend there. But nowadays, a ubiquitous piece of technology can fill the gap: the mobile phone. Path Intelligence, a British company working with the Massachusetts Institute of Technology, tracked people’s phones at Gunwharf Quays, a large retail and leisure centre in Portsmouth—not by monitoring calls, but by plotting the positions of handsets as they transmit automatically to cellular networks. It found that when dwell time rose 1% sales rose 1.3%.

Having walked to the end of the fruit and vegetable aisle, Basingstoke’s hard-core shoppers arrive at counters of prepared food, the fishmonger, the butcher and the deli. Then there is the in-store bakery, which can be smelt before it is seen. Even small supermarkets now use in-store bakeries. Mostly these bake pre-prepared items and frozen dough, and they have boomed even though central bakeries that deliver to a number of stores are much more efficient. They do it for the smell of freshly baked bread, which makes people hungry and thus encourages people to buy not just bread but also other food, including frozen stuff.

Most of the information that shoppers are bombarded with is visual: labels, price stickers and advertising. But the wafting bread aroma shows smell can usefully be stimulated too, says Simon Harrop, chief executive of BRAND sense agency, a British specialist in multi-sensory marketing. In the aisle by the laundry section he suggests introducing the smell of freshly laundered sheets. Even the sound of sheets being folded could be reproduced here and contained within the area using the latest audio technology. The Aroma Company, which Mr Harrop founded, has put the smell of coconut into the shops of Thompson, a British travel agent. Some suntan oils smell of coconut, so the scent is supposed to remind people of past holidays. The company even infuses the fresh smell of citrus into a range of clothing made by Odeur, a Swedish company. It can waft for up to 13 washes.

Such techniques are increasingly popular because of a deepening understanding about how shoppers make choices. People tell market researchers and “focus groups” that they make rational decisions about what to buy, considering things like price, selection or convenience. But subconscious forces, involving emotion and memories, are clearly also at work.

Scientists used to assume that emotion and rationality were opposed to each other, but Antonio Damasio, now professor of neuroscience at the University of Southern California, has found that people who lose the ability to perceive or experience emotions as the result of a brain injury find it hard or impossible to make any decisions at all. They can’t shop.

Oh, that’s what I want
Researchers are now exploring these mechanisms by observing the brain at work. One of the most promising techniques is functional magnetic resonance imaging (fMRI), which uses a large scanner to detect changes in the blood flow in parts of the brain that correspond to increases or decreases in mental activity. People lying inside the scanners are shown different products or brands and then asked questions about them. What they say is compared with what they are thinking by looking at cognitive or emotional activity. The idea is that if, say, a part of the brain that is associated with pleasure lights up, then the product could be a winner. This is immensely valuable information because eight out of ten new consumer products usually fail, despite test marketing on people who say they would buy the item—but whose subconscious may have been thinking something different.

“We are just at the frontier of the subconscious,” says Eric Spangenberg, dean of the College of Business at Washington State University and an expert on the subtleties of marketing. “We know it’s there, we know there are responses and we know it is significant.” But companies commissioning such studies keep the results secret for commercial reasons. This makes Dr Spangenberg sure of one thing: “What I think I know, they probably know way more.”

We are just at the frontier of the subconsciousRetailers and producers talk a lot about the “moment of truth”. This is not a philosophical notion, but the point when people standing in the aisle decide what to buy and reach to get it. The Basingstoke store illustrates some of the ways used to get shoppers’ hands to wobble in the direction of a particular product. At the instant coffee selection, for example, branded products from the big producers are arranged at eye-level while cheaper ones are lower down, along with the supermarket’s own-label products.

Often head offices will send out elaborate plans of where everything has to be placed; Albertsons, a big American supermarket chain, calls these a “plan-a-gram”. Spot-checks are carried out to make sure instructions are followed to the letter. The reason for this strictness is that big retailers demand “slotting fees” to put suppliers’ goods on their shelves, and these vary according to which positions are considered to be prime space.

But shelf-positioning is fiercely fought over, not just by those trying to sell goods, but also by those arguing over how best to manipulate shoppers. Never mind all the academic papers written on how best to stack shelves, retailers have their own views. While many stores reckon eye-level is the top spot, some think a little higher is better. Others charge more for goods placed on “end caps”—displays at the end of the aisles which they reckon to have the greatest visibility (although some experts say it all depends on the direction in which people gyrate around a store—and opinion on that is also divided). To be on the right-hand-side of an eye-level selection is often considered the very best place, because most people are right-handed and most people’s eyes drift rightwards. Some supermarkets reserve that for their own-label “premium” goods. And supermarkets may categorise things in different ways, so chapatis may not be with breads, but with ready-meals of the Indian variety. So, even though some suppliers could be paying around $50,000 per store a year for a few feet of shelf space, many customers still can’t find what they are looking for.

Technology is making the process of monitoring shopper behaviour easier—which is why the security cameras in a store may be doing a lot more than simply watching out for theft. Rajeev Sharma, of Pennsylvania State University, founded a company called VideoMining to automate the process. It uses image-recognition software to scan the pictures from security cameras of shoppers while they are making their selections. It is capable of looking at the actions of hundreds of thousands of people. It can measure how many went straight to one brand, the number that dithered and those that compared several, at the same time as sorting shoppers by age, gender and ethnicity.

VideoMining analysed people in convenience stores buying beer. Typically it would take them two minutes, with the majority going straight to one brand. “This shows their mind was already made up; they were on autopilot,” says Dr Sharma. So brewers should spend their marketing money outside, not inside, the store. The analysis can also help establish the return on investment to a new advertising campaign by showing what proportion of beer-buyers can be persuaded to consider rival brands. Another study in a supermarket some 12% of people spent 90 seconds looking at juices, studying the labels but not selecting any. In supermarket decision-making time, that is forever. This implies that shoppers are very interested in juices as a healthy alternative to carbonated drinks, but are not sure which to buy. So there is a lot of scope for persuasion.

Reducing the selection on offer might help too. Cassie Mogilner of Stanford University and her colleagues found in a study that consumers like unfamiliar products to be categorised—even if the categories are meaningless. In a study of different coffees they found people were more satisfied with their choice if it came from a categorised selection, although it did not matter if the categories were marked simply A, B and C, or “mild”, “dark roast” and “nutty”.

Despite all the new technology, simply talking to consumers remains one of the most effective ways to improve the “customer experience”. Scott Bearse, a retail expert with Deloitte Consulting in Boston, Massachusetts, has led projects observing and quizzing tens of thousands of customers about how they feel about shopping. It began when a client complained that he had mountains of data on the one in four people that entered his store and bought something, but knew hardly anything about the vast majority who left without making a purchase. The “customer conversion” rate varies between types of store: it could be around 20% in some department stores but reach almost 100% in a grocery. And within the same store the conversion rate will vary in different sections.

People say they leave shops empty-handed more often because they are “unable to decide” than because prices are too high, says Mr Bearse. Working out what turns customers off is not difficult, yet stores still struggle with these issues: goods out of stock, long queues at the checkouts and poor levels of service. Getting customers to try something is one of the best ways of getting them to buy, adds Mr Bearse. Deloitte found that customers using fitting rooms convert at a rate of 85% compared with 58% for those that do not do so.

Often a customer struggling to decide which of two items is best ends up not buying either. A third “decoy” item, which is not quite as good as the other two, can make the choice easier and more pleasurable, according to a new study using fMRI carried out by Akshay Rao, a professor of marketing at the University of Minnesota. Happier customers are more likely to buy. Dr Rao believes the deliberate use of irrelevant alternatives should work in selling all sorts of goods and services, from cable TV to holidays.

The notion of shoppers wearing brain-scanning hats would be ridiculousA lack of price tags is another turn-off, although getting that right will become crucial with the increasing use of Radio Frequency Identification (RFID) tags. These contain far more information than bar codes and can be scanned remotely. People have been predicting for years that they would shortly become ubiquitous; but, with costs continuing to fall, they eventually will. Tills will then become redundant, because everything shoppers put in their trolleys will be automatically detected and charged to their credit cards.

The basic mechanisms to do this are already in place. A store or loyalty card can be fitted with an RFID tag to identify customers on arrival. A device on the trolley could monitor everything placed in it, check with past spending patterns and nudge customers: “You have just passed the Oriels, which you usually buy here.”

Mind over matter
Technology will also begin to identify customers’ emotions. Dr Sharma’s software has the potential to analyse expressions, like smiles and grimaces, which are hard to fake. And although fMRI scanners presently need a crane to move, something that provides a similar result might one day be worn on your head. Researchers believe it is possible to correlate brain patterns with changes in electrical activity in the brain, which can be measured with electroencephalography (EEG) using electrodes placed on the scalp. Small EEG machines are already available, especially for computer gamers, which fit on the head.

The notion of shoppers wearing brain-scanning hats would be ridiculous if it were not so alarming. Privacy groups are already concerned about the rise of electronic surveillance that records what people do, let alone what they might be thinking. The San Francisco-based Electronic Frontier Foundation is concerned that because RFID tags can be read at a distance by anyone with the necessary equipment they could create “privacy pollution”; being used to discover what is in not only someone’s shopping trolley, but also their cupboards.

To some degree shoppers would have to “buy in” to the process: a bit like having an account with an online retailer which comes with the explicit knowledge that your past purchases and browsing history will be monitored and used to pitch purchase suggestions. And if that makes shopping easier—especially if sweetened with discounts—then consumers might sign up to it. When Dr Sharma asks shoppers what they think about his video-monitoring he says most people do not mind.

But what if psychological selling is done stealthily? That way lies grave perils. It is the anger not of privacy groups that retailers should fear, but of customers at being manipulated from behind the scenes.

There have been backlashes before: “The Hidden Persuaders” by Vance Packard, an American journalist, caused a sensation when it was first published in 1957 by revealing physiological techniques used by advertisers, including subliminal messages. It is what got Dr Spangenberg interested in the subject. He thinks shopping science has limits. “I don’t think you are going to be able to make someone buy a car or a computer that they don’t need,” he says. “But you might persuade them to choose one model instead of another. And importantly, they wouldn’t know it.” But if they did realise psychological methods were being used to influence their choice, “the counteraction can be so huge it can put someone off buying anything at all,” he adds.

Which is probably why at the end of this shopping trip there is not much in the trolley. At least the temptations at the checkout are easy to avoid: a few celebrity magazines and bags of sweets at the eye-level of children. But that will change too.

Barry Salzman, the chief executive of YCD Multimedia in New York, has big plans for the area around a cash till. He is using digital video screens displaying ads that relate to what someone is buying and which can also be linked with facial-recognition software to refine the displays according to the customer’s age or sex. His system is already being used in Aroma Espresso Bars in America to present, say, an advert for a chocolate croissant to someone buying only a cappuccino.

But the checkout in this Sainsbury’s comes to a halt because the teenager at the till is not old enough to sell alcohol and can’t attract the attention of a supervisor for permission to ring up a multi-pack of beer, which is therefore left behind on the counter. The science of shopping is a marvellously sophisticated business; the practice is still a little more primitive.

Opposite sex drives you crazy -- the causes

By Joy Hepp

(LifeWire) -- As Walter Christensen, a 53-year-old physics professor from Pomona, California, discovered, when it comes to cuddling, women know what they want. When he and his lover spend the night together, he's usually awoken around 3 a.m. with a familiar request.

"She calls out, 'Spoon, spoon!'" he says. He willingly obliges with front-to-back cuddling -- even though he admits he probably wouldn't do so without being asked.

"I like the feeling of her wanting to do that," he says, "so I do it out of a sense of responsibility."

His lover, 32-year-old art-history scholar Natalie Valle, appreciates the attention.

While the differences between the sexes drive some couples to distraction, being aware of them enhances relationships, as Christensen and Valle can attest. Is there hope for the rest of us? Researchers have found that science can be used to explain a lot of behavior that widens the gender gap, and in so doing may help couples understand each other better.

1. Women want to cuddle

What you think: Women love to cuddle after sex, whereas men just want to fall asleep.

What the experts say: "During sexual intercourse, oxytocin is released in both men and women, and that encourages bonding within the couple," says Dr. Marianne J. Legato, founder of the Partnership for Gender-Specific Medicine at Columbia University and author of "Why Men Never Remember and Women Never Forget."

Oxytocin is a hormone often associated with love because its levels increase during intimate acts like hugging, kissing and intercourse. However, "testosterone neutralizes the effect of oxytocin, so men are less likely to want to prolong contact after orgasm."

2. Men hate shopping

What you think: Men hate to go shopping with their mate because they think it's a waste of time.

What the experts say: Men do enjoy shopping when they get to "hunt" for a specific item, whereas women enjoy "grazing" for items. This goes back to our hunting and gathering days, when losing focus could mean losing the week's meal.

"Men are much more task-oriented," says Robert Schwarz, a psychologist and director of the Mars and Venus Counseling and Wellness Center in Haverford, Pennsylvania. "They hunt it, they kill it, they buy it and they go out."

In the aptly titled 2007 study "Men Buy, Women Shop," University of Pennsylvania researchers found that factors having to do with speed and convenience were the most important for men. Of the 1,250 male and female shoppers surveyed by phone, finding parking near the store or mall entrance was the No. 1 problem men said they encountered when shopping (29 percent of respondents), whereas women cited "lack of help" as their chief complaint (also 29 percent).

3. Women make mountains out of molehills

What you think: Women obsess about every little thing; men seem to have it all under control.

What the experts say: Men are problem-solvers and tend to bring up a problem only in order to search for its solution, says Schwarz. The "eureka" moment of problem-solving increases the level of dopamine, a pleasure-inducing chemical, in the brain. (This also explains why men will wait until it's absolutely necessary to stop and ask for directions.)

Women relieve stress by talking and relating their problems to others, which produces serotonin, said to enhance moods and ward off depression.

4. Men are impervious to cold

What you think: Men are content to freeze, while women always want to turn up the thermostat.

What the experts say: According to the Mayo Clinic, women are more sensitive to cold than men are, but not because they like to feel warm and cozy. Because women on average are smaller than men, their metabolic rate tends to be lower. This means their bodies generate less heat. They also tend to have less fat, which acts as insulation, on their upper bodies and around their waists, as well as less muscle mass, which also helps keep the body warm.

5. Women Love 'chick flicks'

What you think: Women prefer romantic movies (aka "chick flicks") while men like action and adventure. Watch how troops like chick flicks »

What the experts say: Women may like romantic movies better than men, but in a 2007 study at Kansas State University, men rated romantic movies "higher than most people would have guessed," says psychology professor Richard Harris, who led the survey of 265 Kansas State students. On a scale of 1 to 7, men gave the movies a 4.8, while women rated them a 6.

However, "we found that when seeing the film on a date ... if one party makes the decision, then they stay true to those stereotypes, with guys choosing to go to a violent film and women choosing a romantic film," Harris told the Reuters news agency in January.

Jose Ferraro can relate. He spent New Year's Day at the theater, dozing through the romantic drama "Atonement" with his wife, Kyle.

"She tricked me into going," says the 44-year-old engineer from Yorba Linda, California.

His wife, Kyle, a 49-year-old fitness instructor, fesses up: "I said there was some fighting in it," she admits.