Travellers arriving at Heathrow airport this year have been met by the smell of freshly-cu

t grass, pumped from a discreet corner via an "aroma box", a machine which blows warm, scented air into the environment. It can scent the area of an average high street shop with the smell of the chocolate, freshly-cut grass, or sea breezes, in fact any synthetic odours that can be made to smell like the real thing.

Heathrow's move into "sensory" marketing is the latest in a long line of attempts by businesses to use sensory psychology -- the scientific study of the effects of the senses on our behaviour to help sell products. Marketing people call this "atmospherics" -- using sounds or smells to manipulate consumer behaviour. On Valentine's Day two years ago the chain of chemist's Superdog scented one of its London shops with chocolate. The smell of chocolate is supposed to have the effect of reducing concentration and making customers relax. "Chocolate is associated with love", said a marketing spokeswoman, "we thought it would get people in the mood for romance." She did not reveal, though, whether the smell actually made people spend more money.

However, research into customer satisfaction with certain scented products has clearly shown that smell does have a commercial effect, though of course it must be an appropriate smell. In a survey, customers considered a lemon-scented detergent more effective than another scented with coconut despite the fact that the detergent used in both was identical. On the other hand, a coconut-scented suntan lotion was rated more effective than a lemon-scented one. A research group from Washington University reported that the smell of mint or orange sprayed in a store resulted in customers rating the store as more modern and more pleasant for shopping than other stores without the smell. Customers also rated the goods on sale as better, and expressed a stronger intention to visit the store again in the future.

Music too has long been used in supermarkets for marketing purposes. Supermarkets are aware, for example, that slow music causes customers to stay longer in the shop (and hopefully buy more things). At Leicester University psychologists have found that a specific kind of music can influence consumer behaviour. In a supermarket French wine sold at the rate of 76% compared to 20% German wine when French accordion music was played. The same thing happened in reverse when German bierkeller music was played In one American study people even bought more expensive wines when classical music was played instead of country music.

Writers and poets have often described the powerful effects of smell on our emotions, and smell is often considered to be the sense most likely to evoke emotion- filled memories. Research suggests however that this is a myth and that a photograph or a voice is just as likely to evoke a memory as a smell. Perhaps the reason for this myth is because smells, as opposed to sights and sounds, are very difficult to give a name to. The fact that smell is invisible, and thus somehow more mysterious, may partly explain its reputation as our most emotional sense.

What is the use of "aroma box" at Heathrow airport？

A．It can send a lot of synthetic fragrance into the environment.

B．It is a machine which blows warm and fresh air into the environment.

C．It often pumps the smell of freshly-cut grass from a high-street shop.

D．It is a box which sends out not only aroma but also music.