Major high street restaurant chains are signing up to a background music service which plays music and subliminally encourages customers to buy nearly 10pc more food and drinks than they would usually.
A major study carried out in 16 branches of McDonalds in Sweden found the bespoke "brand-fit" playlists caused customers to increase spending more than 9pc.
Food giants including McDonalds, TGI Fridays and Wagamama are adopting the Spotify-backed service "Soundtrack Your Brand", which generates playlists for businesses which are tailored to their brand andspecially generated to put customers in a money-spending mood.
The study, conducted in a popular American restaurant, found music that was selected by the service, which uses an algorithm to choose music that suits restaurants' brand, made customers more likely to buy additional items than if the restaurant played random popular music.
Sales of desserts and sides, as an example, rose by more than 11pc, while sales of smoothies and shakes increased by 15pc, it found.
The test was carried out by the Swedish Trade Federation, which represents Swedish businesses, also found that playing no music at all was better than playing random popular music, with random music cutting sales by more than 4pc compared with silence.
Last year Marks and Spencer decided to switch off background music in stores for the first time in a decade after customers complained about the noise.
The new music-free policy was thought to be designed to please Marks and Spencer's ageing customer base, as experts said elderly people with hearing problems and dementia can find background music disorientating and make shopping less enjoyable.
However this latest research suggests that being irritated by background music is a problem which spans the generations.
Professor Sven-Olov Daunfeldt, who led the study, said: “When done right, music has a major positive effect on sales, largely stemming from guests purchasing more items such as desserts and sides. Play the wrong music, and you just might find that you’re alienating that very same customer and selling significantly less.”
He added that the "perfect playlist" should compromise a mixture of well-known and lesser known hits with a mixture of what's popular within the restaurant's theme.
The findings follow a separate study by Oxford University which found that traditional music, often played by curry restaurants to set the mood for diners, may also be making their food taste hotter.
Scientists say that certain types of music - those with fast beats, distorted notes and high-pitched sounds - can enhance the sensation of heat from chilli peppers. In a series of tests researchers were able to produce specific soundtracks that can boost the spiciness of food by up to 10 per cent.
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