Background music can influence what consumers buy and how much they are willing to pay for it, Australian musicologist Adrian North says.
Professor North has spent his professional life studying the psychology of music and how people interact with it in different spaces.
He said it was surprising, at least in Australia, that supermarkets were not tweaking their playlists to get people to spend their money in different ways.
Ever found yourself picking up some nice French mustard or cheese when Edith Piaf is playing over the speakers of your local supermarket or deli? You're not alone.
One recent study in a German supermarket found that French wine outsold German wine five bottles to one when French music was being played - but the German wine outsold the French when German music was being played.
North said French wine was on one shelf, the German on another although that was changed from time to time to reduce any shopper bias due to position.
A music player on the top shelf of the wine display then played either stereotypically French music such as La Marseillaise on an accordion or stereotypically German music such as an oompah band playing some beer drinking songs.
North said the surveyors pretended to be shoppers but they were really counting the bottles of wine sold.
"What we found is that when we played our French music then French wine outsold German by five bottles to one, where as when we played German music then German wine outsold French by two bottles to one.
"So the overall effect averaged out at about three and a third bottles of wine in favour of whichever country's music was playing."
North said typically shops play music to "create a nice ambience" which means they often just pick music that the customer demographic would typically listen to anyway.
But he said that may be a "missed opportunity" for some stores given some of the psychological evidence about what effect music can have in public spaces.
For example, another survey in a student cafeteria found that it was not necessarily the music that customers liked best that encouraged them to be prepared to spend more.
North said the survey took place over several weeks when different types of music were played which had been selected to create a different type of ambience.
"So on some days we played classical music, some days we played you know kind of Top 40 chart music, some days we played really stereotypical background music, you know easy listening if you like and then we had a control condition, some days we played no music."
The cafe patrons were then surveyed and asked about the cafe's ambience.
North said the results were unsurprising with people perceiving the cafe to be upmarket and sophisticated when classical music was playing and lively and youthful when pop music was playing.
Respondents were also asked what would be the maximum amount they would be prepared to pay for 14 different products that were on sale.
North said the results here were surprising and found that people were prepared to pay quite different amounts for products depending on what type of music was playing.
"The winner if you like was classical music, so this was done in the UK, we found that people would be prepared to pay 17.23 on those items when classical music was playing, where as the amount started to drop off when you placed other types of music."
North said this was despite the fact that they knew from the questionnaire that students did not typically like classical music that much. He said presumably they were prepared to spend more because the classical music was creating an upmarket ambience.
North said this does not necessarily mean that people will always be prepared to spend more if classical music is playing.
"I think probably the real lesson to take from findings like that is different [musical] genres have got all kinds of different stereotypes, different kinds of connotations for particular groups of people."
North said retailers should not base their musical decisions only on what they think their customers know and like.
"To instead thinking about what is it that they like and which creates the kind of atmosphere that's going to add something to the premises."
North said music is likely to sway people's spending decisions to a greater degree on smaller items.
He expected that music would have a relatively small effect for expensive purchases since customers are more likely to think about their decision to buy in much greater detail.
Classical not always the best retailer's option
North said it is not always classical music that encourages people to spend more, rather it can be about mapping music onto a product in a way that says something about the product.
For example, another survey found that people were more willing to spend more on utilitarian products such as hammer or bag of nails when country music was playing, rather than when classical music was.
"It's tapping into these connotations of country music as being you know if you like the music of the people, in some way it's practical, it's being outdoors."
Fast or slow?
Fast music leads to people going around supermarkets more quickly, while research has shown slow music encourages them to move around stores more slowly, North said.
"But because they're going more slowly they browse more and they actually spend more money."
North said that means that if the supermarket is busy it might be worth proprietors playing fast music to get people moving quickly, but if it is quiet it would be worth playing slow music to get customers to stay longer in the hope they will browse and spend more.
Research from the 1980s done in restaurants showed that diners took about a quarter of an hour longer to eat their dinner if slow rather than fast music was playing, but that also meant the slower diners spent more money at the bar, North said.
Music on hold
Even though music is increasingly available with streaming, businesses are still using a one size fits all approach, North said.
Businesses rarely ask their customers what they want to listen to when they are put on hold on the phone and that is a missed opportunity, North said.
"It's still so rare to come across a business that gives you the choice - you know if you're going to be sat there for 20 minutes, what would you like to listen to? You know would it be nothing or would it be musical genre A, musical genre B or something else altogether?"
North said research they did on why on hold music has the effect that it does had some surprising results.
The research advertised for people to be paid to take part in a survey but when they called they were put on hold, he said.
"What we did was when people called us we put them on hold automatically, and what we actually did was wait to see how long it would take for them to lose patience and hang up."
The respondents were later called back and interviewed.
North said the researchers thought people would stay on the line if they were listening to music that they liked and they used The Beatles as the base line for something almost everyone likes.
"What we found was that that wasn't very good at getting people to wait, it didn't work, even though we did subsequently find out that our callers did indeed like music by The Beatles most - it didn't make them stick around.
"What encouraged our callers to stick around and wait for longer was when we actually played, wait for it, pan pipe cover versions of those Beatles songs."
People said although the preferred the original Beatles songs they waited longer while the pan pipe versions were playing because it was calmer, North said.
North said that indicates that the function of on line call music is to keep you calm and try to distract you from the fact you are on hold.