In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
Q: Article: Endless playing of songs like All I Want For Christmas in shops during the festive season doesn't just drive us mad--the songs also make us more careless with our money, research has warned. While repeated performance of Jingle Bells may seem like an innocent attempt to raise customers' spirits during the nightmare of Christmas shopping, the songs also have a more delicate impact.[:ZXXK] "Background music, or 'muzak', can be used by marketers to impose cultures--such as the commercialization of Christmas--onto consumers and influence their behaviour, "experts said. Dr. Alan Bradshaw of Royal Holloway, University of London, said, "Festive jingles are force-fed to Christmas shoppers in a bid to change their mood, influence their sense of time and what sort of products they buy. In other words, this is an attempt to control your shopping habits in a way that you might hardly be aware of." "Often we are told that we have the freedom to choose where we want to shop, but during Christmas the use of music in this way is so common that our freedom to choose disappears." Dr. Bradshaw and Prof Morris Holbrook of Columbia University examined the phenomenon and found that retailers often "dumb down" the music played in shops to relax customers, meaning it is easier to control their behaviour. It is thought that slowing down the rhythm of music in shops can trick customers into thinking less time has passed, and therefore spend more time examining the shelves, for example. Some providers of background music have been known to promote their services by claiming they can boost profits by controlling the behaviour of customers. "A common trick is to take a popular current song and record an instrumental version which can be slowed down or sped up at different time of the day to influence behaviour in different ways," Dr Bradshaw said. Background music is often classed as "Muzak" in honor of the Seattle-based company which began producing its soft-sounding melodies in the 1930s.
Answer: let customers spend more time shopping
A:
Shopkers slow down the rhythm of music in shops to _ .