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If you're already tired of hearing "Jingle Bells" while at the mall, there's a good reason.

Christmas music can be mentally draining, according to a clinical psychologist.

"People working in the shops at Christmas have to [tune out] Christmas music, because if they don't, it really does stop you from being able to focus on anything else," Linda Blair told Sky News. "You're simply spending all of your energy trying not to hear what you're hearing."

The so-called "Christmas Creep," wherein stores put out holiday decorations and products and play holiday music earlier each year, means that by mid-November, people are being driven bananas by all the forced holiday cheer. (And you can imagine what it does for those millions of people who don't celebrate the holiday.)

This ​​​​psychological reaction, notes NBC News, is known as the "mere exposure effect," according to music psychology researcher Dr. Victoria Williamson, who conducts research on the psychology of music at Goldsmiths, University of London.

According to Williamson, there's a U-shaped relationship between the amount of times we hear music that we like and our reaction to it. The first few times you hear your favourite Christmas songs you actually do feel festive, but once you hear those same tunes too many times, it becomes maddening.

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"Anyone who has worked in a Christmas store over the holidays will know what I'm talking about," Williamson told NBC News. But this reaction can depend on our psychological states, she noted, as some people like, or can tolerate, the bombardment of Christmas music, while other people feel like they're "going crazy."

For the latter folks, we don't have any good news for you because Christmas music — in stores, at least — is here to stay. And this is because it encourages customers to buy things.

Research has shown that the right balance of Christmas scents and songs can make shoppers feel more positive about their current environment, which makes them want to shop more.

"We've shown that 'holiday appropriate' music combined with congruent 'holiday scents' can influence shoppers by increasing the amount of time they spend in a store, their intention to revisit it, and intention to purchase," noted Eric Spangenberg, PhD, Dean of the College of Business at Washington State University.

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In a 2012 interview with HuffPost, music therapist Jennifer Buchanan noted that music can actually make people feel good about themselves, which may explain why some people shop more when they hear festive music.

"Music quickly taps into our rewards centres in our brain," she said. "What happens is for most of us in seconds, we will release hormones into our system, like dopamine, which will help us feel good."