The weapon was initiated at precisely 10:30 in the morning.

It was 23 June 1940 and World War Two was in full swing. The Germans had already invaded vast swathes of continental Europe; in the preceding weeks, 10,000 British troops had been captured in Normandy.

Now the BBC had been asked to get involved. Their powerful intervention was completely invisible, yet capable of infiltrating the minds of thousands of people all at once, all over the country. Over the next few years, it arguably helped to win the war.

This was the “Music While You Work” programme – a brainchild of the UK government, which thought that broadcasting live, upbeat music in factories twice a day might help to step up the pace of work and get the military the munitions they so badly needed.

It was a hit. In a report on the show’s success, BBC executives cited the numerous letters and reports they had received from managers nationwide. One described its impact as “incalculable”, while another estimated that, for an hour or so after a session of music, output at their factory increased by 12.5-15%.

Fast-forward eight decades and working to music is extraordinarily common; one 2019 survey of 2,000 Britons found that around half regularly listen to music while they work – with two out of five believing that it helps them to get more done. And as headphones have become standard work accessoriesand productivity playlists have racked up millions of views on YouTube, some companies have started to broadcast music over entire workplaces. 

Michael Vettraino, who founded the London-based music consultancy MAV music, says the company has helped to introduce background music to several offices. While their main focus is on providing bespoke playlists for restaurants, casinos and hotels, recently they have branched out into supplying offices, many of which are introducing music for the first time.

 “Our clients have told us that it's increased their productivity when they’ve had the right music playing in the office, in terms of staff motivation,” says Alex Hill, who works as MAV’s head of music and operations. They are always careful to factor in the demographics of their audience – their age, etc. – and fit the music to how they’re likely to be feeling at different times of day.

“When you're concentrating you’ll want calmer, more relaxing music and at the end of the day when you’re feeling tired, you’ll want something more upbeat. We know that a graphic design agency in Shoreditch is going to want very different music to a high street bank Gloucester. But if you get it right, it should hopefully help people to work harder.”

But can this really be true – or is it wishful thinking? It’s a perennial debate and one that’s almost as divisive as whether reclining your seats on an airplane is OK or what colour that notorious dress is.

The ‘Mozart effect’

Some of us feel that blasting out tunes in the workplace is an inalienable right; the teenager inside us swears they can’t concentrate without the dulcet tones of Kanye West or Taylor Swift ringing in their ears. One despairing worker took to social sharing site Reddit to vent about a colleague who gets into the zone each morning by playing mariachi band music.

Others take cocooning their brains from distraction extremely seriously, booking conference rooms for parties of one, constructing passive-aggressive emails about noise in the office and donning headphones while secretly listening to nothing. The billionaire Bill Gates reportedly gave up music and television at any time of day for five years in his 20s to help him focus.

“Historically, music and work have always been intertwined,” says Karen Landay, a former professional violinist and graduate student at the University of Alabama who has authored a review on the subject. “Think about romantic visions of peasants singing as they harvest, or sea chanteys sung by sailors as they work on their ships. And since most people enjoy listening to music of some kind in at least some contexts, it’s perfectly natural to feel that music must have some sort of positive impact on our work.”

There are two possible ways that music might be beneficial in the workplace: by making us smarter, or by making us feel good, and therefore helping us to plod on with otherwise boring tasks.

The best-known example of the first is the “Mozart effect” – broadly the idea that listening to a piano sonata devised by a genius can make you one too. The phrase was popularised after a 1993 paper claimed that people perform better on certain spatial tasks, such as folding paper, after listening to Mozart for 10 minutes.

The concept has spawned a whole industry of products, such as headphones that mothers can use to play Mozart to their unborn children. It sounds farfetched, but more recent studies have hinted that there might genuinely be something unusually beneficial about his music.

For example, research conducted in 2015 compared the impact of Mozart’s “K. 448”, a composition for two pianos, with Beethoven’s equally celebrated “Für Elise”, a solo piano piece. It turns out that while Mozart’s sonata increased “alpha band” brain waves – which have been linked to memory, cognition and problem solving – Beethoven, oddly, had no such power.

There’s also the discovery that mice who were subjected to 10-hour recitals of Mozart’s K. 448 for 10 weeks were significantly better at navigating a complex maze than ones which had to listen to Beethoven’s Für Elise instead.

So, with some famous composers’ work having clearer cognitive benefits than others – what are we to believe? There is another explanation, in which it doesn’t improve our intellectual abilities at all – it just seems to. This is where the second theory comes in.

Altering our mood

“Activation theory” was thought up in the 1960s, amid concern that people may struggle to remain productive in dull jobs, such as assembly line work in factories, for long periods of time. It’s broadly the idea that people need a certain amount of mental arousal in order to be able to function effectively.

“Depending on the individual, this can improve performance because it will increase attention,” says Landay. “However, if the level of activation becomes too high, performance could go down – imagine an overstimulated toddler.”

Some scientists think this is why certain music seems to be beneficial; it’s like a caffeine shot to the brain. For example, a 2001 study tested whether listening to the rather upbeat Mozart’s K. 448 or a slow, sad song – Adagio in G minor by Albinoni – could improve the spatial performance of a group of students. This time, they were also asked to rate their level of arousal before and after the task.

As usual, Mozart’s K. 448 was beneficial, while the other song did nothing to improve the participants’ abilities. Intriguingly, his piece seemed to alter their mood and increase their level of arousal, while Albinoni’s Adagio actually decreased it – and when the researchers factored this in, the Mozart effect disappeared.

This could potentially also explain why Beethoven’s Für Elise wasn’t as beneficial to the mice in the maze, and why it didn’t seem to activate any brain areas which are beneficial for cognition. For reasons that remain unclear, Mozart’s sonata might be better at altering our mood and boosting our levels of arousal, therefore improving our performance. There’s every possibility that Kanye West and Taylor Swift could be equally stimulating, but alas, no one has checked yet.

The finding also fits with research into how music affects our performance outside the lab. According to one 2019 review of the evidence, there has been very little objective, scientific research into how music affects our ability to work – and in those few studies that do exist, it doesn’t seem to be affecting our productivity directly.

For example, one 1995 study found that when workers at a large retail organisation were allowed to listen to personal stereos for four weeks, their performance improved significantly – entering more accounts per hour, for example – in comparison to a group of workers who were given no such privilege.

However, if the music was providing a direct cognitive boost, you would expect the type they listened to and the length of time they spent listening to be important. But this wasn’t the case – their performance improved equally, regardless of how many hours they spent with their stereo or whether they played Mozart or Eminem.

The researchers looked for links with a range of other factors, such as their job satisfaction. But in the end, the only factor that explained the improvements in productivity in the music group was how relaxed they felt. The researchers concluded that this was responsible for the surge, and not the music per se.

The enjoyment factor might also explain why, in a multitude of experiments conducted over nearly a century, many employees have consistently claimed that music improves their productivity – and their employers have confidently agreed with them. But when you actually measure this objectively, the evidence that music helps us to work is extremely murky.

Skewed perception?

In fact, some scientists think that music doesn’t really help us at all. Instead, it’s possible that we view the ability to listen to music as a gift from our employers, so we convince ourselves that we are working harder in return (though this might not actually be the case). It’s been suggested that this is why employees can react badly to having music taken away – these workers feel that they have already upheld their side of the bargain, and resent having the reward snatched from them.

And as we all know intuitively, in some contexts – such as during particularly complex tasks – music is actively detrimental. This is especially true for tasks which place more of a burden on our working memories, such as problem solving, and music which is less predictable or familiar, and therefore more cognitively demanding, like jazz.

There hasn’t been much research on this in the workplace, but one study found that the reading-comprehension and maths scores of undergraduate students were significantly worse when they completed them to music. It was especially harmful for those whose working memories weren’t as good to begin with.

The data suggests that we might benefit from this knowledge. One survey of 4,500 people by the online recruitment agency totaljobsfound that computer programming, data analytics, advertising and marketing – all of which are cognitively demanding – were the four sectors most likely to allow their employees to listen to music.

Our skewed perception of the benefits of music can even have life-threatening consequences. While some research has found that music can help surgeons stay calm and focused, a recent study found that it can make it hard for them to communicate basic instructions. By analysing hospital footage of 20 operations, the researchers calculated that surgeons were five times more likely to have to repeat requests when music was playing – and noted that this extra work can extend the length of operations by more than a minute.

Avoid arguments

So is music beneficial in the workplace?

One meta-analysis from 2011 concluded that background music “disturbs the reading process, has some small detrimental effects on memory, but has a positive impact on emotional reactions and improves achievements in sports”. This might explain why the BBC found that their wartime music programme improved productivity, because building munitions was tedious manual labour rather than intellectually challenging work. It also suggests that music might not be actively helpful in the office – it just makes us feel good.

According to Landay, we still have a long way to go before we truly know the answer. But at the moment, her best guess is that “it depends”. “A person’s response to music changes based on many, many factors, such as the type of job or work, the genre of music, their control over their music listening and their personality.”

Landay explains that there’s no one-size-fits-all recipe, so people should see what feels right for them. “Work environments where individual listening is not possible – such as call centres, retail or services – pose a larger dilemma,” she says.

Hill has a final word of advice. If you are going to broadcast music across a workplace, it’s essential to have a playlist made by someone else. “One of my friends asked me to send him a recommended playlist on Spotify because there's always arguments about who chooses the music in the office. Otherwise you get the rock guy one day and the rap guy the next and they'll hate each other.”