Want to figure out if someone is a psychopath? Ask them what their favourite song is. A New York University study last year found that people who loved Eminem’s Lose Yourself and Justin Bieber’s What Do You Mean? were more likely to score highly on the psychopathy scale than people who were into Dire Straits.

Now obviously that study is very far from conclusive and no reason to cut Beliebers and Eminem stans from your life.

Nevertheless, you can tell a fair bit about someone by their music consumption.

Spotify certainly thinks so anyway. Someone who works at the company recently informed me that: “Nothing says more about someone than the music they listen.”

I have no idea if that’s a company-wide mantra, but it’s certainly ingrained in the streaming service’s business model.

Over the past few years, Spotify has been ramping up its data analytic capabilities in a bid to help marketers target consumers with adverts tailored to the mood they’re in. They deduce this from the sort of music you’re listening to, coupled with where and when you’re listening to it, along with third-party data that might be available.

Now, to be clear, there’s nothing particularly machiavellian about what Spotify is doing with your data.

I certainly don’t think that they are working with shadowy consulting firms to serve you ads promoting a culture war while you’re listening to music that suggests you might be in a casually racist mood.

Nevertheless, I find it depressing that our personal, private moments with music are increasingly being turned into data points and sold to advertisers. Or, in some cases, being mined for economic insights by central bankers. This year, the chief economist at the Bank of England said researchers were increasingly gauging the public mood by analysing Spotify streaming data.

I managed to overcome my feelings of moroseness about the monetisation of our souls (listening to Justin Bieber is very uplifting), however, and do some gauging of the public’s musical mood myself.

Miserable cities

I asked Spotify to crunch through some playlists for me and find the most miserable cities in the UK.

You may or may not be surprised to learn that Oxford and Cambridge listen to the most depressing music in Britain, while St Helens, in Merseyside, and Barnsley have the happiest listening habits.

But please don’t get distracted by my fun facts about Barnsley. I think it’s important that we end this piece feeling angry. You see, Spotify is far from the only platform helping brands target people according to their emotions; real-time mood-based marketing is a growing trend and one we all ought to be cognisant of.

In 2016, eBay launched a mood marketing tool, for example. And last year, Facebook told advertisers that it could identify when teenagers felt “insecure” and “worthless” or needed “a confidence boost”. This was just a few years after Facebook faced a backlash for running experiments to see if it could manipulate the mood of its users.

You can see where this could go, can’t you? As ad targeting gets ever more sophisticated, marketers will have the ability to target our emotions in potentially exploitative ways. According to one study, titled Misery Is Not Miserly, you are more likely to spend more on a product if you’re feeling sad.

You can imagine some companies might take advantage of that. And on that note, I’m feeling a little down about all this. Heading off to treat myself to something expensive.

–Guardian News & Media Ltd