And what exactly is happening in the brain when you listen to music that you like? Well last month, published in the Journal Science, Valerie Salimpour and colleagues at McGill University Montreal imaged the brains of volunteers whilst playing them soundbites of music and found that perhaps unsurprisingly, when the participant rated that they liked a particular new tune then a bit of their brain called nucleus accumbens which is buried deep in the brain, lit up with activity. It's involved in reward during addiction, eating and sex.
The response of the nucleus accumbens that could predict whether the people were likely to buy that new piece of music that they haven't heard before, but scientists think that the individual's previous exposure to different environments and different musical scenes might affect those connections which then connect with the nucleus accumbens and drive the reward or pleasure response to the music.
So, we've learned a little bit about what happens when our brain reacts to music that we like, but what about, earworms? So, songs that you don't necessarily like! Why do particular songs get stuck in people's heads? I started by asking a few people what music plagues them.
Male - My current earworm is Tonight's the Kind of Night and that's by a band called Noah and the Whale. (Singing)"Tonight's the kind of night when everything could change" and I get this earworm when I'm driving or when I'm walking somewhere because it's quite a good pace for walking and I think as I'm walking, the song goes round and round in my head. (Singing) "Tonight's the kind of night when everything could change".
Male Two - Well, I actually have a different problem because there were these really cliché bits of music like Pachelbel's Canon that you hear all around the place. Whenever I hear it, for about a day afterwards, I just can't get it out of my head.
Female - The most annoying singer currently is Rihanna. I regularly have earworms about her songs. Every once in a while, you have a singer who don't like the tone of their voice, the content of the songs, and there's other ones that always stick with you.
Hannah - To find out about the science behind this phenomena, I spoke to Dr Lauren Stuart from Goldsmiths at the University of London who has been collecting thousands of reports from BBC 6 Music listeners. I started by asking what's the most common earworm?
Lauren - That's the question that we started to ask. Lady Gaga was coughing up quite a bit, but you might well say, well, that's probably because she had a lot of airtime.
Hannah - Yeah, she's being listened to a lot by the listeners and so, of course, it's going to be going around and round, and round.
Lauren - Exactly, but we were interested, are there any structural features of songs that are reported many times that distinguish those tunes. So, we want to say, what are the structural features that are left over, once you've accounted for recently and popularity? We're still in the process of refining a formula, but we can say that actually, many, many songs are reported as earworms. There's only a very small number that are reported a handful of times. So, it seems that the tunes in our heads are quite idiosyncratic.
Hannah - Everyone has their own individual earworm going on, yeah. At the moment, I've got the Beatles' "Here Comes the Sun" going round and round, round, which is lovely.
Lauren - Absolutely.
Hannah - Do you think there's any reason why we have these earworms?
Lauren - So, of all the questions that fascinates the general public in terms of music in the brain and the psychology of music, the question of why we have earworms and whether or not they have a purpose was one that really seem to pop up a lot and nobody was answering it. So, we thought we could try to at least have a go at doing so and it's harder than you might think to start addressing such question because it's a completely subjective phenomenon. All the studies that have been done on earworms have relied on people telling us, "Yeah, I have a tune in my head" but you know, that's very antithetical to how we normally measure things in science. We normally like to have something objective, some proof that there is something going on in the head. Some brain measurement or reaction time or accuracy measure, not just somebody saying, "Yeah, I've got Lady Gaga "Bad Romance" going on in my head". "Have you really? Should we trust you?" But one hypothesis that I'm particularly interested in looking at is whether or not earworms are a kind of unconscious form of self-regulation. So, by that time, I mean, in the same way when we actually choose real music to listen to from our iTunes library perhaps, we can be very deliberate and conscious about the type of music that we pick out to listen to. And it would be very context dependent. It will be very related to current mood, the mood that we would like to be in.
Hannah - Or maybe the people we're around?
Lauren - Yeah, exactly. The situation that you know, are we doing up some boring task at that time or are we doing the household chores, are we having a bath.
Hannah - And do you think that people consciously or subconsciously pick their earworms?
Lauren - Yes. That's exactly where I was going with this.
Hannah - So, I'm picking my "Here Comes the Sun" because the sun has arrived this weekend.
Lauren - Well, yeah. I mean, we have published a paper, looking at the various triggers that seem to precede earworms and there are many of them. The example that you gave, "Here Comes the Sun" is some kind of them in the lyrics has got resonance with some aspect of your environment or your life. But then there are many other triggers as well. So, there could be recent exposure to a particular song. When we have an earworm, it might be that our brain is unconsciously selecting for us a tune that matches our current mood state or perhaps more interestingly, a tune that matches our desired state of mind.
Hannah - So, if you're feeling down, you may pick an earworm that's quite nice and cheery and jolly because you want to be in the good mood?
Lauren - Exactly or for instance, I was getting ready to pick my son up from nursery and I started getting like a nursery rhyme in my head. Now, it's difficult to say whether or not because I'm thinking about him and that's something really closely related to him, or it could be it was serving the function of getting me in a very sort of energetic state of physical arousal.
Hannah - Getting prepared to pick up your son and spend time with him and be energetic?
Lauren - Just run around and play, yes.
Hannah - So, you were priming your mind in some way?
Lauren - Exactly. Some people say, but surely, there can't be any reason for it because you know, I have these really uncool songs. I get Bananarama or Mr. Blobby and that's surely not going to do me any good for my mood or whatever. So, to them, they think, "This is really just irritating." I think that it could be something that's specific to the tempo of these earworm songs that is serving the function of getting you to a particular energy level if you like. From your brain's perspective, it doesn't care about what's cool and what's not cool. It perhaps just selects a tune in the right tempo range to get you into that state. So, it's kind of complicated because it also depends on - you know, some people might have these earworms that are less prone to noticing them. In that case, you could say, well, maybe you don't have to consciously notice them for them to do their job of regulating your energy level. So, these are things that we probably have to think about and factor in as well.
Hannah - So, some people are possibly better at tuning out their earworm?
Lauren - It could be that, yeah. Just as we have to tune out like real music sometimes if we're in public places and there's music that's distracting us from what we're actually doing. So sometimes, yes. Perhaps that also is the case with internally generating music as well.
Hannah - That was Dr. Lauren Stuart from Goldsmiths at the University of London.