Yesterday, I wrote a post on earworms and delved deep into some ideas as to why we get them.

But there is not solid answer to date and I expressed several research-based thoughts:

• Earworms are an involuntary auditory image

• 30-40% of our conscious thoughts are involuntary, and auditory images appear to be the most dominant of the phenomenon

• Involuntary imagery in general is substantially more common in people with a vocal stutter, usually relating to negative experiences in their childhood.

• There's a recipe to maximize the likelihood of earworms. Typically, it's things like the chorus of a pop song, jingles, TV commercials, video games, children's songs and Christmas songs.

• The Zeigarnik effect demonstrates that the incompleteness of a song or phrase puts our mind in a state of tension, keeping a pathway to that 'task' open until we have scratched the brain itch, similar to a waiter who prioritizes current orders while quickly forgetting complete ones.

• Earworms are potentially a remnant of ancient history before we discovered writing; passing down information would have been done by repeatedly looping information in our heads via song and dance.

Brain Itch

I want to go back a little to that Zeigarnik Effect (And Lewin's Field Theory). This idea of incompleteness seems substantial to me. It's a very psychological phenomenon, and in that way, not in your ears at all. Let me explain.

In your brain, the auditory cortext is the centre of music, and it can become activated either by listening to music or simply imagining or recalling the music.

Researchers at Dartmouth University found that playing part of a familiar song and then stopping it triggered the same areas in the auditory cortex as it did when listening to the whole song; your brain automatically tries to finish the song for you, with or without playback, and this can be physically seen:

This doesn't happen with unfamiliar songs, since your brain has nothing to ancitipate - unless it's a very predictable, Ed Sheeran piece of junk.

Basically, your brain treats the unfinished feeling like a mosquito bite, and just like a mosquito bite, the more you scratch it, the worse it gets. This can be quite debilitating for some people with 5.5% of people in studies saying that it can be significantly distracting, causing them to waste a lot of time.

Increased Prevalence

Now I haven't checked research on this - I imagine it would be very difficult - but with the invention of recording technology, we have set ourselves up to feed each other with earworms on an hourly basis.

We are constantly bombarded with incomplete music; stopping off at the coffee shop, walking through the mall, skipping through your playlists or hearing something in the background of a YouTube video. Our attention-economy lifestyle exposes us to more incomplete snippets of audio than ever before, actively exacerbating the global earworm phenomenon.

But what if you go deaf?

Musical Hallucinations

Tim Griffiths, a researcher in Newcastle took this earworms a step further. He selected a group of people who claimed to have musical hallucinations and scanned their brains when they said they actually heard music, even though there was none.

When comparing to the brains of regular individuals actually listening to real music, he found that the results of both groups were identical. He couldn't tell the difference between the two scans if he tried.

This separates musical hallucinations from earworms; these patients are actually hearing real music, as if you were standing at a rock concert.

So what was going on here? Actual, measurable music in the brain playing over and over? How?

This is the most fascinating part for me. The process of auditory imagination seems to happen in reverse to auditory perception; musical hallucinations run backwards down neural pathways from the brain to the ear, as if the brain is literally sending music to your ear so your ear can listen to the music and send the signal back to the brain - a feedback loop.

The most astonishing thing is that about 70% of the neural fibers in this area of our brain go in reverse like this.

It seems that we are generally too busy listening to stuff coming in than the stuff going out, but these musical hallucinations overwhelmingly appeared in deaf people.

_{It looks peaceful, but I bet you it's not}

This revelation is strikingly similar to phantom limb syndrome. Many patients who turned deaf midway through life would start hearing these hallucinations constantly.

Michael Chorost

This particular patient speaks to Radiolab about when he went deaf as an adult. Soon after, he started hearing loud ringing which grew and morphed into ethereal music, which would eventually slide into Ave Maria on loop, as if his brain is trying to fill the missing gap - like a lost arm.

Later, he was given a cochlear implant, giving him his hearirng back. As soon as sound was turned on, Ave Maria vanished.

Treatment

I discussed treatment for earworms in the previous post - distraction, basically. For those suffering audio hallucinations, it might actually be easier. In the case of on study, therapy for musical hallucinations was successful with carbamazepine - a drug to treat epilepsy and various neuropathic pain.

I just had to see if there was a connection between epilepsy and earworms but I found little. What I did find is that brain disease in non-dominant hemispheres played an important role in the appearance of musical hallucinations.

Much, much more work needs to be done here, but I find it exciting that there seems to be a connection between Earworms, deafness, epilepsy, schizophrenia, phantom limb syndrome and childhood trauma. In fact, I found some research showing how deaf people process their sense of touch differently by using the auditory cortex somehow... but that's for another day. I'm starting to see why it's not as easy to answer as you might first think!