We’ve all experienced the phenomenon commonly known as an ‘earworm’ where we feel we can hear a song or piece of music whilst none is actually playing. These tunes or Involuntary Musical Images (thanks Wiki) can come from absolutely nowhere and may indeed be songs that you haven’t heard in years, but for some reason they just worm their way into your brain. But what is behind this inner discotheque?

Now many people will believe that an earworm is some kind of mental aberration that the mind simply conjures up from the depths of our subconscious, but the reality is far more interesting than that. However, let’s not get ahead of ourselves and look at a little of earworms in antiquity – and we need to go right back into prehistory to do this.

The cave paintings at Lascaux near the village of Montignac in the Dordogne department of France are best known for their paintings of various animals and are now commonly believed to be created some 17 000 years ago. Amongst the various chambers dedicated to specific animals, or groups of animals, is one smaller room that Henri Breuil, the Catholic Priest commonly known as Abbé, and responsible for the original sketches of the cave complex’s paintings named the Chambre des Bruits (Chamber of Noises). In this room there are numerous paintings that seem to depict human heads with other humans within their heads beating what look like rocks with sticks, or shouting (singing?). Originally it was thought that these images were portraying members of the prehistoric community experiencing possession by unknown forces – there are skull fragments in the area with what are believed to be trepanation holes that are considered to be by way of ‘releasing’ the uninvited spirits. However, and echoing the name that Abbé gave the room with these images, it is widely assumed that what is actually being illustrated is our friend the earworm.

Throughout history many novels and philosophers have made mention of these inner ‘musical’ episodes, with Mark Twain’s 1896 short story ‘A Literary Nightmare’ (or ‘Punch, Brothers, Punch!’) describing how a particularly musical poem he read in a newspaper became lodged in his head rendering him incapable of writing and effectively becoming a ranting loon.

In 2016 researchers at the St Andrews (Scotland) School of Philosophical, Anthropological and Film Studies came up with a formula for predicting a song’s likelihood of becoming an earworm. That formula is expressed as follows: Receptiveness + (predictability-surprise) + (melodic potency) + (rhythmic repetition x1.5) = earworm. This team declared Queen’s ‘We Will Rock You’ as the ultimate earworm. Admit it…it’s in there right now isn’t it?

But what is the actual mechanism that allows an earworm to become so lodged in our brains? To answer this we need to travel back in time again, but not too far, to the early Spring of 1836 and the town of Shrewsbury in England where the illegitimate and slightly simple sibling of Charles Darwin, Herbert Darwin (though more commonly known in the area by his unmarried mother’s surname Howells) resided. Herbert Howells was somewhat in awe of his brother’s exploits – Charles having departed on the Beagle’s epic voyage of discovery shortly after Christmas in 1831 and not to return until early October 1836. These dates are important with regards the earworm, dear reader!

Not to be outdone by his brother, Herbert, a wealthy young man in his own right, commissioned a small boat called the Labrador that set sail from Plymouth on the 27th December 1835, but only getting as far as the small Breton fishing port of Perros Guirec in North West France. Herbert, despite his apparent simple demeanour, was actually highly intelligent in many ways, but tended to be very narrow in his areas of expertise, and with that obsessiveness for a particular topic changing regularly. During the Spring and Summer of 1834 it is documented in his mother’s diary that Herbert’s obsession du jour was the “Minstrels in my (his) mind.” Again documented in his mother’s journal, he was visited on several occasions by physicians and priests to rid of him of these voices in his head. However, Herbert was not convinced by the quacks and shavelings and conjectured that something else was afoot with regards these internal musical recitals.

Upon landing in Brittany, Herbert made his base the Château de Kergouanton, fifteen kilometres inland of where he disembarked, in the small town of Trélévern. It was from here that he conducted his research into what he considered may be the cause of the music in his mind. During his time at the Chateau, Herbert’s behaviour was becoming quite bizarre and he was found to be spending more and more time in his make-shift ‘laboratory’ examining the fauna of the area, with one particular, and until then unknown species becoming the intense focus of his mania.

In October 1859, and around a month before Charles Darwin published ‘On the Origin Of Species’, Herbert self-published a pamphlet with the title ‘Lampyris musica – An Original Species’. Needless to say this publication was far out shadowed by Charles’ book and was essentially forgotten until it resurfaced in late 2017, coincidentally in St Mary’s College Library at St Andrews University. Essentially, the pamphlet, now largely moth-eaten, describes what Herbert called his ‘Earworm’s’ lifecycle in great detail, though the hand-drawn images are barely decipherable – much like the cave paintings where we started this story.

Lampyris noctiluca (the Firely, or Glowworm) and its lifecycle had been documented for some time, and Howell’s Lampyris musica is very closely related and has a similar, if not wholly different, modus operandi. Herbert found that the earworm, whilst largely a nocturnal beetle found in the hedgerows of where he was staying in Brittany, actually and in the main, laid its eggs on cotton and linen – obviously bed linen was a perfect hatchery for the minute eggs and once they hatched Hubert found that they would enter a person’s nasal cavity and burrow, without any discomfort, pain or damage, right into the centre of a person’s brain where they would sit symbiotically until maturity when they would begin to search for a mate.

Now this is the important distinction between the Glowworm and the Earworm – where the Glowworm uses bioluminescence in order to attract a mate, the Earworm feeds on energy from the brain’s auditory cortex, the part that handles information from your ears and holds on to musical memories – this is why when I mentioned the Queen song We Will Rock You earlier, you heard it – the mature beetle was feeding off your auditory cortex (as it is now). The energy is converted into the music we hear by ever so tiny bioamplifiers (Class D for those who have interest) and miniscule loudspeakers (bookshelves with EMT tweeters) located in the abdomen of Lampyris musica. Have you ever wondered why the music you are hearing isn’t actually being heard in your ears as such and seems to be coming directly from the centre of your brain – well now you know.

Once a mate has been attracted the individual earworm will cease to emit the music, the bioamplifier and loudspeakers will be turned off, and he/she will wait for a response from the prospective suitor, often heard by us a short burst of tinnitus to the host. This triggers the earworm to begin its descent into the world where the whole cycle will start again. Of course, such is the nature of this symbiotic relationship that the host, apart from the inner music, is blissfully unaware that they are being used as a pick-up joint for beetles.

Interestingly, once the beetles descend from your brain they congregate in large numbers in fields, turn their amplifiers and loudspeakers back on, capture a ‘technohead’ host and take part in what scientists have called Beetle Manias or Worm Raves until the Chucky Pigs (Woodlice) turn up and arrest them all.

And there you have it. I feel it is such a shame that the timing of Herbert’s publication of his findings coincided so significantly with the publication of his brother’s much more weightier and widely read tome, otherwise we would have libraries and university halls named after him rather than his brother.

It is also sad that in the years following Herbert’s publication that the term “He’s a bit of a Herbert” became a common phrase to mean that someone was a bit of a fool.