Songs that we have to listen to over and over again , melodies that we are humming mentally all day long, songs that we sing quietly whenever we have the chance… if there is one characteristic that defines the potential that music has in our lives it is that it hooks us, it sticks to us without any kind of commiseration.

It happens, of course, with many simple and catchy melodies, but even the fruits of the greatest technical virtuosity and the most complex musical pieces are capable of making us think about them all the time. Simply put, there are melodies that are practically tattooed on our brain. Why does this happen?

When music is left, it does not leave our head

Some experts refer to the phenomenon of catchy music as a product of the activity of “earworms” . The image of parasites making their nest in our brain and leaving their eggs there is quite unpleasant, but fortunately it is only a metaphor. The idea is that music enters our nervous system through our ears and once there it modifies the way in which our neurons communicate with each other creating a dynamic similar to a loop.

In this way, it is enough that at a specific moment an external stimulus enters our brain (in this case, a melody) for its effects to be perpetuated over time, leaving behind a clear trace: our propensity to reproduce that stimulus over and over again, converted into a memory .

How does this happen? The Science Behind Catchy Melodies

A few years ago, researchers at Dartmouth College shed some light on the mystery of how our brain can simulate the entry of melody into our nervous system over and over again when our ears have already stopped registering this type of stimulus.

An experiment to recognize what happens in the brain

To do this, they conducted an experiment: having a series of volunteers listen to music while their brains are scanned in real time to see which areas of the brain are activated more than others at any given time.

To that end, participants were first asked to choose a series of songs that they are familiar with and others that they have never heard before, so that each person could listen to a personalized list of musical pieces. Once the volunteers had started listening to the music, the researchers included a surprise that had not been explained before: at some points, the music stopped playing for three or four seconds.

Thus, the researchers were able to prove that the part of the brain in charge of processing information related to music is the so-called auditory cortex , and that it continues to be active during those moments when music stops whenever it is familiar, while its activity is interrupted when what stops is unknown music. In other words, when the music is playing, our brain fills in the blanks automatically, without us having to make any effort.

A musical echo that we cannot stop

What does the above tell us about this music that we can’t get out of our heads? Firstly, it tells us that the mental processes we associate with the perception of sensory stimuli can go in the opposite direction to the typical one. In other words, it can be produced from the brain in general towards areas of the nervous system specialized in the processing of sound patterns, since it has been proven that our brain can “continue to sing on its own”.

Secondly, this shows that external stimuli can leave a trail in our brain that, although we may initially ignore, remain latent and can cause us to enter a loop, in the same way that by stirring the water with a stick we can create eddies that remain even when we are no longer touching the water.

Neurons that press “play” automatically

If our brain is in charge of reproducing the way our neurons in the auditory cortex were activated when we were listening to the music coming into our ears, it will also be able to create the chain reaction that derives from this pattern of activation of various neurons coordinating with each other to process the music… which means that the necessary ingredients are mixed again so that in the future the loop appears again.

Further research will be needed to find out why the loop originates, but most likely it has to do with the way certain stimuli create chemical bonds (more or less permanent) between neurons.