The Science Behind Earworms: How Music Sneaks Into Your Brain

Okay, imagine this: You're brushing your teeth, minding your own business.

But suddenly, and out of nowhere, “Call Me Maybe” starts playing on repeat in your head. You didn't ask for it. You didn't want it. But there it is — the irritating earworm.

Why does this happen? Well, let's go back to the basics.

Music is, at its core, a series of vibrations traveling through the air. These sound waves are funneled in through the pinna, the outer part of your ear, and they travel all the way to the cochlea inside your inner ear.

Inside the cochlea, tiny sensory receptors called hair cells bend in response to specific frequencies. When they bend, they activate ion channels that convert those vibrations to electrical signals.

These signals travel via the vestibulocochlear nerve to the brainstem, making several pit stops along the way. First, to the cochlear nuclei in the medulla. Then, to the superior olivary complex, which helps determine where a sound is coming from. Next, to the inferior colliculus in the midbrain. Onward to the medial geniculate nucleus of the thalamus. And finally, they reach the primary auditory cortex in the temporal lobe, allowing us to hear sounds.

But how do we form thoughts about music? Here's where the limbic system kicks in. This network of brain structures helps process emotion and memory. It includes the thalamus, which is a relay center for sensory information; the amygdala, which is important for emotional reactions; and the hippocampus, which is crucial for memory formation.

The hippocampus forms associations between the music you hear and memories, emotions, or even routines. That's why a song can become linked to walking to school, hanging out with your friends, or even that one awkward middle school dance. Once this connection is made, the brain might replay the song spontaneously — especially when you're doing idle or repetitive tasks. That's your earworm.

Catchy music also activates the brain's dopaminergic system. This means music can trigger the release of dopamine, a neurotransmitter associated with reward, pleasure, and motivation. It's the same system involved in eating chocolate, watching your favorite TV show, or placing that final piece in the jigsaw puzzle.

When dopamine is released, the amygdala creates associations between whatever caused the dopamine release and positive emotions. This makes you want to experience that feeling again, which is part of the reason why your brain wants to keep repeating catchy music.

Another factor that heavily influences the catchiness of music is its beat. According to the neural resonance theory of musical meter, your brain's electrical activity can synchronize with rhythmic patterns in music. When a song has a strong beat, your brain waves may start to fire at the same frequency as that beat.

This synchronization spreads to the areas of the brain that control movement, such as the primary motor cortex (which controls the initiation of voluntary movement), the basal ganglia (which coordinate the actual movements and also link it to emotions), and the cerebellum (which fine-tunes timing and balance). That's why your foot taps without thinking, or why rhythms stick in your head and make you feel like dancing.

An earworm is basically the perfect storm: a memorable melody, dopamine reward activation, a strong rhythm that aligns with brain waves, a memory or habit connection through the hippocampus, and also a quiet moment when your brain fills the silence with, well, “Call Me Maybe.”

Your brain is just doing what it's wired to do — remember, predict, and enjoy music. You just didn't expect it to happen while brushing your teeth, did you?