Songs are like little balls of Velcro. They have lots of surface area and every micron of area bears a hook to catch in the memory.
Rhythm and rhyme are two of the strongest hooks. Nursery rhymes stick in the memory because of rhythm and rhyme, added to the fact that we learned them as children when our brains were malleable. Songs have these two powerful hooks as well, adding to them melody.
The song’s ability to elicit emotion, whether it be love, pain, regret or joy is a powerful hook. Often a song can call up emotional memories of the first time we heard it, or the phase of life we were in when the song was popular. Songs and memory are inextricable.
However, these song memories live in the right (non-verbal) side of the brain. I know this from a daily occurrence in our house. When my husband and I are not talking, perhaps doing chores or just occupying the same room in silence, he will say, “Have you got a song in your head?”
My answer is invariably the same: “I did until you asked.”
The song had been playing happily in my right brain until his question wakened my left brain, forcing it to label or name it. The title of the song is not the song. I can never recall what song it was. It has disappeared like a dream, into the unconscious whence it came.