A song playing comprises a very specific and vivid set of memory cues. Because the multiple-trace memory models assume that context is encoded along with memory traces, the music that you have listened to at various times of your life is cross-coded with the events of those times. That is, the music is linked to events of the time, and those events are linked to the music.
The most important, the longest lasting, the strongest emotional, and the most practiced memories are the ones that are embedded the deepest in the brain, and because we have retrieved them so many times previously, they are the most able to be retrieved. We all hear about people who can remember their youth, their phone number, or street address from 70 years ago, but they cannot recall what they had for breakfast. The memory of this morning's breakfast wasn't rehearsed, and wasn't very important, so it fades away quickly.
The mammalian brain evolved exquisite place memory because that was essential for survival. This is why squirrels have such a good memory for where they buried their nuts.
