You’re walking down a busy street on your way to work. You pass a busker playing a song you haven’t heard in years. Now suddenly, instead of noticing all the goings on in the city around you, you’re mentally reliving the first time you heard the song. Hearing that piece of music takes you right back to where you were, who you were with and the feelings associated with that memory.
You’re sitting on the plane, staring out of the window at the clouds and all of a sudden, you think back to how a few months ago, you had a heart-to-heart with a good colleague about the pressure you experience at work. How do thoughts seemingly completely unrelated to the present pop into our heads? Why do we remember certain things and not others? Why does our mind go off on tangents and why do we have daydreams?