McGill neuroscientist Dan Levitin writes, in a Washington Post op-ed piece on the 40th anniversary of the release of the Beatles' eighth album, "Sgt. Pepper's Lonely Hearts Club Band": "A hundred years from now, musicologists say, Beatles songs will be so well known that every child will learn them as nursery rhymes, and most people won't know who wrote them. They will have become sufficiently entrenched in popular culture that it will seem as if they've always existed, like 'Oh! Susanna,' 'This Land Is Your Land' and 'Frère Jacques'... Figuring out why some songs and not others stick in our heads, and why we can enjoy certain songs across a lifetime, is the work not just of composers but also of psychologists and neuroscientists."