A Google Images search for “popular culture” brought up for me a lot of images from the 1950s; Marilyn Monroe, Elvis, and Andy Warhol paintings of Marilyn Monroe and Elvis (popular culture seems to be very self-referential). Yet the western official culture goes back thousands of years, to Homer and Plato and Aristotle – why is one so ancient and the other so recent? It has something to do with the way cultural works are transmitted – the 1950s were the decade when most families in the US got their first TV.
Before the 20th century, the best way to preserve and transmit culture was with books. Books made it possible for culture to be transmitted across space and time, so that it could survive and continue developing.
However books had to be painstakingly copied out by hand and they were therefore very expensive. For the most part only the wealthy could afford them. The official culture – the culture that included works of art, poetry, philosophy, astronomy, and mathematics – was the culture of the upper class, who didn’t need to work for a living and thus could afford to devote large amounts of time to learning just for the sake of learning. (It’s only fairly recently that academic jobs have existed, making it possible for people who aren’t independently wealthy to become scholars, and even today there are many extra barriers to academia for people from low-income families.) The official culture, the culture of the aristocracy, was the one that was written down in books.
On the other hand the culture of ordinary people – for example, songs and dances, stories and myths, language, religion, customs, styles of clothing, and ways of cooking, building, pottery-making, and weaving cloth – was transmitted through person-to-person contact over an extended period of time. These cultures were local to a particular geographic area. They were transmitted slowly, and could not make big jumps through space or time.