Re: common symbolism in art.
I was wondering the other day if most art have a common type of symbolism in them. That maybe the common observer wouldn't pick up on, but an educated artist would?
This question would probably be better posted in the Art History forum as it deals with an element of Art History known as "iconography". You question is incredibly broad. The simply answer would be "yes"... many works of art are laden with various forms of symbolism or iconography that are quite common... or rather frequently employed. Also... "yes" the more the viewer is educated in Art History the more likely he or she will pick up upon such iconography. A lot of the art embraced today by academia and the big collectors employs an an imagery or alludes to concepts or ideas that are increasingly esoteric... essentially as a means of differentiating the "sophisticated and cultured" "elite" who "get it" from the rest of the audience.
The purpose of such iconography in the past was the exact opposite. Art was a means of communicating the important narratives (of the Bible or the great Kings and rulers) to a largely illiterate audience. Everyone recognized that an image of a young woman dressed in a blue robe (lined with red) and holding a baby was the Holy Virgin... while a woman dressed in green or red (often with red hair) was clearly Mary Magdalene (the scarlet woman).
Until the late 19th or 20th century the artist could be relatively certain that the usual audience for his or her painting was well versed in the narratives and iconography of the Bible, the Greco-Roman myths, and various classic texts (Shakespeare, Goethe's Faust, Cervantes' Don Quixote, Dante, etc...). As the audience for the arts grew as a result of increased literacy, increased access to education, increased leisure time... and the increasingly multicultural nature of the Western societies, the culture lost much of this collective narrative... something T.S. Eliot addresses in his Wasteland as a form of elegy. It is for this reason that art beginning with the 19th century Realists and Impressionists shifted away from illustrating these great narratives and toward the everyday experiences. More Modern artists wishing to be assured of the audience's grasp of the narratives they employ may build upon narratives and characters and imagery drawn from popular culture.
"Beauty is truth, truth beauty—that is all ye know on earth and all ye need to know." - John Keats
"Modern art is what happens when painters stop looking at girls and persuade themselves that they have a better idea."- John Ciardi