I found an interesting little video on this subject here: http://bigthink.com/think-tank/the-beholders-response-how-the-brain-responds-to-ambiguity-in-art
In the video the author argues that its the very ambiguity of art that makes it great. Interesting, because of course ambiguity in art means that such art can transcend time and place and so probably has a longer life span than art with very fixed meaning because once its cultural references go then it becomes meaningless.
Any thoughts?