Postmodernism is interesting because it seems as if the artists of this movement were on a mission to create something never seen before. Also interesting to me is that postmodernism rejects modernism at the same time it shows knowledge of modernism. I guess this is a reflection of the times.
When Dada started it was post WW I and many parts of life was in a state if recovery and growth. Many of the pieces seem very dark or confusing to me.
Pop art also reflected the times as the art was reflecting everyday life both in the USA and England. Most people were watching television, reading magazines and comic books. Lichtenstein's work reminds me of comic books and commercial advertisements.
Due to art reflecting the times one sees more of gender issues and roles in postmodernism. An example of this is the feminism art movement. This movement has female artists changing the perception or reflecting on the female role in society.