Hi-
one of the effects on art was that European artists fleeing fascism went to America taking concepts of abstraction, dada, surrealism, cubism etc which got mixed with American ideas. It first emerged as Abstract Expressionism, which was very non-figurative and cerebral in it's concept.
I think that post-WW2 art was more a reflection of society, it's move towards consumerism, the pop explosion, beat happenings, sixties' psychedelia etc etc, all of which were no doubt facilitated by the war- especially in Britain where there was growing self-awareness amongst the working class, increased affluence and aspirations; social barriers were beginning to be eroded and so forth. European art post WW2 was largely influenced by the American schools.
That's about all I can offer on the subject

Hope it helps.
MC