Leave a source if you can, please! Last problem - I can't figure it out.
During and after WWI there were a few reactionary art movements, some of the artists you may very well know:
Dada: In Europe there was a general attitude of bitterness and anti-war sentiment following the First World War. It manifested itself into groups of artists that essentially abandoned traditional aesthetic in embrace of "anti-art": a focus on processes and objects/images that were expressly considered non-art. This included the use of "readymades"-- the most famous example being Marcel Duchamp's Fountain-- which were the adoption of pre-manufactured items in art, taking them out from their original designated purpose and using them as sculpture. They also used chance in the creation of their works, keeping a general attitude of absurdity to match their equally disheveled attitude towards the world at that point. The Dada movement extended into critical theory, literature, and performance, though I don't have much authority on the subject.
Some Notable Artists:
It is important to note that many of the Dada artists contributed to the schools of Surrealism and Constructivism later on.
In Germany during and after WWI, there was prevalence of the German Expressionists, New Objectivity and Die Brücke. These artists primarily dealt interaction with culture in the period during and following The Great War, and included critique of the German bourgeoisie and a general attitude of bitterness in reaction to the nationalistic tendencies of the era that they felt were responsible for the start of the conflict.
Some Notable Artists:
After WWI, there was a generally reactive attitude towards war and society, with an embrace of the "unreal" in movements like Dada and Surrealism, and the emphasis on destruction and human degeneracy that can be seen as a response to trauma and horror experienced during the war. On the opposite end of the spectrum there were movements like Futurism that heralded technology, war and advancement-- arguably a manifestation of the nationalism and movement towards war that existed in the early 20th century.