Here's why:
* Shattered Ideals: The war shattered the sense of optimism and progress that characterized the 19th century. The horrific violence and loss of life deeply affected writers, leading them to question traditional values and beliefs.
* Shifting Social Landscape: The war also brought about significant social changes, such as the rise of mass media and a growing urban population. These changes challenged traditional ways of life and fostered a sense of alienation and fragmentation, themes often explored by modernist writers.
* European Modernism: American writers were heavily influenced by European modernist movements, like Dadaism, Surrealism, and Cubism. These movements challenged traditional forms of art and literature, embracing experimentation, fragmentation, and the exploration of the subconscious.
* Psychological Exploration: The trauma of war and the resulting social changes led to a greater interest in psychology. Freud's theories of the unconscious, particularly the concept of the id, ego, and superego, influenced the modernist exploration of internal conflicts and the fragmented nature of the human psyche.
While WWI was the most significant catalyst, other influential factors included:
* Rapid Industrialization and Technological Advancements: The rapid changes in technology and the rise of mass production contributed to a sense of alienation and disorientation, themes explored by modernist writers.
* The Harlem Renaissance: The flourishing of African American art and culture in Harlem during the 1920s had a profound impact on American modernism, particularly in terms of its themes of race, identity, and social injustice.
In summary, American modernist writers were influenced by a complex web of factors, but the impact of WWI and its aftermath was arguably the most significant, shaping their themes, aesthetics, and perspectives.