Final answer:
The most influential paradigm shift in Western culture that has affected America is the shift from traditionalism to modernism during the 1920s.
Step-by-step explanation:
One of the most influential paradigm shifts in Western culture that has affected America is the shift from traditionalism to modernism during the 1920s. This shift represented a move towards more progressive and liberal thoughts and ideas, challenging traditional values and norms. Examples of social and cultural changes during this time include the women's suffrage movement, the emergence of jazz and the new youth culture, the Prohibition era, and the questioning of religious beliefs.