Throughout "The Hairy Ape" Eugene O"Neill manages to incorporate three very different elements into the play write. Each of these elements, expressionism, realism, and symbolism are sometimes combined as one, or expressed alone to place more emphasis on a particular event. .
Realism can be seen in many scenes throughout the play, but especially the aspect of the industrialization of the workers. All of these men are almost seen as programmed to do their job, with out showing many emotions and also lacking much thought, like an "ape". This was a very realistic approach in objectifying their common, average, everyday routine. None of these men are required to have much thought, but purely a strong caliber for physical work. The firemen are at one point even said to be "ape" like, as Paddy is described "extremely monkey-like". As these men work harder and longer, they are being stripped from reality and moving closer to a Neanderthal state of mine. It is easily seen as to what their class and status by their experiences. This type of depiction in the beginning of the play helps understand the reasoning for Yank actually becoming an "ape" in the Zoo.
Expressionism and a little realism are represented by the societal classes. Mildred and Yank have very different lifestyles, although they both have concerns with their status. Mildred wants something more exciting, and even says at one point that she wants to basically touch "life", and see what it has to offer beyond her very secluded manner. On the other hand Yank has felt that this "life" Mildred speaks of has been too much a part of his life, and he is seeking to overcome the structure of the classes. Yank finds "belonging" very important. These too very different views of life objectify the inner experiences of these two very different characters.