The thing about cultural expression is an interesting idea. In Japan the culture was so much more contained, the evolution of the forms so much slower. Here in America, the culture is a true melting pot. To express this culture is not a simple form or idea. It will vary from state to state, town to town, neighborhood to neighborhood. It will never develop like Japanese pottery. That is not a bad thing. It is true. The huge variations and choices we have within our own studios ARE reflective of our culture.
When I was studying art (painting) in NYC back in the early 80's, it would not remain 2D. It broke out in 3D with plaster, chicken wire, wax, wood. The museums and galleries reflected a lot of this genre.
I spent one summer back then in San Francisco in a painting class at San Francisco Art Institute. I gathered mediums for the class, but all I felt compelled to work with was colored pencils and water colors on paper.
The air, the culture, the smell, the energy, the people, all different. It affected me.
Maybe one should take Hamada's comment about adding granite to the clay as just about that specific act.