Japanese and American cultures are totally different because of the nature of the society of people that make up the two countries. There are no variations in Japanese culture because most people living in Japan are native to the country, with a very lower percentage of people from other countries.
In contrast, American culture is not general to everybody living in the country, owing to the fact that there are so many ethnic groups in the country, and each ethnic group has its own culture. A lot of traditions have been imported into the United States, and this has caused variations to the American culture.
While the Japanese culture has no divisions or subcultures, the American culture has bred so many subcultures. In Japan, the roles of every member of a family are usually influenced by their tradition. For instance, the husband is usually regarded as the head of the family. In America, the roles of every member of a family are not structured, and the two parents have almost the same rights.