Japanese people have many prejudices, both good and bad, about 外人 (gaijin foreigners), in general, and アメリカ人 (amerika-jin Americans) in particular.
Here are some adjectives that are often used to describe Americans. You might notice a common thread running through them.
- 大らか (おおらか ohraka) - big-hearted, magnanimous, not hung up on little details
- 大声 （おおごえ ohgoe) - loud - loud literally and loud as in opinionated
- 大げさ (おおげさ ohgesa) - exaggerated, exaggerates, over-dramatic.
- 大きい (おおきい ohkii) - big, both in height and weight
The kanji 大 which means big is used in all of these phrases as you can see. Americans have the image of being big and loud and overweight and dramatic. I am guessing this is partly a holdover from the post-war period, when American GIs roamed the streets handing out candy to little Japanese kids, and towered over the short Japanese adults. (My father was a kid in the post-war period, and he still has vivid memories of getting chocolate and chewing gum from big GIs.) And while Japanese people are now a lot taller than they used to be, they are generally a lot skinnier at least than most Americans. (Unfortunately, Americans are generally perceived overseas as being very fat, and getting fatter...which may actually be true.) In addition, American pop culture, not to mention foreign policy and so on, all contribute to that Big/Loud image.
One thing I've noticed about some (not all) Americans who try very hard to fit into the Japanese culture is that they become the opposite of Big/Loud. One recent example is the African-American (he's part Japanese-American also) enka singer Jero, aka Jerome Charles White, Jr. If you don't know Jero, he's a singer who has taken the world of enka, a traditional form of Japanese pop song, by storm. It's the equivalent of a Japanese singer going to Nashville and topping the country charts. Here he is being profiled on an episode of CNN's Talk Asia program:
Whenever I've seen Jero on TV, he's been quiet, soft spoken, polite, obsequitious - exactly the opposite of his hip-hop image. He might already have been like that before entering the Japanese entertainment world, but his non-Big/Loud image has certainly helped him gain fans, especially amongst the traditional enka fan base of middle-aged and older people, especially women. Whether he will help to change the Big/Loud stereotype of Americans, only time will tell.