I can't speak for all Westerners, just Americans, because we are definitely the most ignorant of geography of the Western nations.
In the US, Japan and China might not be the only Asian nations most people have ever heard of, but they would probably be the only one they could find on a map.
Years ago there was an animated sitcom on TV about a family living in a suburb in Texas, called King of the Hill. There was a character in this series who was from Laos, named Kahn. People in the neighborhood would ask him if he was from Japan or China. He'd tell them he was from Laos, and then they would ask 'Well, is that in Japan or in China?' I don't think most of us are quite -that- ignorant. 8^)
But I would doubt that half of us could show you were Laos was on a map. I think a lot of people might look on the wrong continent.