Though everybody saw it coming, the announcement last week that China's economy supplanted Japan's as the second largest in the world shocked many people. It matters little that China's sheer size makes its dominance inevitable. What matters is that Japan's 42-year run as the world's No. 2 is over, and if there's anything Japan takes seriously it's its position in the eyes of the world.

And the world is taking notice. Japan has become the prime example of what happens when a mature economy continues to stagnate. Scholar Alexandra Harney analyzed recent Japanese news stories in the online magazine Slate as a means of showing Americans what they may be in for.

She uses the cases of families collecting dead members' pensions and the rise of "parasite singles" to point out how a rich, vital economy can sink so far it has no realistic chance of climbing back up. Low birthrate is a problem, but mainly as a consequence of Japan's "failure to create jobs." The Japanese media has not ignored this connection, but in general they still blame population contraction on social changes rather than economic ones, as if the two were somehow distinct. Men have become less aggressive, women too choosy; so they don't marry and procreate.