Japan’s rural areas have been paved over and filled in with roads, dams and other big infrastructure projects, the legacy of trillions of dollars spent to lift the economy from a severe downturn caused by the bursting of a real estate bubble in the late 1980s. During those nearly two decades, Japan accumulated the largest public debt in the developed world — totaling 180 percent of its $5.5 trillion economy — while failing to generate a convincing recovery.

Now, as the Obama administration embarks on a similar path, proposing to spend more than $820 billion to stimulate the sagging American economy, many economists are taking a fresh look at Japan’s troubled experience. While Japan is not exactly comparable to the United States — especially as a late developer with a history of heavy state investment in infrastructure — economists say it can still offer important lessons about the pitfalls, and chances for success, of a stimulus package in an advanced economy.

In a nutshell, Japan’s experience suggests that infrastructure spending, while a blunt instrument, can help revive a developed economy, say many economists and one very important American official: Treasury Secretary Timothy F. Geithner, who was a young financial attaché in Japan during the collapse and subsequent doldrums. One lesson Mr. Geithner has said he took away from that experience is that spending must come in quick, massive doses, and be continued until recovery takes firm root.

Moreover, it matters what gets built: Japan spent too much on increasingly wasteful roads and bridges, and not enough in areas like education and social services, which studies show deliver more bang for the buck than infrastructure spending.