The Federal Reserve, while slow to see the credit crisis spilling into the broader economy last year, has acted much more decisively in recent weeks. The Fed has twice cut short-term interest rates sharply, lowering its benchmark rate to 3 percent, reflecting both the central bank’s anxiety and its determination to try to lift the economy despite serious concerns about the risk of higher inflation.

Ben S. Bernanke, the Fed chairman, is a former professor at Princeton University and a student of Japan’s policy missteps. And while a number of experts fault Mr. Bernanke for what they see as the Fed’s poor communications with both Main Street and Wall Street, the central bank’s recent moves suggest that he has taken those lessons to heart.

His past comments, however, indicate that Mr. Bernanke thinks that low interest rates alone are not enough to revive an ailing economy. In a 2003 speech in Tokyo, for example, he offered a prescription for Japan’s malaise: a more aggressive monetary policy and “explicit, though temporary, cooperation between the monetary and fiscal authorities” to stimulate the economy.

Washington understands that message. Congress  America’s fiscal authority  moved unexpectedly rapidly to approve a $168 billion stimulus plan that includes household tax rebates, temporary tax cuts and incentives for business investment.

“The United States is moving faster than the Japanese did,” said Charles Yuji Horioka, a professor of economics at Osaka University. “So far, so good. But American policy makers have to be ready to take further steps as needed.”

The American economy, many economists predict, will deteriorate further before things turn around. The government’s report last week that employment fell in January, the first decline in more than four years, was the latest sign of trouble. The depth and duration of the downturn, economists say, will largely depend on how much more bad news is coming from banks and other financial institutions.

Nouriel Roubini, an economics professor at the Stern School of Business at New York University, warned that the roughly $100 billion in bad loans reported by banks to date could increase nearly tenfold, as the defaults spread beyond the subprime mortgage loans to consumer loans, credit cards and corporate lending.