Federal Reserve officials now seem open to deploying negative interest rates to combat the next serious recession even though they rejected that option during the darkest days of the financial crisis in 2009 and 2010.

“Some of the experiences [in Europe] suggest maybe can we use negative interest rates and the costs aren’t as great as you anticipate,” said William Dudley, the president of the New York Fed, in an interview on CNBC on Friday.

The Fed under former chairman Ben Bernanke considered using negative rates during the financial crisis, but rejected the idea.

“We decided — even during the period where the economy was doing the poorest and we were pretty far from our objectives — not to move to negative interest rates because of some concern that the costs might outweigh the benefits,” said Dudley.

Bernanke told Bloomberg Radio last week he didn’t deploy negative rates because he was “afraid” zero interest rates would have adverse effects on money markets funds -- a concern they wouldn’t be able to recover management fees -- and the federal-funds market might not work. Staff work told him the benefits were not great.

But events in Europe over the past few years have changed his mind. In Europe, the European Central Bank, the Swiss National Bank and the central banks of Denmark and Sweden have deployed negative rates to some small degree.

“We see now in the past few years that it has been made to work in some European countries,” he said.

“So I would think that in a future episode that the Fed would consider it,” he said. He said it wouldn’t be a “panacea,” but it would be additional support.

In fact, Narayana Kocherlakota, the dovish president of the Minneapolis Fed, projected negative rates in his latest forecast of the path of interest rates released last month.

Kocherlakota said he was willing to push rates down to give a boost to the labor market, which he said has stagnated after a strong 2014.

Although negative rates have a “Dr. Strangelove” feel, pushing rates into negative territory works in many ways just like a regular decline in interest rates that we’re all used to, said Miles Kimball, an economics professor at the University of Michigan and an advocate of negative rates.

But to get a big impact of negative rates, a country would have to cut rates on paper currency, he pointed out, and this would take some getting used to.

For instance, $100 in the bank would be worth only $98 after a certain period.

Because of this controversial feature, the Fed is not likely to be the first country that tries negative rates in a major way, Kimball said.

But the benefits are tantalizing, especially given the low productivity growth path facing the U.S.

With negative rates, “aggregate demand is no longer scarce,” Kimball said.