WASHINGTON — Concerned about waning economic growth, central banks in Europe and China announced measures Thursday to increase borrowing and spending by businesses and consumers, a response that was all the more striking because it was uncoordinated.

Three major central banks announced policy changes in the space of an hour. China’s central bank unexpectedly cut regulated bank lending rates for the second time in four weeks. The European Central Bank cut its benchmark interest rate to 0.75 percent, the lowest level in its 14-year history. And the Bank of England announced it would expand its holdings of government bonds by about 15 percent.

The Federal Reserve announced two weeks ago that it would extend its own bond-buying program until the end of the year.

The actions once again cast central bankers in the role of primary responders to the global economic malaise, aiming at the same basic goal that they have tried to hit repeatedly over the last six years: encouraging people and businesses to borrow and spend and take greater risks with their investments.