Powered by healthy spending from increasingly optimistic consumers, the American economy is emerging as an island of relative strength in the face of renewed torpor and turmoil elsewhere in much of the world.

Just hours after Russia unexpectedly cut interest rates on Friday in response to a shrinking economy and worries over its banks, and European officials reported more signs of weakness on the Continent, new government data showed the American economy grew at a decent 2.6 percent rate in the final quarter of 2014.

That pace represents a downshift from the blistering 5 percent growth rate recorded in the third quarter and was modestly below what economists had been expecting. Nonetheless, most economists viewed the report in a positive light and saw the robust consumer spending as pointing to an improving economy in 2015.

The combination of plunging energy prices and a healthier job market in late 2014 helped consumer spending rise last quarter by 4.3 percent, the fastest rate of growth since early 2006. And in a separate report on Friday, the Thomson Reuters/University of Michigan survey of consumer sentiment in January rose to its highest level since January 2004.