SINTRA, Portugal — The rise of robots has long been a topic for sci-fi best sellers and video games and, as of this week, a threat officially taken seriously by central bankers.

The bankers are not yet ready to buy into dystopian visions in which robots render humans superfluous. But, at an exclusive gathering at a golf resort near Lisbon, the big minds of monetary policy were seriously discussing the risk that artificial intelligence could eliminate jobs on a scale that would dwarf previous waves of technological change.

“There is no question we are in an era of people asking, ‘Is the Robocalypse upon us?’” David Autor, a professor of economics at the Massachusetts Institute of Technology, told an audience on Tuesday that included Mario Draghi, the president of the European Central Bank, James Bullard, president of the Federal Reserve Bank of St. Louis, and dozens of other top central bankers and economists.

The discussion occurred as economists were more optimistic than they had been for a decade about growth. Mr. Draghi used the occasion to signal that the European Central Bank is edging closer to the day when it will begin paring measures intended to keep interest rates very low and bolster the economy.