(Reuters) - Artificial intelligence is speeding the rate at which investors react to specific sentences in central bankers' speeches and in statements describing their policy actions, Federal Reserve Vice Chair Philip Jefferson said on Friday, but it's unclear whether that increased speed is boosting or hindering the effective transmission of monetary policy.

"For now, I do not think artificial intelligence is changing the way policymakers communicate, but research shows that it has affected how quickly information about policy is incorporated into asset prices," Jefferson said in prepared remarks to a conference at the San Francisco Fed that did not touch on his outlook for monetary policy or the U.S. economy. 

Further research is needed, he said, to determine whether the faster speed is allowing monetary policy to get transmitted faster through the economy, or, as some worry, that it "may provide an incentive for investors to value speed over accuracy, and may reduce the long-run informativeness of asset prices, which could hurt the transmission of monetary policy." 

In any event, Jefferson said, research makes it clear that it's not just investors but also households that pay attention and respond to monetary policy pronouncements. Policymakers, he said, "should communicate as clearly as possible to avoid increasing uncertainty."