Much time was wasted and ink spilled in the late 1960s and early 1970s trying to interpret the lagged effect of prices on wages as reflecting adaptive lags in the formation of expectations. But if we have learned anything from the new Keynesian economics of Fischer, Taylor, Blanchard, and their younger followers, it is that price and wage inertia is compatible with rational expectations.

Robert J. Gordon, The Phillips Curve Now and Then. (1990).