Final answer:
The active monetary policies of the 1960s were based on an inverse relationship between inflation and unemployment suggested by the Phillips curve. Over time, recognition of people's adaptive expectations resulted in the Federal Reserve employing more passive monetary policies aiming for fewer surprises.
Step-by-step explanation:
The active monetary policies of the 1960s relied on the Phillips curve, which indicated a trade-off between inflation and unemployment.
Policymakers assumed an inverse relationship between unemployment and inflation, hoping this would hold in the long run. However, this approach failed as both inflation and unemployment increased, which led to a shift in the Phillips curve.
Recently, the Federal Reserve adopted more passive monetary policies. These policies acknowledge that people adjust their inflation expectations over time, leading the Fed to aim for fewer surprises in monetary policy to maintain economic stability.