REAL BUSINESS CYCLE THEORY:
The parable that motivates this discussion originated with Edmund Phelps and invites you to think that all men (and women) are islands. They have perfect information about the prices of goods and services on their islands but cannot sample the prices on other islands except by rowing there, a costly activity. Consequently, they can only form estimates of the general price level, the average of all prices. Thus, an increase in the general price level will be misperceived as an increase in the price of goods on the island, a (small) subset and, therefore, sub optimal decisions about consumption, production, and investment will be taken. In the spirit of the earlier section, the following account in the next is drawn from the book:
Barro, Robert, Macroeconomics, New York: John Wiley & Sons, Inc.