alternative explanation for real economic effects of money supply changes is not that people cannot change prices but that they do not realize that it is in their interest to do so. The bounded rationality approach suggests that small contractions in the money supply are not taken into account when individuals sell their houses or look for work, and that they will therefore spend longer searching for a completed contract than without the monetary contraction. Furthermore, the floor on nominal wages changes imposed by most companies is observed to be zero: an arbitrary number by the theory of monetary neutrality but a psychological threshold due to money illusion. Neutrality of money has been a central question for monetarism. The most important answers were elaborated within the framework of the Phillips curve. Milton Friedman, assuming adaptive expectations, distinguished a series of short-run Phillips curves and a long-run one, where the short-run curves were supposed to be the conventional, negatively sloped curves, while the long-run curve was actually a vertical line indicating the natural rate of unemployment. According to Friedman, money was not neutral in the short run, because economic agents, confused by the money illusion, always respond to changes in the money supply. If the monetary authority chooses to increase the stock of money and, hence, the price level, agents will be never able to distinguish real and nominal changes, so they will regard the increase in nominal wages as real modifications, so labour supply will also be boosted. However, this change is only temporary, since agents will soon realize the actual state of affairs. As the higher wages were accompanied by higher prices, no real changes in income occurred, that is, it was no need to increase the labour supply. In the end, the economy, after this short detour, will return to the starting point, or in other words, to the natural rate of unemployment. New classical macroeconomics, led by Robert E. Lucas, also has its own Phillips curve. However, things are far more complicated in these models, since rational expectations were presumed. For Lucas, the islands model made up the general framework in which the mechanisms underlying the Phillips curve could be scrutinized. The purpose of the first Lucasian island model (1972) was to establish a framework to support the understanding of the nature of the relationship between inflation and real economic performance by assuming that this relation offers