Money Illusion

Origins and debate

Fisher (1928) observed that people treat the dollar as a fixed measure of value and fail to recognize that its purchasing power itself rises and falls, calling this money illusion. Keynes (1936) held that workers accept falling real wages due to rising prices while strongly resisting cuts in nominal wages, which Leontief (1936) critically interpreted as assuming that workers suffer from money illusion. Tobin (1972) regarded downward rigidity of nominal wages as important to explaining the relationship between inflation and unemployment. Economists emphasizing rational expectations, by contrast, tended to exclude money illusion from the basic assumptions of theory, arguing that rational agents should not confuse nominal and real magnitudes.

Experimental evidence from behavioral economics

In surveys by Kahneman, Knetsch and Thaler (1986), people judged a 7% wage cut with no inflation as unfair but a 5% raise with 12% inflation as fair, even though real wages fell by the same amount. Shafir, Diamond and Tversky (1997) explained money illusion as arising because nominal and real representations come to mind simultaneously and the nominal frame, being easier and more salient, seeps into judgment. Fehr and Tyran (2001) showed in laboratory price-setting games that presenting payoffs in nominal terms greatly slowed price adjustment after a money supply shock, reporting that small individual money illusion can be magnified through strategic interaction into economy-wide nominal rigidity. Weber and colleagues (2009) reported brain-imaging evidence that activity in reward-related brain regions is greater when nominal amounts are larger, even for identical real payoffs.

Macroeconomics and asset markets

Akerlof, Dickens and Perry (2000) argued that at low inflation, near-rational behavior in which people do not fully account for price increases can create a long-run trade-off in which modest inflation lowers unemployment. This fed into debates on the Phillips curve and optimal inflation targets. In asset markets, Modigliani and Cohn (1979) argued that investors mistakenly discount real stock cash flows at nominal interest rates, undervaluing stocks when inflation is high. Cohen, Polk and Vuolteenaho (2005) reported evidence supporting this hypothesis, and Brunnermeier and Julliard (2008) argued that when inflation and nominal rates fall, people may confuse changes in real rates, fueling excessive house price increases. Money illusion is treated alongside the framing effect and bounded rationality as a concept for understanding how economic agents actually judge.

FAQ

What is money illusion in simple terms?

If your salary rises 3% while prices rise 5%, you can actually buy less, yet you may feel better off because the number on your paycheck went up. That is money illusion.

How does money illusion affect the economy as a whole?

When people judge in nominal terms, wages and prices may not adjust quickly to changes in the price level, creating nominal rigidity. This links to debates on how monetary policy affects the real economy, the optimal level of inflation, and movements in stock and house prices.

Sources reviewed: 2026-10-26

References

1. Fisher, I. (1928). The Money Illusion. New York: Adelphi.
2. Keynes, J. M. (1936). The General Theory of Employment, Interest and Money. London: Macmillan.
3. Leontief, W. (1936). The fundamental assumption of Mr. Keynes' monetary theory of unemployment. Quarterly Journal of Economics, 51(1), 192–197.
4. Tobin, J. (1972). Inflation and unemployment. American Economic Review, 62(1/2), 1–18.
5. Modigliani, F., & Cohn, R. A. (1979). Inflation, rational valuation and the market. Financial Analysts Journal, 35(2), 24–44.
6. Kahneman, D., Knetsch, J. L., & Thaler, R. (1986). Fairness as a constraint on profit seeking: Entitlements in the market. American Economic Review, 76(4), 728–741.
7. Shafir, E., Diamond, P., & Tversky, A. (1997). Money illusion. Quarterly Journal of Economics, 112(2), 341–374.
8. Fehr, E., & Tyran, J.-R. (2001). Does money illusion matter? American Economic Review, 91(5), 1239–1262.
9. Akerlof, G. A., Dickens, W. T., & Perry, G. L. (2000). Near-rational wage and price setting and the long-run Phillips curve. Brookings Papers on Economic Activity, 2000(1), 1–60.
10. Brunnermeier, M. K., & Julliard, C. (2008). Money illusion and housing frenzies. Review of Financial Studies, 21(2), 135–180.
11. Cohen, R. B., Polk, C., & Vuolteenaho, T. (2005). Money illusion in the stock market: The Modigliani-Cohn hypothesis. Quarterly Journal of Economics, 120(2), 639–668.
12. Weber, B., Rangel, A., Wibral, M., & Falk, A. (2009). The medial prefrontal cortex exhibits money illusion. Proceedings of the National Academy of Sciences, 106(13), 5025–5028.