Spence's job market model
Employers cannot directly observe an applicant's productivity. In his 1973 paper Michael Spence showed that even if education raised productivity not at all, a degree could still signal ability, provided that more able people find it cheaper, in time and effort, to earn. The crucial condition is that signal costs differ by type. Then only high-ability workers choose the degree, producing a separating equilibrium in which employers sort people by credentials; if the cost difference is small, everyone makes the same choice, a pooling equilibrium. The work, a pillar of research on information asymmetry, was cited in Spence's 2001 Nobel Prize.
Game theory and biology
Signaling models are formalized as signaling games in game theory; to prune the many possible equilibria, In-Koo Cho and David Kreps (1987) proposed the intuitive criterion. The same logic arose independently in biology. In 1975 Amotz Zahavi proposed the handicap principle, arguing that costly traits such as a peacock's tail honestly advertise fitness precisely because they are a burden, and Alan Grafen (1990) supplied a formal proof. Much earlier, Thorstein Veblen's The Theory of the Leisure Class (1899) described conspicuous consumption as a display of status, which, along with the Veblen effect, is seen as a forerunner of research on social signals.
Applications and debate
In corporate finance Stephen Ross (1977) argued that leverage and dividends signal managers' private information, and management scholars study warranties, brand advertising, board composition and certifications as signals (Connelly et al., 2011). Signals also matter as remedies for the lemons problem. The value of education is contested between human capital theory, which says schooling raises real productivity, and the view that much of it is merely a signal; Bryan Caplan (2018) argued that signaling dominates, though most empirical studies find both effects at work. The debate connects to discussions of credentials, cultural capital and educational inequality.
FAQ
- How is a signal different from cheap talk?
- A signal is credible because its cost differs by type, making it hard to fake. Costless statements convey information only when interests are aligned; economists call this cheap talk.
- Can credential inflation be explained by signaling?
- Often, yes. Signaling models predict that when everyone acquires the same signal it loses its power to distinguish, pushing people toward ever costlier signals.
Sources reviewed: 2026-10-26
References
- Veblen, T. (1899). The Theory of the Leisure Class. New York: Macmillan.
- Spence, M. (1973). Job market signaling. Quarterly Journal of Economics, 87(3), 355–374.
- Spence, A. M. (1974). Market Signaling: Informational Transfer in Hiring and Related Screening Processes. Cambridge, MA: Harvard University Press.
- Zahavi, A. (1975). Mate selection—A selection for a handicap. Journal of Theoretical Biology, 53(1), 205–214.
- Ross, S. A. (1977). The determination of financial structure: The incentive-signalling approach. Bell Journal of Economics, 8(1), 23–40.
- Riley, J. G. (1979). Informational equilibrium. Econometrica, 47(2), 331–359.
- Cho, I.-K., & Kreps, D. M. (1987). Signaling games and stable equilibria. Quarterly Journal of Economics, 102(2), 179–221.
- Grafen, A. (1990). Biological signals as handicaps. Journal of Theoretical Biology, 144(4), 517–546.
- Connelly, B. L., Certo, S. T., Ireland, R. D., & Reutzel, C. R. (2011). Signaling theory: A review and assessment. Journal of Management, 37(1), 39–67.
- Caplan, B. (2018). The Case against Education: Why the Education System Is a Waste of Time and Money. Princeton University Press.