Pseudocertainty Effect

Daniel Kahneman and Amos Tversky described the effect in their 1981 paper "The Framing of Decisions and the Psychology of Choice," published in Science. Building on their 1979 prospect theory, they showed that people treat a guaranteed elimination of risk within a multi-stage problem's first phase as truly "certain" — even when the overall outcome remains probabilistic. The finding demonstrated that framing alone could reverse preferences systematically, a result that contributed to Kahneman's 2002 Nobel Memorial Prize in Economic Sciences.