Institute for Mathematical Behavioral Sciences

A new foundation is presented for the theory of subjective judgments of probability generally known as “Support Theory.” It is based on a new complementation operation that, unlike those of classical probability theory (set theoretic complementation) and classical logic (negation), does not satisfy the principle of The Law Of The Excluded Middle Interrelationships between the new complementation operation and the Kahneman and Tversky judgmental heuristics of availability and representativeness are described, and alternative explanations are provided for experimental studies involving subjective judgments of probability.