Accession Number : ADA568559


Title :   The Probabilities of Unique Events


Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC


Personal Author(s) : Khemlani, Sangeet S ; Lotstein, Max ; Johnson-Laird, Phil


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a568559.pdf


Report Date : 30 Aug 2012


Pagination or Media Count : 35


Abstract : Many theorists argue that the probabilities of unique events, even real possibilities such as President Obama's re-election, are meaningless. As a consequence, psychologists have seldom investigated them. We propose a new theory (implemented in a computer program) in which such estimates depend on an intuitive non-numerical system capable only of simple procedures, and a deliberative system that maps intuitions into numbers. The theory predicts that estimates of the probabilities of conjunctions should often tend to split the difference between the probabilities of the two conjuncts. We report two experiments showing that individuals commit such violations of the probability calculus and corroborating other predictions of the theory, e.g., individuals err in the same way even when they make non-numerical verbal estimates, such as that an event is highly improbable.


Descriptors :   *PROBABILITY , CALCULUS , COMPUTER PROGRAMS , ESTIMATES , PREDICTIONS , THEORY


Subject Categories : Statistics and Probability


Distribution Statement : APPROVED FOR PUBLIC RELEASE