Probabilistic Reasoning

Tufts University, Medford MA

Investigators

Abstract

Everybody thinks probabilistically, whether knowingly or not. Inability to reason well probabilistically makes one prone to a variety of irrational fears and vulnerable to scams designed to exploit probabilistic naivete, precludes intelligent assessment of risks, ensures the operation of several common biases, impairs decision making under uncertainty, facilitates the misinterpretation of statistical information, precludes critical evaluation of likelihood claims, and generally undercuts rational thinking in numerous ways. A large literature appears to support the view that people's intuitions about matters of probability are largely wrong. This view may be correct, but many of the results that have been interpreted as supportive of it can be challenged on methodological grounds. In particular, instructions to participants in studies of probabilistic reasoning have often been ambiguous or incompletely stated. In this study, we plan to manipulate the degree of ambiguity and incompleteness of problem statements in a controlled fashion with the objective of determining the extent to which previous results suggesting incorrect intuitions about probability will be obtained with problem statements that are unambiguous and complete.