CAREER: Bringing a dynamic, stochastic, and computational, understanding to subjective probabilities

Michigan State University, East Lansing MI

Investigators

Abstract

We rely on the probability judgments of experts and laypeople every day. Space shuttles are launched not only on the basis of weather forecasts, but also on an engineer's subjective opinion that a part will or will not fail. Military missions and political policies are put in place using intelligence analysts' beliefs that an event will occur or has occurred. Without doubt the use of probability judgments to make decisions makes the accuracy of subjective probabilities of utmost importance. Indeed the accuracy of subjective probabilities has been well studied in the cognitive and decision sciences. Yet, an equally valuable aspect of subjective probabilities is the amount of time it takes judges to formulate their estimates. Clearly, the time a judge takes to make a probability judgment has external costs to both the judge and the decision maker. Yet, little is known about the internal time course of subjective probability judgments. Consequently, the impact these external costs have on subjective probabilities and their accuracy is not known. In this project the Principal Investigator pursues research examining how variables external to the judge (e.g., time pressure; rewards and penalties) and internal to the judge (e.g., attention and sequential effects) impact the time course and accuracy of subjective probabilities. A general framework called Judgment Field Theory will integrate how these internal and external variables impact probability judgments. Moreover, the framework offers a cognitive account of how different descriptions of the same event (e.g., Lance Armstrong will win the race vs. Lance Armstrong won?t lose the race) change how judges evaluate the likelihood of an event occurring and how this evaluation changes as a function of time. The broader impacts of the research are three-fold. First, the research will help in the development of methods to evaluate the accuracy of subjective probabilities. These methods can ultimately be used to improve the accuracy of judges. Second, the theoretical framework will be used in the development of an undergraduate psychological methods course curriculum that infuses a traditional methods course with techniques of cognitive modeling. Finally, a broader impact is the outreach to and integration of a diverse group of undergraduate and graduate students into cognitive science at MSU.