Decisions Based on Numerically and Verbally Expressed Uncertainties

• Published in: Journal of experimental psychology. Human perception and performance 1988-05, Vol.14 (2), p.281-294
• Main Authors: Budescu, David V, Weinberg, Shalva, Wallsten, Thomas S
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Decision Making; Fundamental and applied biological sciences. Psychology; Gambling; Human; Miscellaneous; Numbers (Numerals); Perception; Probability Judgment; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Stimulus Presentation Methods; Words (Phonetic Units)
• ISSN: 0096-1523; 1939-1277
• DOI: 10.1037/0096-1523.14.2.281

A two-stage within subjects design was used to compare decisions based on numerically and verbally expressed probabilities. In Stage 1, subjects determined approximate equivalences between vague probability expressions, numerical probabilities, and graphical displays. Subsequently, in Stage 2 they bid for (Experiment 1) or rated (Experiment 2) gambles based on the previously equated verbal, numerical, and graphical descriptors. In Stage 1, numerical and verbal judgments were reliable, internally consistent, and monotonically related to the displayed probabilities. However, the numerical judgments were significantly superior in all respects because they were much less variable within and between subjects. In Stage 2, response times, bids, and ratings were inconsistent with both of two opposing sets of predictions, one assuming that imprecise gambles will be avoided and the other that verbal probabilities will be preferred. The entire pattern of results is explained by means of a general model of decision making with vague probabilities which assumes that in the present task, when presented with a vague probability word, people focus on an implied probability interval and sample values within it to resolve the vagueness prior to forming a bid or a rating.