Measuring subjective probabilities by the magnitude production method

The magnitude production method was employed to determine how subjective probability estimates are formulated. Subjects assessed the subjective probabilities of different uncertain events by providing two responses: a verbal numerical estimate and a corresponding exerted force on a handgrip. The subjects' responses were related by an ogival function. This function differed significantly from a power function that is frequently found in magnitude production studies and that was also obtained for the control group in the present study. Further implications of the ways people estimate subjective probabilities and the possible utilization of psychophysical methods for the study of subjective probability are discussed.