ABSTRACT
The theory of relative judgment is based upon sequential comparisons between a presented stimulus and a mental psychophysical standard. The process of comparison continues until either of two response thresholds is first exceeded; then a response is emitted. This sequential theory of judgment provides predictions for both response probability (RP) and response time (RT), and a fundamental relationship between RP and RT. The application of the theory to the psychometric function rests on the assumption that a single mental standard, not necessarily identical to the experimenter’s standard, provides the referent against which individual stimuli are compared. To confirm the predicted relation between RP and RT, three experiments are examined. In all cases the theoretically predicted relationship is supported by the data. As a bonus, it is now possible to estimate the expected value of the mental standard from either RP or RT results, compare the estimates, and relate the estimated value to units of the physical stimulus.
