The limits of perceived magnitude: Comparison among individuals and among perceptual continua

Two models of perceived magnitude that focus on the concept of dynamic range (DR) for sensory systems are summarized and compared. The first asserts that, whereas the size of DR varies physically from one perceptual continuum to another, all are subjectively equal. The other asserts that, for any given continuum, whereas the size of DR varies over individual observers, the subjective range does not.A test of the second model is reported for perceived effort for a range of loads on a bicycle ergometer. Both DR and judgmental (magnitude estimation) range estimates were obtained for 30 subjects. The former exhibited the expected variability over subjects, but there was no support for the predicted invariance of the latter. However, it is concluded, first, that the finding constitutes disconfirming evidence for the second model only if it is assumed that magnitude estimates are proportional to perceived magnitude, an issue which itself remains in dispute, and second, that the testability of the second model is doubtful unless a measure can be identified that is a stateable function of perceived magnitude.