magnitude estimationA method of interval scaling in which people are asked to estimate the magnitude of a subjective experience (e.g., perceived sound intensity) by assigning a number to it, in a Likert-like fashion
A psychophysical method of evaluating stimuli above threshold. The subject assigns numbers according to the apparent magnitudes of the stimuli. The results relating the magnitude of sensation S and the stimulus intensity I usually follow a power law (or Stevens' power law), that is S = kIn where k is a constant and n the exponent which depends on the sensory modality. Example: the magnitude perceived brightness of a 5 degrees target viewed by a dark adapted subject follows the relation S = kI0.33, that is, the intensity of the light target needs to be increased some tenfold to see it twice as bright. Syn. direct scaling.