Psychophysical judgment: Wundt's theory revisited

Summary Wundt's psychological interpretation of Weber's and Fechner's laws rests on two main postulates. First, the magnitude of sensory excitation is proportional to the intensity of the stimulus that produces it. Second, in apperception, sensory comparisons and judgments are made according to psychological relationships: Two sensations are just-noticeably different when they fall in a constant psychological ratio. Wundt's theory implies a hierarchical organization, in which sensory-perceptual processes are embedded within higher-level, apperceptive processes. Such an organization is compatible with recent psychophysical research on loudness and with a model that goes toward resolving some controversies in loudness scaling, notably the seeming incompatibility of Stevens's sone scale and Garner's lambda scale.