ABSTRACT
Psychophysical functions relate the subjective magnitude, S, to the physical magnitude, /. They indicate, for example , how loudness increases with auditory intensity. For loudness, like other unidimensional, prothetic modalities , several alternative psychophysical functions are available ( Gescheider, 1988; Marks, 1974a , 1974b; McKenna, 1985; Stevens , 1975). However, Krueger (1989) showed that , for a given modality or condition, the four major types of subjective scales-magnitude, partition or category, summated just noticeable difference (jnd), neurelectric-converge ''when adjustments are made to remove evident sources of error or bias in the magnitude scale (Stevens), the category scale is properly corrected , and the summated jnd scale is not constrained by Weber's law (Fechner) .... The convergence indicates that sensations are phenomenally experie-nced [i.e., introspectable via direct magnitude estimation and category ratings] and also are discernible via indirect procedures [summated jnd . neurelectric ]" (pp . 251-252). Furthermore , "the convergence of the neurelectric scale with the other three types of scales indicates that there is no additional nonlinear transformation beyond that of the peripheral sensory transducers" (p. 252).
