equivalent to the psychophysical function being a power function. This condition was confirmed for just over half the respondents, and the power form was found to be a reasonable approximation for the rest . It has also been questioned, particularly in terms of signal detection theory, whether any given stimulus is actually associated with a particular and absolute perceived intensity; i.e. one that is independent of contextual factors and conditions. Consistent with this, Luce (1990, p. 73) observed that "by introducing contexts such as background noise in loudness judgements, the shape of the magnitude estimation functions certainly deviates sharply from a power function". Indeed, nearly all sensory judgments can be changed by the context in which a stimulus is perceived. See also Perception Sone References Luce, R. D. & Krumhansl, C. (1988) Measurement, scaling, and psychophysics. In R. C. Atkinson, R. J. Herrnstein, G. Lindzey, & R. D. Luce (Eds.) Stevens' Handbook of Experimental Psychology. New York: Wiley. Pp. 1–74. Smelser, N.J., & Baltes, P.B. (2001). International encyclopedia of the social & behavioral sciences. pp. 15105–15106. Amsterdam; New York: Elsevier. . Stevens, S.S. (1975), Geraldine Stevens, editor. Psychophysics: introduction to its perceptual, neural, and social prospects, Transaction Publishers, . Perception Behavioral concepts Power laws Psychophysics Mathematical psychology Psychoacoustics it:Soglia percettiva