Psychophysical law or Weber-Fechner Law (Weber-Fechner Law) is an empirical rule that establishes a proportional relationship between the intensity of the stimulus (stimulus dimensions) and the strength of sensation. A simple formula describing this relationship is:
S = k * I, where s is the magnitude of the sensation, i is the intensity of the stimulus, and k is some constant value, the numerical value of which may differ for different modalities (for example, we know that for the visual modality the parameter k is much higher than for the auditory ).
The law of psychophysics is also called the “Law of Perception” rule: in classical psychology it was customary to distinguish between the concepts of sensation and perception. These two psychological concepts are included in one behavioral act, while sensations have a “place” only in the internal activity of the subject and are identified with the simplest forms of reflection of the external world. Psychophysical laws are studied in order to answer questions like “what is the physical mechanism of perception?”