n.
Branch of psychology concerned with the effect of physical stimuli (such as sound waves) on mental processes.
Psychophysics was established by Gustav Theodor Fechner in the mid-19th century, and since then its central inquiry has remained the quantitative relation between stimulus and sensation . A key tenet has been Weber's law . Psychophysical methods are used today in vision research and audiology, psychological testing , and commercial product comparisons (e.g., tobacco, perfume, and liquor).