APA Dictionary of Psychology

a mathematical relationship between the strength of a physical stimulus and the intensity of the sensation experienced. Psychophysical laws were first developed from the empirical research conducted by Ernst Heinrich Weber and Gustav Theodor Fechner, chiefly at the University of Leipzig. This work, aimed at direct scientific investigation of the mind–body problem, established the foundation of psychology as an experimental science. Also called psychophysical relationship. See also inner psychophysics; outer psychophysics.