Elements of Psychophysics

Gustav Fechner, a German physicist and philosopher, is credited with founding psychophysics, the scientific study of the quantitative relationship between sensations and the stimuli that produce them. Fechner's seminal work, Elements of Psychophysics (1860), laid the groundwork for experimental psychology.12

He proposed that mind and body are two aspects of the same reality and developed experimental methods to measure sensations in relation to the physical magnitude of stimuli. A key concept is Weber's law, which states that the change in a stimulus needed to produce a just-noticeable sensation is proportional to the original stimulus. Fechner's work provided a way to quantitatively measure sensation, enabling the development of a scientific, quantitative psychology. Psychophysical methods are still used today in sensation studies and practical applications like product testing.123