Psychophysics is the scientific study of the relation between stimulus and sensation, and therefore the problems of psychophysics constitute some of the most fundamental problems of modern psychology. For centuries thinkers have recognized the importance of understanding sensation. In fact, experimental psychology developed as an independent science largely because of the recognition that the scientific study of sensation could yield insight into the workings of the human mind.
Experimental psychology was established as an independent science when, in Leipzig, 1879, Wilhelm Wundt founded the first laboratory for experimental work exclusively directed toward understanding psychological processes. The work of Wundt and other early experimental psychologists evolved from the British empiricist and associationist schools of philosophy, which had firmly established the idea of the senses as the key to human understanding. This idea was reinforced by advances in sensory physiology, which suggested that the problem might yield to scientific investigation.
But perhaps the single most important historical antecedent of experimental psychology was psychophysics. Thus, for some psychologists the most significant date in psychology is not 1879, the founding date of Wundt's laboratory, but 1860, the date of the publication of Fechner Elements of Psychophysics. Fechner's work, in providing methods and theory for the measurement of sensation, gave psychology basic tools for the study of mind.
Today psychophysics remains a central part of experimental psychology. Important recent changes in psychophysics are the development of the theory of signal detection and the refinements of methods for directly scaling sensory magnitude. These two advances have greatly broadened the applicability of psychophysics to areas far beyond the original problems of measuring sensory thresholds. Modern psychophysics can be credited with contributions to the solution of problems in such diverse realms as sensory processes, memory, learning, social behavior, and esthetics.