The difference betweem psychoanalysis and psychophysics is that psychoanalysis is a therapeutic practice founded by Sigmund Freud at the end of the 19th century, which consists of a method of research and therapeutic treatment of some mental illnesses from the understanding of behavior, feelings and ways of thinking of the patient. The psychoanalyst is the professional person, wheter psychologist or psychiatrist, who practices psychoanalysis through the analysis of the patient s unconscious through the method of free association, interpretation of dreams and failed actions.
Psychophysics is the discipline that aims to study the relationships between the magnitude of what physical stimuli are and the intensity of the sensations they produce. Psychophysics, from its origins with Weber and Fechner, has been concerned primarily with the quantification of sensation. To the extent that experimental techniques are used for the performance of this task and the discovered laws are expressed in a mathematical language, it is usual to consider psychophysics as the most scientific part of psychology.