---
title: "History of psychology"
chunk: 1/15
source: "https://en.wikipedia.org/wiki/History_of_psychology"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:00:20.149396+00:00"
instance: "kb-cron"
---

Psychology is defined as "the scientific study of behavior and mental processes". Philosophical interest in the human mind and behavior dates back to the ancient civilizations of Egypt, Persia, Greece, China, and India.
Psychology as a field of experimental study began in 1854 in the German city of Leipzig, when Gustav Fechner created the first theory of how judgments about sensory experiences are made and how to experiment on them. Fechner's theory, recognized today as Signal Detection Theory, foreshadowed the development of statistical theories of comparative judgment and thousands of experiments based on his ideas (Link, S. W. Psychological Science, 1995). In 1879, Wilhelm Wundt founded the first psychological laboratory dedicated exclusively to psychological research in Leipzig, Germany. Wundt was also the first person to refer to himself as a psychologist. A notable precursor to Wundt was Ferdinand Ueberwasser (1752–1812), who designated himself Professor of Empirical Psychology and Logic in 1783 and gave lectures on empirical psychology at the Old University of Münster, Germany. Other important early contributors to the field include Hermann Ebbinghaus (a pioneer in the study of memory), William James (the American father of pragmatism), and Ivan Pavlov (who developed the procedures associated with classical conditioning).
Soon after the development of experimental psychology, various kinds of applied psychology appeared. G. Stanley Hall brought scientific pedagogy to the United States from Germany in the early 1880s. John Dewey's educational theory of the 1890s was another example. Also in the 1890s, Hugo Münsterberg began writing about the application of psychology to industry, law, and other fields. Lightner Witmer established the first psychological clinic in the 1890s. James McKeen Cattell adapted Francis Galton's anthropometric methods to generate the first program of mental testing in the 1890s. In Vienna, meanwhile, Sigmund Freud independently developed an approach to the study of the mind called psychoanalysis, which became a highly influential theory in psychology.
The 20th century saw a reaction to Edward Titchener's critique of Wundt's empiricism. This contributed to the formulation of behaviorism by John B. Watson, which was popularized by B. F. Skinner through operant conditioning. Behaviorism proposed emphasizing the study of overt behavior, because it could be quantified and easily measured. Early behaviorists considered the study of the mind too vague for productive scientific study. However, Skinner and his colleagues did study thinking as a form of covert behavior to which they could apply the same principles as overt behavior.
The final decades of the 20th century saw the rise of cognitive science, an interdisciplinary approach to studying the human mind. Cognitive science again considers the mind as a subject for investigation, using the tools of cognitive psychology, linguistics, computer science, philosophy, behaviorism, and neurobiology. This form of investigation has proposed that a wide understanding of the human mind is possible, and that such an understanding may be applied to other research domains, such as artificial intelligence.
There are conceptual divisions of psychology in "forces" or "waves", based on its schools and historical trends. This terminology was popularized among the psychologists to differentiate a growing humanism in therapeutic practice from the 1930s onwards, called the "third force", in response to the deterministic tendencies of Watson's behaviourism and Freud's psychoanalysis. Proponents of Humanistic psychology included Carl Rogers, Abraham Maslow, Gordon Allport, Erich Fromm, and Rollo May. Their humanistic concepts are also related to existential psychology, Viktor Frankl's logotherapy, positive psychology (which has Martin Seligman as one of the leading proponents), C. R. Cloninger's approach to well-being and character development, as well as to transpersonal psychology, incorporating such concepts as spirituality, self-transcendence, self-realization, self-actualization, and mindfulness. In cognitive behavioral psychotherapy, similar terms have also been incorporated, by which "first wave" is considered the initial behavioral therapy; a "second wave", Albert Ellis's cognitive therapy; and a "third wave", with the acceptance and commitment therapy, which emphasizes one's pursuit of values, methods of self-awareness, acceptance and psychological flexibility, instead of challenging negative thought schemes. A "fourth wave" would be the one that incorporates transpersonal concepts and positive flourishing, in a way criticized by some researchers for its heterogeneity and theoretical direction dependent on the therapist's view. A "fifth wave" has now been proposed by a group of researchers seeking to integrate earlier concepts into a unifying theory.

== Early psychological thought ==