The study of psychology in philosophical context dates back to the ancient civilizations of Egypt, Greece, China, India, and Persia. Historians point to the writings of ancient Greek philosophers, such as Thales, Plato, and Aristotle (esp. De Anima), as the first significant work to be rich in psychology-related thought.  In 1802, French physiologist Pierre Cabanis sketched out the beginnings of physiological psychology with his essay, Rapports du physique et du moral de l’homme (On the relations between the physical and moral aspects of man).
Cabanis interpreted the mind in light of his previous studies of biology, arguing that sensibility and soul are properties of the nervous system. German physician Wilhelm Wundt is known as the “father of experimental psychology,” because he founded the first psychological laboratory, at Leipzig University in 1879.  Wundt focused on breaking down mental processes into the most basic components, starting a school of psychology that is called structuralism.
Edward Titchener was another major structuralist thinker. Functionalism formed as a reaction to the theories of the structuralist school of thought and was heavily influenced by the work of the American philosopher and psychologist William James. In his seminal book, Principles of Psychology, published in 1890, he laid the foundations for many of the questions that psychologists would explore for years to come.
Other major functionalist thinkers included John Dewey and Harvey Carr. Other 19th-century contributors to the field include the German psychologist Hermann Ebbinghaus, a pioneer in the experimental study of memory who discovered the learning and forgetting curve at the University of Berlin; and the Russian-Soviet physiologist Ivan Pavlov, who discovered classical conditioning theory of learning whilst investigating the digestive system of dogs. 9] Starting in the 1950s, the experimental techniques set forth by Wundt, James, Ebbinghaus, and others would be reiterated as experimental psychology became increasingly cognitive—concerned with information and its processing—and, eventually, constituted a part of the wider cognitive science.  In its early years, this development had been seen as a “revolution”, as it both responded to and reacted against strains of thought—including psychodynamics and behaviorism—that had developed in the meantime.