Leipzig 1854: Fechner’s experiments launch a science
Psychology, the science of behavior and mental processes, had philosophical roots in Egypt, Persia, Greece, China, and India. Experimental study began in 1854 Leipzig when Gustav Fechner theorised sensory judgments—today’s Signal Detection Theory ancestor—before Hall, Dewey, and Münsterberg applied the lab abroad.
Behaviorism under Watson and Skinner answered Titchener’s debates by measuring overt acts. Late twentieth-century cognitive science reopened the black box with linguistics, computing, and neuroscience tools.
Therapeutic third-force humanism from the 1930s pushed against deterministic waves, a branding still used to periodise schools.
Long before laboratories, cultures speculated about mind, soul and brain. In Egypt, the Edwin Smith Papyrus offers one of the first known accounts of the brain, with guesses about what it does. Greek thinkers from Thales onward built an elaborate theory of the psyche, and Plato's three-part soul and chariot allegory shaped Western thinking so deeply that psychoanalysts later saw his ideas as anticipating id, ego and libido. The Stoics and Epicureans turned to the bodily basis of mind, a question the Roman physician Galen handled most influentially. Among the Dead Sea Scrolls, the Manual of Discipline splits human nature into opposing spirits of truth and perversity, and in 2008 Walter Freeman argued that Aquinas's account of cognition fits modern brain dynamics best.
China administered ability tests in its schools for centuries, and texts some 2,500 years old describe mania and psychosis, blamed on imbalance. In the sixth century AD Lin Xie had subjects sketch a circle with one hand while drawing a square with the other, a distraction test sometimes called the first psychology experiment. Indian Vedanta developed a theory of the self wrapped in layers called koshas, and Samkhya philosophy divided the mind into five components, among them manas and ahankara, the sense of I. In the medieval Muslim world, Ahmed ibn Sahl al-Balkhi, who lived from 850 to 934, described disorders of both body and soul, while Avicenna catalogued hallucination, mania, melancholia, dementia and epilepsy.
Source: History of psychology
