Ernst Heinrich Weber (1795–1878) and Gustav Theodor Fechner (1801–1887) attempt to measure the mathematical relationships between the physical magnitudes of external stimuli and the psychological intensities of the resulting sensations,
Hermann von Helmholtz (1821–1894) conducted studies of a wide range of topics that would later be of interest to psychologists –the speed of neural transmission, the natures of sound and color, and of our perceptions of them, etc,
Sir Francis Galton FRS (16 February 1822 – 17 January 1911), cousin of Sir Douglas Galton, half-cousin of Charles Darwin, was an English Victorian polymath, anthropologist, eugenicist, tropical explorer, geographer, inventor, meteorologist, proto-geneticist, psychometrician, and statistician,
Pierre Paul Broca (1824–1880) and Carl Wernicke (1848–1905) identified areas of the brain responsible for different aspects of language,
Wilhelm Maximilian Wundt (16 August 1832 – 31 August 1920), father of experimental psychology,
Gustav Fritsch (1837–1927), Eduard Hitzig (1839–1907), and David Ferrier (1843–1924) localized sensory and motor areas of the brain,
William James (January 11, 1842 – August 26, 1910), educational psychology,
Experimental psychology laboratories were soon also established at Berlin by Carl Stumpf (1848–1936) and at Göttingen by Georg Elias Müller (1850–1934),
Another major German experimental psychologist of the era, though he did not direct his own research institute, was Hermann Ebbinghaus (1850–1909),
Sigmund Freud, born Sigismund Schlomo Freud (6 May 1856 – 23 September 1939), was an Austrian neurologist who founded the psychoanalytic school of psychiatry,
James McKeen Cattell (May 25, 1860 – January 20, 1944), American psychologist
James Mark Baldwin (January 12, 1861 – November 8, 1934). He made important contributions to early psychology, psychiatry, and to the theory of evolution.
George Herbert Mead (February 27, 1863 – April 26, 1931). He is regarded as one of the founders of social psychology and the American sociological tradition in general.
Edward Bradford Titchener, D.Sc., Ph.D., LL.D., Litt.D. (January 11, 1867 – August 3, 1927), structuralism,
Margaret Floy Washburn (July 25, 1871 – October 29, 1939), animal behavior and motor theory. She was the first woman to be granted a PhD in psychology (1894).