German psychologists

Hans Wallach (November 28, 1904 – February 5, 1998) was a German-American experimental psychologist whose research focused on perception and learning. Although he was trained in the Gestalt psychology tradition, much of his later work explored the adaptability of perceptual systems based on the perceiver's experience, whereas most Gestalt theorists emphasized inherent qualities of stimuli and downplayed the role of experience. Wallach's studies of achromatic surface color laid the groundwork for subsequent theories of lightness constancy, and his work on sound localization elucidated the perceptual processing that underlies stereophonic sound. He was a member of the National Academy of Sciences, a Guggenheim Fellow, and recipient of the Howard Crosby Warren Medal of the Society of Experimental Psychologists.

Erich Neumann (Hebrew: אריך נוימן; 23 January 1905 – 5 November 1960) was a German psychologist, philosopher, writer, and student of Carl Jung.

Catherine Brieger Stern (1894–1973) was a German psychologist and educator. Born under the name Käthe Brieger, she developed sets of mathematical manipulatives similar to Cuisenaire rods for children to use in building up their number sense and knowledge of arithmetic. Her book, Children Discover Arithmetic (1949) was used by others to work on the problems that children face when learning arithmetic.In 1938, she emigrated to the United States. From 1940 to 1943, she was a research assistant to Max Wertheimer at the New School for Social Research.

David Katz (1 October 1884, Kassel – 2 February 1953, Stockholm) was a German-born Swedish psychologist and educator who specialized in Gestalt psychology and phenomenology. He was a professor Emeritus at the University of Stockholm. Prior to the establishment of the Nazi regime in Germany, he served as the chair of psychology and education at the State University of Mecklenburg in Rostock.

Kurt Koffka (March 12, 1886 – November 22, 1941) was a German psychologist and professor. He was born and educated in Berlin, Germany; he died in Northampton, Massachusetts, from coronary thrombosis. He was influenced by his maternal uncle, a biologist, to pursue science. He had many interests including visual perception, brain damage, sound localization, developmental psychology, and experimental psychology. He worked alongside Max Wertheimer and Wolfgang Köhler to develop Gestalt psychology. Koffka had several publications including "The Growth of the Mind: An Introduction to Child Psychology" (1924) and "The Principles of Gestalt Psychology" (1935) which elaborated on his research.

Erwin Walter Maximilian Straus (11 November 1891, Frankfurt am Main – 20 May 1975, Lexington, Kentucky) was a German-American phenomenologist and neurologist who helped to pioneer anthropological medicine and psychiatry, a holistic approach to medicine that is critical of mechanistic and reductionistic approaches to understanding and treating human beings.
Some of his work can also be regarded as a precursor to or early version of neurophenomenology. Straus taught at Black Mountain College.
His books published in English include:

Phenomenology: Pure and Applied (1964, Duquesne University Press)
Phenomenological Psychology (1966, Basic Books)
Psychiatry and Philosophy (1969, Springer)
Phenomenology of Memory (1970, Duquesne University Press)
Language and Language Disturbances (1974, Duquesne University Press)
Man, Time, and World: Two Contributions to Anthropological Psychology (1982, Humanities Press)
On Obsession: A Clinical and Methodological Study (1987, Johnson Reprint Corp)

Gustav Richard Heyer (29 April 1890 – 19 November 1967) was a Jungian psychologist, "the first significant person in Germany to be attracted to Jung's psychology".

Gerhard Adler (14 April 1904 – 23 December 1988) was a major figure in the world of analytical psychology, known for his translation into English from the original German and editorial work on the Collected Works of Carl Gustav Jung. He also edited C.G. Jung Letters, with Aniela Jaffe. With his wife Hella, he was a founding member of the Society of Analytical Psychology in London, of which C.G. Jung was first President. Despite their years-long collaboration on translating and editing, Adler's allegiance to Jung and the "Zurich school" caused irreconcilable differences with Michael Fordham, and led to his leaving the Society of Analytical Psychology and founding the Association of Jungian Analysts.

Ruth Charlotte Cohn (born 27 August 1912 in Berlin, died 30 January 2010 in Düsseldorf) was a psychotherapist, educator, and poet. She is best known as the creator of a method for learning in groups called theme-centered interaction (TCI). She was the founder of the Workshop Institute for Living Learning (WILL), which is known today as the Ruth Cohn Institute for TCI.

Franz Carl Müller-Lyer, born Francis Xavier Hermann Müller (5 February 1857 - 29 October 1916) was a German psychologist and sociologist. The Müller-Lyer illusion is named after him.