John Elias Karlin (February 28, 1918 – January 28, 2013) was an industrial psychologist and a pioneer in human factors engineering at Bell Laboratories of AT&T.
He later moved to the United States, earning a PhD from the University of Chicago and studying electrical engineering at the Massachusetts Institute of Technology.
During World War II Karlin conducted research on psychoacoustics for the United States military.
He successfully argued for the foundation of its Human Factors Engineering Department in 1947, and was promoted to directorship of the unit in 1951.
The development of the modern telephone keypad is attributed to research in the 1950s in the department,[1] which was influential in many other applications.