Notable for his key role in the development of the psychological theory of functionalism, Carr taught for many years at the University of Chicago and briefly headed the American Psychological Association. He is particularly remembered for his famous "kerplunk experiment," which used rats as subjects.
After earning his bachelor's and master's degrees in psychology from the University of Colorado, he held high school teaching positions in Texas, New York, and Michigan. He later returned to school, completing his doctorate in psychology at the University of Chicago.
His book Psychology: A Study of Mental Activity became the defining text of the functionalism movement.
He was raised on a farm in Indiana.
He and John Dewey were both important theorists of the functionalist school of psychology.