Robert Sessions Woodworth (October 17, 1869 – July 4, 1962) was an American psychologist and the creator of the personality test which bears his name.

[1][2] A Review of General Psychology survey, published in 2002, ranked Woodworth as the 88th most cited psychologist of the 20th century, tied with John Garcia, James J. Gibson, David Rumelhart, Louis Leon Thurstone, and Margaret Floy Washburn.

During his senior year, Woodworth took a class in psychology by Charles Edward Garman, which caused him to change his future plans.

In 1895, he returned to college as an undergraduate student at Harvard University, studying philosophy with Josiah Royce, psychology with William James, and history with George Santayana.

James McKeen Cattell offered Woodworth a graduate fellowship at Columbia University, one of the two primary functionalist schools in psychology.

Woodworth and Thorndike empirically studied the benefits of a disciplinary education along with transfer of training and found no effect.

[8] Woodworth emphasized that that labeling is based on alleged differences both internal (mental function and size) and external (skin color), making it difficult to compare them empirically.

With the onset of World War I, APA asked Woodworth to assist them in trying to prevent what was then known as "shell shock".

This tolerant, open-minded view was likely a result of his unique perspective of psychology, being part of the subject for nearly the entire fifty years of its existence.

In 1914, Woodworth was elected president of APA, and in his presidential address, he discussed the question of the existence of imageless thoughts.

Within his modified S-O-R formula, Woodworth noted that the stimulus elicits a different effect or response depending on the state of the organism.

Woodworth advocated the creation of a technical vocabulary for psychology rather than only relying on often subjective operational definitions, but he was ignored by the community.

He conveniently ignores the fact that he held very important and influential positions, such as being chairman of the National Research Council's Division of Anthropology and Psychology, in his autobiography.

More recently the theory has been extended to theorize that artificial organisms (AI-enabled systems) can also elicit responses.