• University of Nebraska, B.A., M.A. (1917-1918, 1919-1924)
  • Cornell University, Ph.D. (1924-1927)


  • Teacher Grades 1 through 8 outside Phillips, Nebraska (1915-1916)
  • Teacher Grades 5 through 8 Phillips, Nebraska (1916-1917)
  • U. S. Army Private (1918-1919)
  • Teacher Grades 7 and 8 Hooper, Nebraska (Spring 1919)
  • Acting Superintendent of Schools (Summer 1919)
  • Interim Director for University of Nebraska Psychological Clinic (1919-1921)
  • Instructor at University of Illinois (1926-1927)
  • Assistant Professor at University of Kansas (1927-1928)
  • Associate Professor at University of Nebraska (1928-1932)
  • Professor at University of Nebraska (1932-1940)
  • Director of the Bureau of Instructional Research (1938-1940)
  • Teacher at the University of Southern California (Summer 1938, 1939)
  • Professor at University of South California (1940-1967)
  • Director of Psychological Research #3 Santa Ana Army Air Base (1942-1946)
  • President or member of numerous organizations and societies
  • Editorial board member for scholarly journals such as the American Journal of Psychology and Psychological Review

Definition of Intelligence

A systematic collection of abilities or functions for the processing of information of different kinds in various ways.


  • Experimental Psychology including attention and visual perception, learning and memory, and experimental esthetics
  • Statistical Psychology with regard to test theory and evaluation, factor analysis, psychophysics, and scaling
  • Mental abilities including knowledge gained from factor analytic studies, and the theoretical model of the structure of intellect
  • Personality theory and measurement
  • Author/co-author of over 25 books, 30 tests, and 300 journal articles

Ideas & Interests

During Guilford’s time as interim director of the Psychology Clinic, he became interested in the dissimilarities of children’s abilities in different areas. He came to believe intelligence was not one monolithic, global attribute but a combination of multiple abilities. This is what was to be the dominant focus of his professional career—individual differences. Guilford believed there were many relatively independent mental abilities factors. With WWII, Guilford was able to apply his factor analytic methodology to study these mental abilities. Because of his research on U.S. Army Air Corps during the war, he and his collaborators were able to identify and measure twenty-five important mental ability factors.

Further, Guilford believed societies quest for easily objectifiable testing and scoring had directed away from measuring important qualities that individuals posses. Operationally, intelligence was defined as the ability to read, compute mathematically, and perform other similar subjects. According to Guilford, these types of intelligence tests revealed little about a person’s creative nature. After researching available intelligence tests, he determined many do not intercorrelate perfectly because each test emphasized a different primary ability. Guilford concluded individuals differ in a continuous manner for each primary ability.

By the 1950’s, Guilford felt there needed to be a system developed to classify the new mental abilities being discovered. Traditional models prior to Guilford proposed a single universal ability at the top of a hierarchal pattern. In 1955, the first version of the Structure of Intellect (SI) model was presented. This model became Guilford’s main focus of research. The SI model includes a Content dimension, Products dimension, and Operations dimension. It is represented as a cube with each of the three dimensions occupying one side. Each ability is defined by a conjunction of the three categories, occupying one cell in the three-dimensional figure. There are five categories of Content including visual, auditory, symbolic, semantic, and behavioral. Six categories exist in the Products dimension including units, classes, relations, systems, transformation, and implications. The five kinds of Operations include cognition, memory, divergent production, convergent production, and evaluation. Guilford’s SI Theory is an open system such that it allows for newly discovered categories to be added in any of three directions. Many of the abilities are believed to be correlated with each other. The 5 x 6 x 5 figure provides at least 150 possible abilities, with over 100 having been empirically verified. The model also suggests where new abilities may be discovered based on existing abilities. Because of Guilford’s contributions during his career, intelligence was shown to be incredibly complex. No longer was intelligence a monolithic global trait considered innate and absolute.

Notable Publications

  • Psychometric Methods (1936)
  • Fundamental Statistics in Psychology and Education (1942)
  • Printed Classification Tests (1947)
  • General Psychology (1939)
  • Fields of Psychology (1940)
  • Personality (1959)
  • Prediction of Categories from Measurements (1949)


Guilford, J. P. (1950) Creativity. The American Psychologist, 5,444-454.

Michael, W. B., Comrey, A. L., & Fruchter, B. (1963). J. P. Guilford: Psychologist and teacher. Psychological Bulletin, 60, 1-34.

Guilford, J.P. (1982). Cognitive psychology’s ambiguities: Some suggested remedies. Psychological Review, 89, 48-59.

Guilford, J.P. (1967). The Nature of Human Intelligence. New York: McGraw-Hill.

Comrey, A. L. (1993). Joy Paul Guilford 1897-1987 (pp. 199-210).  In Biographical Memoirs V. 62. National Academy of Sciences: Washington, D.C.