Born in Batavia, N.Y., Ryan earned his A.B. (1933) and Ph.D. (1937) degrees in psychology at Cornell and was appointed as an instructor in 1937. He served as chairman of the Department of Psychology from 1953 to 1961, and was named professor emeritus in 1977.
Ryan's early research focused on the psychology of industrial production, including problems of worker efficiency, measurement of fatigue and effort, job evaluation and the psychological problems of accident control.
Working in the field now known as ergonomics, he developed an index of muscular tension to gauge the effect of glare and other disturbances on efficiency and performance. Ryan published his findings in two books, Work and Effort: The Psychology of Production (1947) and Principles of Industrial Psychology (1970), with co-author Patricia Cain Smith, a former student who is now a professor of psychology at Bowling Green State University.
In the early 1950s, Ryan's interests shifted to the field of human motivation, and he conducted experiments in collaboration with Smith to determine the role of intention in learning. His book on the subject, Intentional Behavior: An Approach to Human Motivation, was published in 1970.
At Cornell, he taught psychology classes in human motivation and statistical methods for more than 25 years.
Ryan's interest in statistical methods was passed to his son, Thomas A. Ryan Jr., developer of the widely used statistics software, "Minitab." Also surviving are a daughter, Adelaide Lyon, Canandaigua, N.Y.; a sister, Mary R. Robinette, Seneca Falls; a brother, John S. Ryan, Locust, N.J.; and his wife, Mary Shaw Ryan, State College, Pa.
Arrangements are by Koch Funeral Home, State College. The family asks that memorial contributions be made to the Department of Psychology, Uris Hall.