Edward Thorndike

Edward Lee Thorndike was an American psychologist who worked at Columbia University's Teachers College for most of his career. He studied comparative psychology and how learning happens, developing a theory called connectionism that became a scientific basis for educational psychology. He also tackled practical problems in industry, like creating exams and testing methods for employees.

Thorndike served on the board of the Psychological Corporation and was president of the American Psychological Association in 1912. A 2002 survey ranked him as the ninth-most cited psychologist of the 20th century. His law of effect provided a foundation for reinforcement theory and behavior analysis, shaping empirical laws in behavioral psychology. This work strongly influenced education, especially in classrooms.

Born in Williamsburg, Massachusetts, to Edward R. and Abbie B. Thorndike—his father was a Methodist minister—he grew up in Lowell. He attended the Roxbury Latin School, then Wesleyan University (B.S. 1895), and earned an M.A. at Harvard in 1897. His brothers, Lynn and Ashley, also became scholars: Lynn specialized in medieval history and magic, Ashley in Shakespeare studies. At Harvard, Thorndike worked with William James, studying how animals learn. He later shifted focus to human learning. His PhD, completed in 1898 at Columbia under James McKeen Cattell, is considered a key document in modern comparative psychology. After a brief, unhappy teaching stint at Case Western Reserve's College for Women in 1899, he joined Teachers College as an instructor, staying there for the rest of his career. In 1937, he became the second president of the Psychometric Society.

He married Elizabeth Moulton on August 29, 1900, and they had five children, including Frances, who became a mathematician. Early on, he bought a large tract of land on the Hudson River and encouraged other researchers to settle nearby, forming a colony where he acted as a kind of tribal leader.

Thorndike was a pioneer in behaviorism, learning research, and using animals in experiments. His doctoral dissertation, "Animal Intelligence: An Experimental Study of the Associative Processes in Animals," was the first psychology study with nonhuman subjects. He wanted to know if animals could learn by imitation or observation. To test this, he built puzzle boxes—about 20 inches long, 15 inches wide, and 12 inches tall—with a door opened by a weight and pulley system when an animal pressed a lever or button inside. He measured how long it took animals, mostly cats, to escape. At first, they wandered and meowed, but eventually they stepped on the switch by chance. After that, they escaped faster in each trial. Watching other animals escape didn't help them learn faster, nor did having their paws placed on the correct levers. This led Thorndike to a trial-and-error explanation of learning. He graphed the escape times, producing a learning curve that showed animals improved quickly at first, then leveled off. The curve also suggested different species learned similarly but at different speeds. These experiments formed the basis of his learning theory.