1837 — The claims of an early mesmerist, Charles Poyen, were examined by a group of "professional men" in New England. Poyen demonstrated various effects of animal magnetism after placing a young woman, Cynthia Ann Gleason, in a somnambulic trance state. Some of Poyen's critics were convinced by the demonstration and became believers in mesmerism. Poyen and Gleason went on to conduct a popular series of public lectures and demonstrations in New England and New York.
1853 — The Pennsylvania Training School for the Feebleminded, the third American institution of its kind, was founded. The school was incorporated on April 7, 1853, but not opened until 1855 in Germantown. James B. Richards was the first principal. The school has since moved to Elwyn and is known as the Elwyn Training School.
1916 — Louis Guttman was born. Guttman devised a method of attitude scaling, scalogram analysis, derived from the cumulatively ordered preferences of the respondent.
1921 — The trustees of Teachers College, Columbia University, authorized the Institute of Educational Research and appointed Edward L. Thorndike to be research director of the division of educational psychology.
1933 — In an article in Science, Edward L. Thorndike offered the evidence of spread of effect as proof of the law of effect. In 1941, the National Academy of Sciences asked its members to describe their most important contribution. Thorndike cited the spread of effect phenomenon, "proving that the after effect of a mental connection can work back upon the connection to strengthen it."
1964 — Abraham Kaplan's book, The Conduct of Inquiry: Methodology for Behavioral Science, was published. By 1980, Kaplan's book had been cited in over 740 other publications and was featured as a "citation classic" in the journal Current Contents.
1965 — The first classroom trials of Fred Keller's personalized system of instruction began at Arizona State University.
1995 — The first prescription written by a practicing psychologist legally trained to prescribe psychoactive drugs was written by U.S. Navy Commander John L. Sexton, PhD. The prescription was for 30 100 mg tablets of Sertraline, an antidepressant that acts by blocking the reuptake of serotonin.