Robert Yerkes created the Army Alpha and Beta tests to measure intelligence.
Psychological Corporation created the first psychological test development company, allowing testing to take place in offices and clinics.
Wolfgang Kohler published 'The Mentality of Apes'
Anna Freud published her first book about her father's ideas on the treatment of children
Jean Piaget published 'The Moral Judgment of children'
Walter B. Cannon coined the term homeostasis and began research on the fight or flight phenomenon.
Henry Murray published the Thematic Apperception Test.
Wechsler-Bellevue Intelligence Test was published.
The Canadian Psychological Associated was founded.
Jean Piaget published 'Psychology of Intelligence' discussing his theories of cognitive development.
Karen Horney published her feministic views of psychoanalytic theory, marking the beginning of feminism.
The Diagnostic and Statistical Manual of Mental Disorders (DSM) was published by The American Psychiatric Association marking the beginning of modern mental illness classification.
Chlorpromazine (Thorazine) first used in the treatment of schizophrenia.
Leon Festinger proposed his theory of 'Cognitive Dissonance' and later became an influence figure in Social Psychology.
Alfred Bandura introduced the idea of Observational Learning on the development of personality.
Lawrence Kolberg introduced his ideas for the sequencing of morality development.
Howard Gardner (professor at Harvard University) introduced his theory of multiple intelligence, arguing that intelligence is something to be used to improve lives not to measure and quantify human beings.
Deep Blue, the supercomputer at the time, beats the World's best chess player, Kasparov, marking a milestone in the development of artificial intelligence.
New Mexico becomes the first state to pass legislation allowing licensed psychologists to prescribe psychotropic medication.