2nd century BCE Galen classifies human temperament according to the four humors.
1890 In Principles of Psychology, William James makes an early attempt to define the self as having both an “I” (the knowing self) and a “me” (the experiencing self).
1946 Raymond Cattell develops his 16PF (Personality Factors) questionnaire, based on Allport and Odbert’s lexical hypothesis.
1970s Hans J. Eysenck creates the PEN (Psychoticism, Extraversion, Neurotisicm) personality questionnaire.
1993 American psychologist Dan P. McAdam demonstrates the idiographic method in his book The Stories We Live By.
Gordon Allport is sometimes ...