Psychohistory is the study of the psychological motivations of historical events. It attempts to combine the insights of psychotherapy with the research methodology of the social sciences to understand the emotional origin of the social and political behavior of groups and nations, past and present. Its subject matter is childhood and the family, and psychological studies of anthropology and ethnology.
Psychohistory derives many of its concepts from areas that are perceived to be ignored by conventional historians and anthropologists as shaping factors of human history, in particular, the effects of parenting practice and child abuse. According to conventional historians "the science of culture is independent of the laws of biology and psychology". and "[t]he determining cause of a social fact should be sought among social facts preceding and not among the states of individual consciousness".
Psychohistorians, on the other hand, suggest that social behavior such as crime and war may be a self-destructive re-enactment of earlier abuse and neglect; that unconscious flashbacks to early fears and destructive parenting could dominate individual and social behavior.
Psychohistory is a fictional science in Isaac Asimov's Foundation universe which combines history, sociology, and mathematical statistics to make general predictions about the future behavior of very large groups of people, such as the Galactic Empire. It was first introduced in the three short stories (1942–1944) which would later be collected as the 1951 novel Foundation.
Psychohistory depends on the idea that, while one cannot foresee the actions of a particular individual, the laws of statistics as applied to large groups of people could predict the general flow of future events. Asimov used the analogy of a gas: an observer has great difficulty in predicting the motion of a single molecule in a gas, but can predict the mass action of the gas to a high level of accuracy. (Physicists know this as the Kinetic theory). Asimov applied this concept to the population of his fictional Galactic Empire, which numbered a quintillion. The character responsible for the science's creation, Hari Seldon, established two axioms: