Lloyd deMause created the field of psychohistory and continues to be extremely influential in it. Other notable psychohistorians include Alice Miller and Julian Jaynes, though they are rarely thought of as such.
The center for psychohistorical research is The Institute for Psychohistory which has 19 branches around the globe and has for 30 years published The Journal of Psychohistory.
The director of the Institute is Lloyd deMause, the founding president of the International Psychohistorical Association, whose annual convention is held in New York City in June of every year. His work is used in most college courses in psychohistory.
Psychohistory was also the name of a fictional science in Isaac Asimov's Foundation Trilogy universe, which combined history, psychology and mathematical statistics to create a (nearly) exact science of the behavior of very large populations of people, such as the Galactic Empire. Asimov used the analogy of a gas, where whilst the motion of a single molecule is very difficult to predict, the mass behavior of the gas can be predicted to a high level of accuracy. This concept he then applied to the population of the fictional Galactic Empire, which numbered in the quadrillions. The character responsible for the science's creation, Hari Seldon, established two postulates: that the population whose behaviour was modeled should be sufficiently large and that they should remain in ignorance of the results of the application of psychohistorical analyses.