The most influential psychologists in history are those of the 20th century, when psychology was still being considered as a new field. Individuals such as B.F. Skinner, Jean Piaget, and Sigmund Freud were the main ones involved at this time in history. All psychologists who were historically involved with this period in time were influential or the field of psychology would not be here without them. Difficult to pin-point just one or two, the major ones are still here with us today through their theories and ideas. Others are Albert Bandura, Hermann Ebbinghaus, Carol Rogers, Abraham Maslow, William James, Carl Jung, and Edward Thorndike.
The "Review of General Psychology" considers the influential ranking of psychologists to be based on three things: frequency of journal citations, introductory textbook citations, and survey responses of the American Psychological Association. To be considered influential, a psychologist should be one of the best thinkers in psychology. The process of eminent psychology involves playing an important role in the history of psychology, in addition to making outstanding contributions to human behavior and its many cultures.
Top of their review list is Burrhus Fredric Skinner (B.F. Skinner), who recently passed away in March 10, 2000, of cancer. Considered one of the most influential of all American psychologists and as a philosopher, he was a radical behaviorist who developed the theory of operant conditioning, a belief that behavior is determined by its consequences, through reinforcements or punishments. He did not consider the mind as separate from the body, but felt thoughts of the mind as private behaviors, which required analyzing in the same manner as public behaviors. What makes his work eminent is that it is still being applied today in the treatment of phobias, enhancing classroom performances, and addictive behavior.
Second highest rank was Jean Piaget, who passed away on September 17, 1980, in Switzerland. As a psychologist, he is well-known for the elaboration of the childhood stages and the area of developmental psychology in children. His main focus was on the "intellectual or cognitive development of children" in addition to the processes of their minds in knowledge progression. His work is considered eminent as it has had an impact on educational fields and child psychology. Other areas of expertise that utilized his theories were the laptop and tablet style computers through the development of the Dynabook programming system.
Sigmund Schlomo Freud is considered one of the highest influential psychologists, as he is the "father of psychoanalysis". Committing suicide in London after he was driven out of Vienna, Austria, due to being a Jew, he is best known for tracing all psychological problems to problems with sexual issues. Some Freudian ideas that are still present today are references to the traditional "psychology couch", talk therapy to deal with psychological issues, and his theories on the human unconscious.