The concept of personality is a broad one. The personality theorist has an interest in what individual human beings think, feel and do including how the social situation affects and is affected by the individual. Personality theory is concerned not only with differences between individuals, but also with the basic processes of adaptation through which people interact with the conditions of their lives.
The development of personality has long been an area of extreme interest to psychologists and psychoanalysts alike. Because of this, many different theories of personality have developed over the years. From Sigmund Freud to B.F. Skinner, everyone seems to have not only an opinion of what personality is and how it develops but also an idea as to what is the best way to measure and report their findings. In order to test their theories, it was necessary to formulate methods of research that were effective, ethical and would provide a solid foundation for future personality research.