The study asked participants to recall and write down information about an event from their childhood in which they became separated from their parent in a crowded shopping mall. What the participants did not know was that this "event" was a fictional scenario designed to appear as a plausible part of their pasts.

Freud was a huge proponent of the unconscious state of mind and believed human beings buried most of their unwanted thoughts and desires there. This concept is the basis for Freudian psychoanalytic theory and principles.

Carl Jung was strongly influenced by Freud's idea of the unconscious mind, and took it one step further into society as a whole. He believed that members of the same species have inborn ideas and images that are common across cultures.

Like John Watson, B. F. Skinner was a Behavioralist. He is best known for developing the theory of operant conditioning as an alternative to Pavlov's classical conditioning.

Erik Erikson believed that psychosocial development follows an eight-stage progression. Each stage consists of two competing paths of development (e.g. trust v. mistrust).

Erikson's eight stages are trust v. mistrust, autonomy v. shame/doubt, initiative v. guilt, industry v. inferiority, identity v. role confusion, intimacy v. isolation, generativity v. stagnation, and integrity v. despair.

Wilhelm Wundt, also known as the "Father of Experimental Psychology", developed the first formal psychology lab at the University of Leipzig in 1879.

Carl Rogers and Abraham Maslow are both associated with the Humanistic (also sometimes called the Client-Centered) approach to psychology, which emphasizes people's underlying desire and need for self-actualization. The humanist approach focuses more on encouraging a holistic view of mental health and self-actualization, as opposed to a problem-focused treatment model. 

In 1882, Charcot established the first neurology clinic at the Salpetriere, an accomplishment for which he is often known as "The Father of Neurology".

Skinner was a key theorist in the development of the behaviorist approach to psychological study. Skinner's particular brand of behaviorism was called Radical Behaviorism, and much of Skinner's research was focused on operant conditioning (conditioning focusing on the modification of voluntary behavior through positive or negative reinforcement and punishment). 

Carl Rogers studied humanistic psychology. Carl Jung and Freud maintained a relationship from 1906-13; a rift developed in their relationship as Jung increasingly deemphasized the role of libido, thus distancing himself from Freud's theoretical framework. Freud and Adler were co-founders of the Vienna Psychoanalytic Society (although Freud would later have Adler expelled from this society over disagreements in their ideas). Karen Horney is widely regarded as a Neo-Freudian thinker, although she differed widely with Freud on many points (most notably the differences in psychology between the sexes).