The field of psychology is one that combines many disciplines. It is one of the few sciences that combine a person’s biology, the human chemistry and other aspects to determine why a person behaves the way they do. Psychologists through the years have brought their individual ideas and theories to the field and have given us several ideas about what affects human behavior and how to understand it better. Here are some of the most famous psychologists that have made contributions to this important field.

Wilhelm Wundt (1832-1920) Nationality: German Known for: A founding father of modern psychology While he is regarded by many as the “father of experimental psychology,” Wundt founded the first formal laboratory at the University of Leipzig dedicated to doing psychological research. He is also credited with being the person who separated the field of psychology from other sciences like philosophy and biology.	William James(1842-1910) Nationality: American Known for: Pragmatic theory of truth His theory of pragmatism stated that it is impossible to prove an idea’s truth. Therefore, it should be evaluated on its usefulness. He also believed in an idea he called “functionalism,” which takes into account an entire event instead of just individual parts of it.	Ivan Pavlov (1849-1936) Nationality: Russian Known for: Developed the concept of the conditioned reflex Known for his “Pavlov’s Dog” experiment, Ivan Pavlov discovered that dogs would begin to salivate when they thought they were going to get food. His findings gained approval among his peers and even in culture as the idea was used in Huxley’s “Brave New World” and other works.
Sigmund Freud (1856-1939) Nationality: Austrian Known for: The father of psychoanalysis Freud was one of the innovators in the field of psychology. He played a major role in the field’s development and many of his ideas are controversial and not widely accepted. He thought that many psychological issues that people have could be traced back to their sexual development.	Alfred Binet (1857-1901) Nationality: French Known for: Invented the Binet-Simon scale The Binet-Simon scale was the first accepted intelligence test used in schools to help determine which students needed extra help with learning the curriculum. The test was based on a variety of tasks created by Binet and Simon that were relevant to a child’s ability at various stages in life.	Alfred Adler (1870-1937) Nationality: Austrian Known for: Founded the school of individual psychology Adler is credited with several concepts in the field of psychology. For one thing, he disagreed with Freud’s idea that a patient and psychologist should face away from each other. He felt they should face each other. He also believed that the personality strives for wholeness and a balance with society.
Carl Jung (1875-1961) Nationality: Swiss Known for: Founder of analytical psychology Carl Jung is known for several things related to the field of psychology, including dream analysis, his theory of the collective unconscious, and the archetype. He also studied the traits of introverts and extroverts. Jung also indirectly helped form Alcoholics Anonymous.	John B. Watson (1878-1958) Nationality: American Known for: Developed the idea of behavior psychology, or behaviorism Watson explored the ideas of how behaviorism affected how children are raised best, advertising strategies, and animal behavior. He is well-known for his “Little Albert” experiment in which he studied the behavior of children to find support for his theory that they react with fear when they hear a loud noise.	Melanie Klein (1882-1960) Nationality: Austrian Known for: Specialized in therapeutic techniques involved in child psychology Klein had an impact on developmental psychology in that she created a “play therapy” idea that is still used with children today. She also placed an emphasis on the relationship between a mother and child and how it affected the development of the child as they grew.
Sabina Spielrein (1885-1942) Nationality: Russian Known for: Helped influence the field of psychoanalysis Spielrein, who was one of the first psychoanalysts to be female, impacted the field with her essay entitled Destruction as the Cause of Coming into Being, which she wrote in 1912. One of her beliefs was that the sexual drive had an aspect of transformation and destruction.	Karen Horney (1885-1952) Nationality: German Known for: Founder of feminist psychology Horney formulated the theory of neurotic needs, which explained that a person’s neurosis was a direct result of the anxiety they have in their personal relationships. The needs she explores fall into three categories – those that move you towards others, away from others, and against others.	Kurt Lewin (1890-1947) Nationality: German-American Known for: Founder of social psychology Lewin was one of the first psychologists to study group dynamics, which explores how people behave and think while they are in a group situation. He also specialized in studying organizational development, which deals with companies and making their organization more efficient and effective.
Fritz Perls (1893-1970) Nationality: German-Jewish Known for: Coined the phrase “Gestalt therapy” Along with is wife, Laura Perls, Fritz developed a form of psychotherapy that came to be known as “Gestalt therapy.” This type of therapy included enhanced perception, bodily feelings, behaviors and emotions. It also emphasized evaluating experiences at the current moment and personal responsibility.	Anna Freud (1895-1982) Nationality: Austrian Known for: Co-founder of psychoanalytic child psychology As Sigmund Freud’s last child, Anna Freud made a name for herself in the field of psychology. She studied psychoanalytic topics like daydreaming, child development and more. She studied how adolescents develop into adulthood and she received great praise for the papers she wrote, specifically “About Losing and Being Lost.”	Jean Piaget (1896-1980) Nationality: Swiss Known for: Formulating the theory of cognitive development Piaget worked closely with children to study their thought processes and how they differed from adults. He also contributed to the field of developmental psychology and many of his theories and ideas are still relevant today.
Lev Vygotsky (1896-1934) Nationality: Soviet Belarusian Known for: Founder of the theory of cultural-historical psychology As a Russian psychologist, much of Vygotsky’s works were criticized and oppressed by the Communists. This left many of his idea inaccessible for the Western world to study. But he was heavily influential in the field of educational psychology and many of his ideas are still being studied today.	Erich Fromm (1900-1980) Nationality: German Known for: Society’s effects on the human psyche Fromm published works that dealt with political psychology and his theory on the human character. His main idea was the freedom most important aspect of human nature. He also categorized three ways that humans use to escape from freedom, including destructiveness, authoritarianism, and automaton conformity.	Jacques Lacan (1901-1981) Nationality: French Known for: Formulated the “mirror stage” of psychoanalysis Lacan’s “mirror stage” is a point in the life of a person’s development in which they are at a turning point. It also signifies a strong relationship with their body image. Lacah is also known for theorizing the “three orders,” which include the imaginary, the symbolic, and the real.
Milton Erickson (1901-1980) Nationality: American Known for: Founder of the American Society for Clinical Hypnosis Erickson specialized in the fields of family therapy and medical hypnosis. He also studied and experimented with trances and the unconscious mind. His work in hypnosis was controversial during his time period and still is today.	Carl Rogers (1902-1987) Nationality: American Known for: Co-founder of the humanistic approach Rogers was interested in the human potential. He based much of his theoretical work on Abraham Maslow, but he added that a person needs certain needs and conditions met, such as empathy and genuineness, before they can actually grow. He also believed that self-actualization must take place in order for a person to reach their full potential.	Erik Erikson (1902-1994) Nationality: German-American Known for: Formulated the theory of psychosocial development Influenced heavily by Freud, Erikson believed in stages of development throughout life. But he put more emphasis on a person’s culture and environment rather than their sexual development in forming the personality. His psychosocial theory included ideas like fostering a sense of identity, trusting others, and more.
B. F. Skinner (1904-1990) Nationality: American Known for: Formulated the idea of radical behaviorism Skinner is known for many things, but his two main ideas are operant conditioning and negative reinforcement. With his research in operant conditioning, he found that behavior depended more on what happened after a response rather than what happened before it. He also published more than 20 books and 200 articles on the topic of psychology.	Viktor Frankl (1905-1997) Nationality: Austrian Known for: Developed the idea of logotherapy Frankl believed that humans are motivated by the search for the meaning of life. He believed that any efforts through psychotherapy should focus on that motivation. He also published Man’s Search for Meaning, which became a major bestseller and told of his life in a German concentration camp.	John Bowlby (1907-1990) Nationality: British Known for: Conducted work in attachment theory The attachment theory idea concerns how humans interact throughout long-term relationships. At the base of this theory is the idea that an infant must develop a relationship with one or more primary caregivers for normal emotional and social development.
Abraham Maslow (1908-1970) Nationality: American Known for: Maslow’s hierarchy of needs One of Maslow’s fundamental theories was that humans are motivated by needs. As a result, their actions are designed with a certain end result in mind. His idea of a hierarchy of needs stated that humans need to fulfill certain needs before they can move on to fulfill another need.	Albert Ellis (1913-2007) Nationality: American Known for: Developed the Rational Emotive Behavior Therapy Ellis is one of the main pioneers in the cognitive revolutionary paradigm shift in th field of psychotherapy. He also founded the cognitive-behavioral therapies, which is a therapeutic approach that deals with dysfunctional behaviors and emotions with goal-oriented procedures. He is also considered one of the top three influential psychotherapists ever.	Virginia Satir (1916-1988) Nationality: American Known for: The Mother of Family Therapy Satir conducted a wide variety of work within the family model. She felt that the family was simply a microcosm of the world and if families could get along peacefully, so could the world. She also published several books on the matter, including Conjoint Family Therapy in 1964.
Paul Watzlawick (1921-2007) Nationality: Austrian-American Known for: Worked in communication theory and radical constructivism Watzlawick theorized that humans are responsible for their own suffering as they create it by trying to fix their emotional problems. He also researched how families communicate and he explores five axioms in his theory, which he called the Interactional View.	Alice Miller (1923-2010) Nationality: Swiss Known for: Work extensively on the effects of parental child abuse Miller published several works about her discoveries concerning the effects of child abuse on children. Her book The Drama of the Gifted Child became a bestseller in various countries when it was first published in 1981. One of the theories she made was that child abuse led to violence later in life.	Albert Bandura (1925- ) Nationality: Canadian Known for: Formulated the social learning theory Bandura spent about six decades in the field of psychology studying different areas, including personality psychology, social psychology and behavioral psychology. He has been ranked as one of the top five cited psychologists in history, behind Sigmund Freud and B.F. Skinner.
Lawrence Kohlberg (1927-1987) Nationality: American Known for: Theory of stages of moral development Kohlberg is credited with creating the field of “moral development” in psychology while he worked on extending the findings of Jean Piaget. His “stages of moral development” explored how children react to various moral dilemmas, taking into account their age. He stated six stages of moral reasoning with his theory.	Philip Zimbardo (1933- ) Nationality: American Known for: Stanford prison study Zimbardo is known for a variety of reasons, including his published books regarding psychology. The Lucifer Effect may be his best known and it explores the theory of how good people change to evil. His main idea in the book is that good people often do bad things based on a given situation.	Stanley Milgram (1933-1984) Nationality: American Known for: Studied the effects of authority on obedience One of Milgram’s greatest studies was inspired by the Holocaust and the trial of one of its main participants- Adolf Eichmann. He wanted to study how far humans would go to carry out orders if an authority figure told them to do so. His peer shock experiment was very controversial, but it is a milestone in the field of psychology.
Paul Ekman (1934- ) Nationality: American Known for: Studied emotions and related facial expressions Given the title of the “best human lie detector in the world,” Paul Ekman established an “atlas of emotions” which links a particular emotion to the facial expressions that people make when they experience that emotion. His breakthrough discovery is the “micro-expression.”	Daniel Kahneman (1934- ) Nationality: Israeili-American Known for: Extensive work on the psychology of judgment In addition to judgment psychology, Kahneman also explored the idea of hedonic psychology, which is the study of what makes experiences in life either pleasant or unpleasant. One idea he helped develop was the “focusing illusion,” which places more emphasis on an aspect of one’s happiness than other factors.	Martin Seligman (1942- ) Nationality: American Known for: Developed the theory of learned helplessness Seligman’s idea of learned helplessness explores the theory that humans or animals are conditioned to behave as if they are helpless when they find themselves in certain situations. He related this idea to clinical depression and mental illness in which a person has a perceived lack of control over their situation.
Ken Wilber (1949- ) Nationality: American Known for: Formulated the Integral Theory Wilber has made many contributions to the field of psychology. At the center of his work is the idea of AQAL, or All Quadrants All Levels.” This idea involves various categories displayed in a quadrant system as they explore various viewpoints.	Steven Pinker (1954- ) Nationality: Canadian Known for: Known for supporting the idea of evolutionary psychology One of Pinker’s specialty areas of study is psycholinguistics. He has explored theories as to how children begin understanding language from an early age. He has published several books on the topic, including The Language Instinct, How the Mind Works, and The Blank Slate.