Timeline of Psychology

387BC: Plato suggested that the brain is the mechanism of mental processes.

335BC: Aristotle suggested that the heart is the mechanism of mental processes.

1774AD: Franz Mesmer detailed his cure for some mental illness, originally called mesmerism and now known as hypnosis.

1793: Philippe Pinel released the first mental patients from confinement in the first massive movement for more humane treatment of the mentally ill.

1808: Franz Gall wrote about phrenology (the idea that a person's skull shape and placement of bumps on the head can reveal personality traits.

1834: Ernst Heinrich Weber published his perception theory of 'Just Noticeable Difference,' now known as Weber's Law.

1848: Phineas Gage suffered brain damage when an iron pole pierces his brain. His personality was changed but his intellect remained intact suggesting that an area of the brain plays a role in personality.

1859: Charles Darwin published the On the Origin of Species, detailing his view of evolution and expanding on the theory of 'Survival of the fittest.'

1861: French physician Paul Broca discovered an area in the left frontal lobe that plays a key role in language development.

1869: Sir Francis Galton, Influenced by Charles Darwin's 'Origin of the Species,' publishes 'Hereditary Genius,' and argues that intellectual abilities are biological in nature.

1874: Carl Wernicke published his work on the frontal lobe, detailing that damage to a specific area damages the ability to understand or produce language

1878: G. Stanley Hall received the first American Ph.D. in psychology. He later founded the American Psychological Association.

1879: Wilhelm Wundt founded the first formal laboratory of Psychology at the University of Leipzig, marking the formal beginning of the study of human emotions, behaviors, and cognitions.

1883: The first laboratory of psychology in America is established at Johns Hopkins University by G. Stanley Hall.

1885: Herman Ebbinghaus introduced the nonsense syllable as a means to study memory processes.

1896: Lightner Witmer opens the first psychological clinic in the United States, focusing on the assessment and treatment of individuals with learning difficulties.

1886: Sigmund Freud began performing therapy in Vienna, marking the beginning of personality theory.

1890: The term "Mental Tests" was coined by James Cattell, beginning the specialization in psychology now known as psychological assessment.

1890: Sir Francis Galton developed the technique known as the correlation to better understand the interrelationships in his intelligence studies.

1890: William James published 'Principles of Psychology,' that later became the foundation for functionalism.

1890: New York State passed the State Care Act, ordering indigent mentally ill patients out of poor-houses and into state hospitals for treatment and developing the first institution in the U.S. for psychiatric research.

1892: Foundation of the American Psychological Association (APA) headed by G. Stanley Hall, with an initial membership of 42.

1895: Alfred Binet founded the first laboratory of psychodiagnosis.

1896: Writings by John Dewey began the school of thought known as functionalism.

1896: Lightner Witmer opens the first psychological clinic in the United States, focusing on the assessment and treatment of individuals with learning difficulties.

1898: Edward Thorndike developed the 'Law of Effect,' arguing that "a stimulus-response chain is strengthened if the outcome of that chain is positive."

1900: Sigmund Freud published 'Interpretation of Dreams' marking the beginning of Psychoanalytic Thought.

1901: The British Psychological Society was founded.

1905: Alfred Binet's Intelligence Test, the first practical intelligence test, was published in France. It focused on identifying children with learning disabilities.

1906: The Journal of Abnormal Psychology was founded by Morton Prince.

1908: Ivan Pavlov published the first studies on Classical Conditioning laying the foundation for behaviorism.

1911: Alfred Adler left Freud's Psychoanalytic Group to form his own school of thought, accusing Freud of overemphasizing sexuality and basing his theory on his own childhood.

1911: Edward Thorndike published first article on animal intelligence leading to the theory of Operant Conditioning.

1912: William Stern developed the original formula for the Intelligence Quotient (IQ) after studying the scores on Binet's intelligence test. The formula is

1912: Max Wertheimer published research on the perception of movement, marking the beginnings of Gestalt Psychology.

1913: John E. Watson published 'Psychology as a Behaviorist Views It' marking the beginnings of Behavioral Psychology.

1913: Carl G. Jung departed from Freudian views and developed his own theories citing Freud's inability to acknowledge religion and spirituality. His new school of thought became known as Analytical Psychology.

1915: Carl Jung publishes "The Theory of Psychoanalysis," introducing his ideas on the collective unconscious and archetypes.

1916: Stanford-Binet intelligence test was published in the United States.

1917: Robert Yerkes (President of APA at the time) developed the Army Alpha and Beta Tests to measure intelligence in a group format. The tests were adopted for use with all new recruits in the U.S. military a year later.

1919: Wolfgang Köhler publishes "The Mentality of Apes," pioneering the field of Gestalt psychology.

1920: John B. Watson and Rosalie Rayner published the Little Albert experiments, demonstrating that fear could be classically conditioned.

1921: Hermann Rorschach develops the Rorschach inkblot test, a projective psychological test used to assess personality traits and psychopathology.

1921: Psychological Corporation launched the first psychological test development company, not only commercializing psychological testing, but allowing testing to take place at offices and clinics rather than only at universities and research facilities.

1925: Mary Whiton Calkins becomes the first female president of the American Psychological Association (APA).

1925: Wolfgang Kohler published 'The Mentality of Apes' which became a major component of Gestalt Psychology.

1927: Anna Freud, daughter of Sigmund Freud, published her first book expanding her father's ideas in the treatment of children.

1929: Wolfgang Kohler criticizes behaviorism in his publication on Gestalt Psychology.

1927: The publication of "The Mental Hygiene Movement" by Clifford Beers promotes the idea of mental health promotion and prevention.

1932: The APA publishes the first edition of the "Ethical Standards of Psychologists," establishing ethical guidelines for the profession.

1932: Jean Piaget published 'The Moral Judgment of Children' beginning his popularity as the leading theorist in cognitive development.

1932: Walter B. Cannon coined the term homeostasis and began research on the fight or flight phenomenon.

1935: Thematic Apperception Test (TAT) was published by Henry Murray.

1936: Karen Horney publishes "The Neurotic Personality of Our Time," contributing to the field of psychodynamic theory and feminist psychology.

1936: Egas Moniz published his work on frontal lobotomies as a treatment for mental illness.

1938: Electroshock therapy was first used on a human patient.

1938: B.F. Skinner publishes "The Behavior of Organisms," outlining the principles of operant conditioning.

1939: Wechsler-Bellevue Intelligence Test was published which eventually became the most widely used intellectual assessment.

1939: The Canadian Psychological Association was founded.

1942: Carl Rogers published 'Counseling and Psychotherapy' suggesting that respect and a non-judgmental approach to therapy is the foundation for effective treatment of mental health issues.

1942: Jean Piaget published 'Psychology of Intelligence' discussing his theories of cognitive development.

1942: Minnesota Multiphasic Personality Inventory (MMPI) was developed and fast became the most widely researched and widely accepted psychological assessment device.

1943: Abraham Maslow presents his hierarchy of needs theory, a seminal contribution to humanistic psychology.

1945: The state of Connecticut passed licensure legislation for psychologists, becoming the first state to recognize psychology as a protected practice oriented profession.

1945: The Journal of Clinical Psychology was founded.

1945: Karen Horney published her feministic views of psychoanalytic theory, marking the beginning of feminism.

1947: George A. Miller publishes "The Magical Number Seven, Plus or Minus Two," discussing the capacity limits of human memory.

1949: Boulder Conference outlines scientist-practitioner model of clinical psychology, looking at the M.D. versus Ph.D. used by medical providers and researchers, respectively.

1950: Erik Erikson published 'Childhood and Society,' where he expands Freud's Theory to include social aspects of personality development across the lifespan.

1952: A study on psychotherapy efficacy was published by Hans Eysenck suggesting that therapy is no more effective that no treatment at all. This prompted an onslaught of outcome studies which have since shown psychotherapy to be an effective treatment for mental illness.

1952: The Diagnostic and Statistical Manual of Mental Disorders (DSM) was published by The American Psychiatric Association marking the beginning of modern mental illness classification.

1952: Chlorpromazine (Thorazine) first used in the treatment of schizophrenia.

1953: B.F. Skinner outlined behavioral therapy, lending support for behavioral psychology via research in the literature.

1953: Code of Ethics for Psychologists was developed by the American Psychological Association.

1954: Abraham Maslow helped to found Humanistic Psychology and later developed his famous Hierarchy of Needs.

1957: Carl Rogers introduces client-centered therapy, emphasizing empathy, congruence, and unconditional positive regard in therapeutic relationships.

1957: Leon Festinger proposed his theory of 'Cognitive Dissonance' which explores the discomfort caused by conflicting beliefs and attitudes.

1959: Harry Harlow's research on infant attachment using rhesus monkeys challenges prevailing beliefs and highlights the importance of contact comfort.

1961: John Berry introduced the importance of cross-cultural research bringing diversity into the forefront of psychological research and application.

1961: Carl Rogers published 'On Becoming a Person,' marking a powerful change in how treatment for mental health issues is conducted.

1961: Albert Bandura publishes his famous Bobo doll experiment, demonstrating the role of observational learning and social modeling.

1963: Lawrence Kohlberg introduced his ideas for the sequencing of morality development.

1967: Aaron Beck published a psychological model of depression suggesting that thoughts play a significant role in the development and maintenance of depression.

1967: Stanley Milgram conducts his obedience experiments, revealing the power of situational influences on human behavior.

1968: DSM II was published by the American Psychiatric Association.

1968: First Doctor of Psychology (Psy.D.) professional degree program in Clinical Psychology was established in the Department of Psychology at The University of Illinois - Urbana/Champaign.

1969: Joseph Wolpe published 'The Practice of Behavior Therapy.'

1971: Philip Zimbardo conducts the Stanford prison experiment, illustrating the impact of social roles and situational factors on behavior.

1971: First Doctorate in Psychology (Psy.D.) awarded (from The University of Illinois - Urbana/Champaign).

1973: APA endorsed the Psy.D. degree for professional practice in psychology.

1977: Albert Ellis develops Rational Emotive Behavior Therapy (REBT), a cognitive approach to psychotherapy.

1980: DSM III published by the American Psychiatric Association.

1983: Howard Gardner (professor at Harvard University) introduced his theory of multiple intelligence, arguing that intelligence is something to be used to improve lives not to measure and quantify human beings.

1988: American Psychological Society established.

1988: Martin Seligman introduces the concept of positive psychology, focusing on well-being, happiness, and human strengths.

1990: The Human Genome Project begins, leading to significant advancements in the study of genetic influences on behavior and mental health.

1990: The emergence of managed care prompts the APA to become more political, leading to the idea of Prescribing Psychologists and equity in mental health coverage.

1994: DSM IV published by the American Psychiatric Association.

1995: Daniel Goleman popularizes the concept of emotional intelligence in his book "Emotional Intelligence: Why It Can Matter More Than IQ."

1995: First Psychologists prescribe medication through the U.S. military's psychopharmacology program.

1997: Deep Blue, the supercomputer at the time, beats the World's best chess player, Kasparov, marking a milestone in the development of artificial intelligence.

1998: The first International Congress of Positive Psychology takes place, promoting research on positive aspects of human functioning.

1998: Psychology advances to the technological age with the emergence of e-therapy.

1999: Psychologists in Guam gain prescription privileges for psychotropic medication.

2000: Martin Seligman becomes president of the American Psychological Association and elevated Positive Psychology to the forefront.

2002: New Mexico becomes the first state to pass legislation allowing licensed psychologists to prescribe psychotropic medication.

2002: The push for mental health parity gets the attention of the White House as President George W. Bush promotes legislation that would guarantee comprehensive mental health coverage.

2003: Elizabeth Loftus's research on false memories demonstrates the malleability of human memory and its susceptibility to manipulation.

2005: Ellen Langer publishes "Counterclockwise," highlighting the potential of mindfulness and mind-body connections.

2009: The first World Happiness Report is released, assessing global levels of happiness and well-being.

2010: The field of neuropsychology witnesses significant advancements with the development of brain imaging techniques, such as functional magnetic resonance imaging (fMRI).

2012: The replication crisis in psychology gains attention, leading to increased focus on research transparency and rigor.

2013: The DSM 5 is published by the American Psychiatric Association.

2013: The field of positive psychology expands with the emergence of positive education, applying positive psychology principles in schools.

2014: The American Psychological Association releases guidelines for psychological practice with transgender and gender nonconforming people.

2016: The "Ferguson Effect" is introduced, referring to the increased scrutiny of police behavior due to widespread use of smartphones and social media.

2017: The #MeToo movement gains momentum, shedding light on the pervasiveness of sexual harassment and assault.

2018: The American Psychological Association recognizes video game addiction as a mental disorder in the eleventh edition of the International Classification of Diseases (ICD-11).

2019: The World Health Organization includes burnout in the eleventh revision of the International Classification of Diseases (ICD-11).

2020: The COVID-19 pandemic leads to increased focus on mental health and well-being globally.

2021: Naomi Osaka's withdrawal from the French Open sparks discussions on athlete mental health and the pressures of professional sports.

2022: The use of virtual reality (VR) and augmented reality (AR) gains prominence in psychological research and therapy.

2023: The field of psychology continues to evolve and address new challenges, exploring topics such as artificial intelligence (AI) and its impact on human behavior.