Timeline
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600 BCE — 469 BCE
Cosmologists (Pre-Socratics)
First in recorded history to offer answers to questions about the natural world that will form the foundation of Western philosophy (epistemology and metaphysics) and science. Later Western philosophical positions (monism, pluralism, dualism, materialism, and rationalism) begin here.
510 BCE
Alcmaeon
First recorded observation that the brain is involved with sensory processes and that perception is mediated by pneuma (breath) contained within an animal or human body.
428 BCE — 347 BCE
Plato
Later philosophical positions of idealism, rationalism, and dualism can be seen in his thought (theory of forms). Ascribed mental properties to psyche/soul, and believed its physical location in the body was the brain.
384 BCE — 322 BCE
Aristotle
His investigations of the physical world form the basis of empiricism. Establishes the Lyceum in 335 BCE, a place where he can engage with his students in cooperative research in natural history. Aristotle seated the psyche/soul in the heart. He can be considered the founder of psychology as a discipline: he is the first to consider the problem of the psyche/soul as an object of study separate from other human concerns.
350 BCE
De Anima "On the Soul"
Aristotle. Treatise that defines the nature and activities (biological and psychological) of the psyche/soul.
323 BCE — 31 BCE
Roman philosophy
Concerns with happiness, maximizing personal gain, escape from the ills of the world (Skepticism, Epicureanism), but also moral behavior and self-restraint, moderation (Stoicism). Emphasis on the conduct of man in the here and now (rather than viewing conduct as linked to consequences in an afterlife).
31 BCE
Roman Empire begins
Caesar Augustus becomes first emperor of Rome.
100 — 165
Almagest
Claudius Ptolemy. Geocentric model of the apparent motions of the stars and planetary paths. Profoundly influential scientific text, it was accepted for more than 1,200 years through the early Renaissance.
129 — 199
Galen
Develops the humor theory of temperament (first typology of personality). The theory of the four humors did not originate with Galen, however; it is an iteration of Hippocrates's adapation of Empedocles's elemental theory of the cosmos.
129 — 199
pneuma theory
Galen incorporated the ancient concept of pneuma into his physiological theories: pneuma (breath, air) mediated between the soul/psyche and bodily action. Pneuma theory was revised as the animal spirits doctrine, a physiological theory of functions such as volition, muscle contraction, cognition, and sensation. The animal spirits doctrine was entrenched in classical medical thought until the late 1700s when Luigi Galvani's experiments in 1791 displaced it.
354 — 430
St. Augustine
Writes the Confessions of St. Augustine.
380
Christianity is official religion of Rome
Roman Empire officially adopts Christianity as its state religion.
476
Roman Empire (Western) ends
Roman Emperor Romulus Augustulus is replaced by Germanic King Odoacer. Invasions of the Roman Empire have hindered European education.
700 — 850
Carolingian Europe is a stable Europe
The rule of the Frankish king Charlemagne unites Western Europe under Christendom (literally a "realm of Christians") and a period of intellectual activity ensues. In monasteries and cathedrals, schools operate and commentaries and summaries of ancient texts appear.
800 — 1500
Islamic Golden Age
Islamic civilization flourishes and cities such as Baghdad, Istanbul, and Cordoba become centers for culture and intellectual activity (e.g., "The House of Baghdad", 832 CE). Learned individuals in these cities engage in a massive translation of scientific works from ancient Greece, Rome, and Egypt (essentiallly preserving this ancient knowledge, as many of the ancient texts were destroyed during the fall of the Roman Empire). Individuals such as Rhazes, Avicenna (Canon of Medicine), Alhazen (Book of Optics), Al-Ghazali, and Averroës made original contributions to knowledge in several areas, among them ophthalmology, astronomy, mathematics, physiology, and surgery. Averroës writes The Incoherence of the Incoherence, and On the Harmony of Religions and Philosophy; his position that philosophy can inform religion (Islamic scripture) had a lasting influence among later Western philosophers.
800 — 1000
Western Europe destabilizes
Charlemagne's empire distintegrates: Magyars, Muslims, and Vikings attack Western Europe. New political entities form (kingdoms in England, automous domains in West Francia [France], a Holy Roman Empire in East Francia [Gemany], and strong cities in the Italian peninsula) that are the basis of the European nation-states with which we are familiar today.
1000 — 1300
Conditions ripe in Europe for intellectual activity
Beginning around 1100 CE, Western Europe enjoys a period of improved conditions: fewer invasions, strong rulers, and even better weather are said to account for economic stability and intellectual growth.
1095
First Crusades
Pope Urban II summons Christian warriors to reconquer the Holy Land (drive Muslims from Jerusalem).
1100
Enormous intellectual activity in Europe
Intellectual activity begins to peak. It takes many forms: original scientific works produced by Islamic authors, the collection and dissemination of original texts of the ancient Greeks, commentaries on the ancient Greek texts written by Islamic authors (translated from Greek to Arabic), and the translation of these works from Arabic into Latin.
1100 — 1400
European universities emerge
Universities emerge as guilds (not buildings) of male students who train in the liberal arts and a few specialized disciplines: medicine, law, philosophy, theology.
1158
Charter granted to University of Bologna (Italy)
First university; oldest in the world. Specialities: canon and civil law.
1200
Charter granted to University of Paris
Known as the Sorbonne; second-oldest unversity. Specialities: philosophy and theology.
1210
Aristotle banned
Teaching of Aristotle's works forbidden at the University of Paris; seen as a threat to Christian doctrine.
1215
Magna Carta signed
English barons force King John of England to sign a document that guarantees, among other things, tax collection only by legal means and no imprisonment without trial. It is a foundation of modern democracy and a source of later legal systems.
1225 — 1274
Thomas Aquinas and Scholasticism
Italian philosopher and theologian whose works influenced Roman Catholic theology and Western philosophy. His professional life epitomized that of philosophers in a medieval university: their goal was to reconcile questions concerning faith (scripture) with reason so that Christian church teachings had a logical foundation. Scholasticism is both a learning method and philosophical system that peaked with Aquinas's work. It is a method of reasoning applied to the problem of reconciling the philosophy of ancient Greece with Christian theology (e.g., the nature of human beings, the existence and attributes of God).
1231
Charter granted to University of Cambridge
English university
1248
Charter granted to University of Oxford
English university
1300 — 1625
Renaissance
Cultural events occurring on a large, widespread scale in Europe, beginning in Italy and spreading to the rest of the continent. Among its defining intellectual features: rediscovery of Greek classics, new interest in mathematics, expanding geographic knowledge, wider epistemology.
1300 — 1625
Renaissance Humanism
Philosophical movement that reflects new interest in human affairs, manifested in art, music, literature, science. Generally speaking, a more human-centered, rather than religion-centered, perspective on life. Expressed in works of Francesco Petrarch, Niccolò Machiavelli, and Leonardo da Vinci.
1340
Black Plague
Italian ships bring rats carrying fleas infected with the Black Plague, which will kill 25 million people in Europe (one-third of the European population).
1400 — 1450
End of the medieval period
Defined by some historians as the fall of the Byzantine Empire; defined by others as the perfection of movable type by Johannes Gutenberg.
1403
Bethlem Hospital cares for mentally ill
London hospital that transitions to caring for people with mental illnesses. Informally known as "Bedlam".
1450 — 1524
First use (?) of term "psychology" to denote the science of mental life
Historical scholarship suggests that the first scholar to use the term "psychology" may have been Marko Marulić, a Croatian humanist. The term appears in the title Psichiologia de ratione animae humanae, in a list of his works (the actual work has not been found).
1453
Byzantine Empire (Eastern Roman) ends
Constantinople is conquered by Ottoman Muslims.
1487
The Malleus Maleficarium
Written by Heinrich Kramer and James Sprenger, "The Hammer of Witches" is a famous medieval treatise that instructs magistrates on how to identify, interrogate, and convict witches.
1492
Old World meets New World
Christopher Columbus makes first voyage to the Americas.
1517
Protestant Reformation begins
Martin Luther distributes his Disputation on the Power of Indulgences (also known as the Ninety-five Theses), which he wrote as a criticism of the Catholic Church's abuse of the practice of distributing indulgences (clergy receiving payment for granting indulgences).
1543
Start of Scientific (Copernican) Revolution
Profound transformation of thought, circa 1550 through 1700, about the physical world as ancient beliefs were replaced by modern science. Replaces the thinking of Aristotle, Ptolemy, and Galen of the Middle Ages. First occurs in mathematics, physics and astronomy, anatomy, and chemistry.
1543
On the Revolutions of the Celestial Spheres
Nicolas Copernicus. Often viewed as the start to the Scientific Revolution, it is a model of planetary motion based on the assumption that the Earth and other planets move around the Sun.
1543
On the Structure of the Human Body
Andreas Vesalius. A major advance in the history of anatomy, this collection of books was based on his dissections of corpses and features illustrations whose quality was far better than previous illustrations.
1583
University of Edinburgh
University established in Scotland that will earn Edinburgh a reputation as a major intellectual center during the Age of Enlightenment. One of the earliest universities founded without a Papal bull (charter issued from a Pope of the Roman Catholic Church).
1607
European settlement of the Americas
English establish a colony at Jamestown, Virginia.
1608
First telescope invented
Dutch scientist Hans Lippershey first to hold up two lenses placed some distance apart in order to bring an object's image closer. (Sadly, his patent request was denied.)
1609
Galileo Galilei builds his first telescope
Observations establish the validity of the Copernican model of the universe.
1620
Mayflower lands
Merchant ship named the Mayflower sets sail from Plymouth, England and lands in November on the tip of Cape Cod.
1620
Novum Organum (New Organon)
Francis Bacon. Recommends inductive reasoning and experimentation (consistent with empiricism as the means to obtain scientific knowledge, i.e. certainty) as the bases of the scientific method. Title is a reference to Aristotle's work, Organon, his treatise on logic.
1627
Brain and movement
William Harvey demonstrates in frogs that the brain plays a role in movement.
1628
On the Motion of the Heart and Blood
William Harvey describes the circulation of the blood.
1633
Galileo recants
The Roman Catholic Inquisition forces Galileo to rescind his Copernican view that the Earth moves around the Sun.
1637
Discourse on the Method of Rightly Conducting One's Reason and of Seeking Truth in the Sciences
René Descartes. One of the most important works in the history of modern philosophy. Descartes describes his use of the "method of doubt" (deductive reasoning) to achieve certain (scientific) knowledge. Through this process he arrives at foundational beliefs, one of which is the existence of material bodies that exist independently of an immaterial mind (description of the modern mind-body problem). The book is consistent with philosophies of dualism and rationalism.
1651
Leviathan
Thomas Hobbes's views on metaphysics (materialism) and human nature.
1658
First description of red blood cells
Jan Swimmerdam observes red blood cells under a microscope.
1662
Royal Society of London
Royal Society of London for Improving Natural Knowledge is chartered as a learned society of physicians and natural philosophers. It is the oldest existing such society today. The Royal Society and others like it are a very important part of the growth of science: such societies emerged in the 1600s to provide a forum for individuals to disseminate information about the natural sciences.
1663
René Descartes banned
René Descartes' works are placed on the Roman Catholic Church's Index of Prohibited Books.
1664
Electrical stimulation of muscles
Jan Swimmerdam uses electrical nerve stimulation to cause a frog's muscle to contract.
1664
Anatomy of the Brain
Thomas Willis. Most comprehensive and accurate description of the brain and nervous system to date.
1664
Treatise on Man
René Descartes' mechanistic model of humans.
1677
Ethics
Baruch Spinoza. Philosophical work that, in the style of solving a geometic problem, addresses questions of God, the structure of reality, and moral philosophy. His position on the nature of mind is termed "double aspectism".
1682
Witch executions end in England
England conducts its last witch execution.
1687
The Mathematical Principles of Natural Philosophy (The Principia)
Isaac Newton. Perhaps the greatest of all scientific works, it is the culmination of theory regarding the universe and physics from Aristotle through Copernicus. It states Newton's laws of motion and law of universal gravitation. Is significant, too, for its underlying message: the language of mathematics helps us decipher the material world, not scripture. Authority lies with the scientific method, not the spiritual or divine.
1690
An Essay Concerning Human Understanding
John Locke. Humans acquire knowledge through experience (repeated exposure) that has its origins in one source: sense data. Is consistent with the philosophy of empiricism.
1695
The Anatomy of the Brain Containing its Mechanisms and Physiology
Humphrey Ridley. First English-language treatise of neuroanatomy.
1700 — 1800
The Scottish School
School of philosophical thought that influenced psychology (through works of Thomas Reid, Dugald Steward, and Thomas Brown). Many individuals who became faculty members at the newly created American universities followed tenets of this school.
1709
An Essay Towards a New Theory of Vision
George Berkeley's empirical theory of vision that contrasted with standard accounts of the day (based on geometric calculations). Berkeley's account is that we cannot actually "see" the distance of objects; instead, the association of ideas of sight and touch explains how we perceive distance.
1710
A Treatise Concerning the Principles of Human Knowledge
George Berkeley's empiricist argument that knowledge derives from the experience of one's own mind (ideas), rather than physical objects. The text supports two metaphysical positions: idealism (all that exists is a mind or depends on mind for its existence) and immaterialism (matter does not exist).
1714
The Monadology
Gottfried Wilhelm Leibniz. A metaphysics of substance (psychophysical parallelism).
1739
A Treatise of Human Nature
David Hume. Addresses the problem of human knowledge, the passions, and morals.
1748
An Enquiry Concerning Human Understanding
David Hume. Ideas and impressions as a source of experience, the laws of association, and an influential analysis of the concept of causation as a product of association.
1749
Observations on Man, his Frame, his Duty, and his Expectations
David Hartley's work is the first attempt to adopt association as the fundamental operation of all ideas and behaviors. Explains how mental associations are formed and identifies neurophysiological activity as their origin.
1751
First volume of Encyclopedia, or Rational dictionary of science, art, and custom
First volume of what is more generally known as the Encyclopedia, published by Jean le Rond d'Alembert and Denis Diderot.
1754
Treatise on Sensations
Étienne Bonnot de Condillac. Knowledge reaches humans only through the senses.
1757
Elements of the Physiology of the Human Body
Albrecht von Haller. Surveys physiological knowledge of the time and describes Haller's studies on muscles and human blood circulation.
1758
Essays on the Mind
Claude Adrien Helvetius. Mind develops as a result of sensations it perceives, not as a product of innate tendencies.
1764
Observations on nervous, hypochondriacal, or hysteric diseases
Robert Whytt. One of the first important textbooks on neurology.
1766
Nerves control muscle contraction
Albrecht von Haller shows that nerves stimulate muscle contraction and all nerves lead to spinal cord and brain.
1776
Declaration of Independence signed
Expresses the ideals on which the United States was founded and its reasons for separation from Great Britain.
1781
Critique of Pure Reason
Immanuel Kant. One of the most important works in philosophy for its analysis of the nature of metaphysics.
1789
French Revolution begins
A citizen mob storms the Bastille prison in Paris on July 14.
1792
A Vindication of the Rights of Woman
Mary Wollstonecraft. One of the earliest works of feminist philosophy.
1802
Color vision
Thomas Young suggests that the ability to perceive color depends on the presence of three types of nerves in the retina.
1805
On the activities of the brain
Franz Joseph Gall incorrectly argues that the brain can be studied by examining the contours of a person's skull—phrenology. (His underlying assumption that different parts of the brain generally do have different functions was accurate.)
1806
A Treatise on Insanity
Philippe Pinel. Provides an improved classification for mental illness and an argument for moral (talk) therapy.
1809
Zoological Philosophy
Jean-Baptiste Lamarck. Describes a theory of inheritance of acquired characteristics (first complete theory of evolution) that was eventually discredited.
1811
Idea of a New Anatomy of the Brain
Charles Bell. Describes the difference between sensory and motor nerves. Bell's Law: the anterior spinal roots are motor and the posterior roots are sensory (also Bell-Magendie Law).
1812
Medical Inquiries and Observations Upon the Diseases of the Mind
Benjamin Rush. First textbook of psychopathology in America.
1816
Textbook of Psychology
Johann Herbart.
1821
Copernicus ban lifted
The Roman Catholic Church lifts its ban on teaching Copernican physics.
1824 — 1825
Psychology as a Science
Johann Herbart. Mathematical expression of laws by which mental representations (ideas) interact. Describes ideas in terms of equilibrium and mechanics ("force", "inhibition").
1826
Sensation, perception, physiology
Ernst Heinrich Weber begins experiments with the two-point threshold of sensation.
1829
An Analysis of the Phenomena of the Human Mind
James Mill's mechanistic/associationist account of mental processes.
1830
The Course in Positive Philosophy
Six-volume work by Auguste Comte establishes positivism as philosophical school.
1831
Beginnings of social statistics
Lambert Adophe Jacques Quetelet studies how variables such as gender, age, education, climate and season affect the crime rate in France.
1833
Handbook of Physiology
Johannes Peter Müller proposes theory that each nerve has its own specific energy (doctrine of specific nerve energies).
1834
Weber's Law
Ernst Weber. The change in stimulus intensity that can just be discriminated is a constant ratio of the initial intensity of the physical stimulus. In other words, the more intense the stimulus, the greater the change that must be made in it to be noticed.
1835
HMS Beagle
Charles Darwin travels to Galapagos Islands as scientific officer on the ship. Observes that closely related finches seem to have descended from a common ancestor on the South American mainland.
1841
Dorothea Dix brings attention to plight of people with mental illness
Begins her investigations into the treatment of people with mental illness in Massachusetts.
1850
Speed of a nerve impulse
Hermann von Helmholtz is first scientist to make precise measurements of nervous action.
1850
Interest in comparative psychology emerges
See works of George Romanes, Conwy Lloyd Morgan.
1850
Fechner Day
October 22. Gustav Fechner realizes that he can address the mind-body problem by comparing physical measures and psychological appearances. He investigated psychophysics for the rest of his life, laying the foundation for experimental psychology.
1859
On the Origin of Species
Charles Darwin
1860
Weber-Fechner Law
Gustav Fechner's adaptation of Weber's Law. Establishes a scale of sensation magnitude having a zero-point value and a basic unit of measurement (just noticeable difference [JND]). Significance: sensation magnitude can be measured indirectly by relating values of change on the physical scale to corresponding values on a psychological scale (the JND difference in sensation).
1860
The Elements of Psychophysics
Gustav Fechner. One of the most important books in the history of psychology. Describes conceptual issues in measuring physical and psychological worlds, Fechner's own experimental work, and psychophysical methods.
1861
Broca's Area established
Pierre Paul Broca demonstrates that loss of speech is related to a lesion in the left frontal lobe.
1861 — 1865
American Civil War
Confederate States of America formed by South Carolina and ten other Southern states. First battle at Bull Run is a Confederate victory.
1862
Treatment of nervous system disorders at La Salpêtriėre, Paris
Jean-Martin Charcot begins his clinical studies of nervous system disorders, including hysteria.
1863
Reflexes of the Brain
I. M. Sechenov attempts to analyze higher-order functions in terms of the reflex action. Reflects the Russian objective psychology that later influences American behaviorism.
1863
National Academy of Sciences
Group of scientists based largely in Cambridge, Massachusetts solicited the Massachusetts senator to draft a bill of incorporation.
1864
Principles of Biology
Herbert Spencer. Coins term "survival of the fittest"".
1865
Laws of genetics
Gregor Mendel publishes his theories of genetics.
1869
Hereditary Genius
Francis Galton publishes his work in historiometry
1870
First direct stimulation of the brain
Gustave T. Fritsch and Julius Eduard Hitzig discover that the cerebral cortex has different compartments for different functions and introduce electrical stimulation as a means to study the brain.
1873 — 1874
Principles of Physiological Psychology
Wilhelm Wundt's lecture notes organized into chapters. One of the most important works in the history of psychology.
1876
Functions of the Brain
David Ferrier. Collections of experiments on brain localization, regarded as among the most important advances in physiology at the time of its publication.
1877
Lectures on the Diseases of the Nervous System
Jean-Martin Charcot
1879
Psychology becomes an experimental science
Wilhelm Wundt founds the first psychological laboratory at the University of Leipzig, Germany.
1879
Mind
First journal devoted to psychological research. Created by Alexander Bain.
1881
Philosophical Studies
Outlet for research from Wundt's laboratory. First academic journal for psychological research.
1885
Sigmund Freud studies with Jean-Martin Charcot at La Salpêtriėre
His observations of Charcot's hypnotic treatment of hysteria will greatly influence Freud's later ideas and the development of psychoanalysis.
1885
On Memory
Hermann Ebbinghaus's foundational work on memory that includes his "curve of forgetting" (how much is retained in human memory over time).
1888
Concept of correlation ("co-relation")
Francis Galton describes the interdependence of two sets of variables.
1890
On Gestalt Qualities
Chistian von Ehrenfels. First proposal of Gestalt concept.
1890
Principles of Psychology
William James writes textbook that surveys major topics of study in psychology at the time. Book will be used in American universities for decades.
1892
American Psychological Association
G. Stanley Hall instrumental in creating this professional society.
1892 — 1924
Ellis Island and the nation's immigrants
12 million European immigrants arrive at this New York City inspection station during this period. This event can be viewed as a factor in the emergence of the mental testing movement.
1893
World's Columbian Exposition, Chicago, Illinois
Psychology is recognized as an official exhibit at this celebration of American culture. Visitors can view a collection of psychological instruments and pay a fee to access a testing room to have their mental and sense powers assessed.
1893 — 1901
Early experimental methods handbooks
E. B. Titchener and Edmund Sanford produce textbooks for university use.
1893 — 1895
Studies on Hysteria
Sigmund Freud and Josef Breuer. Technical procedures (Breuer's cathartic method) and clinical findings addressed in the book will influence Freud to adopt psychoanalysis as a treatment for hysteria.
1894
Pullman strike
Pullman railroad car plant in Chicago is the site of a violent workers' strike. Symbolic of labor unrest throughout the nation in the late 1800s. American functionalists see the potential for psychological science to help alleviate such real-world problems.
1894
First woman to earn PhD in psychology
Margaret Floy Washburn
1895
Mary Whiton Calkins
Unofficially defends her dissertation at Harvard University.
1896
The Reflex Arc Concept in Psychology
John Dewey. Establishes key tenet of American functionalism: an emphasis on the role of adaptation in an organism's behavior.
1898
The Postulates of a Structural Psychology
E. B. Titchener. Establishes structuralism as a psychological school of thought.
1904
The Experimentalists
E. B. Titchener begins a small, elite scientific society to promote psychology as an experimental science. Membership closed to female or non-experimental psychologists.
1905
Mary Whiton Calkins
First woman president of the American Psychological Association.
1905
First usable intelligence test created
Alfred Binet and Théodore Simon
1907
The Province of Functional Psychology
James Rowland Angell's description of the psychology practiced by several prominent psychologists at various American universities. Contrasts with Titchener's structuralism.
1907
The Psychological Clinic
Lightner Witmer establishes the only clinical psychology journal of the time and it becomes instrumental in shaping this subfield.
1908
A Mind that Found Itself
Clifford Beers's autobiographical account of his experiences as a patient in an asylum. The book inspired the mental hygiene movement in the United States.
1908
On the Witness Stand
Hugo Münsterburg. Psychology as applied to courts, legal system. Reflects a tenet of American functionalist thought: psychological methods should be applied to practical problems outside the laboratory.
1909
Freud's first and only visit to America
G. Stanley Hall organizes the Clark University Conference at which Freud is an invited speaker.
1909
NAACP established
National Association for the Advancement of Colored People established in the United States.
1911
Animal Intelligence
E. L. Thorndike
1912
The intelligence quotient
William Stern labels the mental age divided by the chronological age the 'intelligence quotient'. (Lewis Terman will later abbreviate to IQ.)
1912
Phi phenomenon
Max Wertheimer. Publication titled Experimental Studies of the Perception of Movement is a foundational document for the Gestalt system of thought.
1913
Psychology as the Behaviorist Views It
John B. Watson's description of tenets of behaviorism. Usually cited as the origin of behaviorism.
1914 — 1918
World War I begins
Archduke Franz Ferdinand of Austria is assassinated.
1917
United States declares war on Germany
American enters WW I.
1917
Psychology and WW I
Robert Yerkes introduces Army Alpha and Army Beta tests. Tests are used to screen potential military recruits for fitness to serve.
1919
Treaty of Versailles
Peace treaty that ended the state of war between Germany and the Allied powers.
1920
Nineteenth Amendment to the US Constitution
Voting rights legally guaranteed for American women.
1920
Fear is a conditioned response
Study by J. Watson and R. Rayner that demonstrated that an emotional reaction could be learned via classical conditioning. Consistent with behaviorism.
1920
First African American doctorate in psychology
Frances Cecil Sumner at Clark University
1921
Acetylcholine confirmed as first neurotransmitter
Otto Loewi
1921
Rorschach test created
Hermann Rorschach develops personality test based on interpretation of inkblots.
1921
American Birth Control League established
Margaret Sanger reponsible for establishing the organization which would eventually become the Planned Parenthood Federation of America.
1924 — 1933
Hawthorne experiments
Managers at the Hawthorne works of Western Electric Company (Illinois) collaborate with Elton Mayo and Fritz Roethlisberger at the Harvard Business School to conduct experiments on variables such as worker productivity and job satisfaction. Studies reflect the growing belief that scientific methods could be applied to real-world settings. The research uncovered the "Hawthorne effect": humans will alter their behavior in response to knowledge that they are under observation.
1925
Scopes monkey trial
State of Tennessee v. John Thomas Scopes. Nationally publicized trial which pits evolutionary theory against biblical scripture when a high school teacher agrees to be tried for violating state law that prohibited teaching evolution in public schools. Scopes was found guilty and fined and the verdict was later overturned.
1925
Menninger Clinic founded
Charles Frederick Menninger and sons open clinic emphasizing psychiatry and psychology in treatment of mental illness.
1927
The Logic of Modern Physics
Percy W. Bridgman argues that all physical concepts must be defined in precise terms and that concepts lacking physical references must be discarded.
1927
Conditioned Reflexes
Ivan Pavlov's physiological studies of digestion in dogs are the foundation of classical conditioning and an influence on the development of American behaviorism.
1929 — 1939
Great Depression
New York stock market crashes and begins Great Depression.
1929
Electroencephalogram invented
Psychiatrist Hans Berger invents instrument to graph electrical activity of the brain.
1933 — 1945
Adolf Hitler is elected Chancellor of Germany
Will remain Chancellor through the end of World War II.
1935
Alcoholics Anonymous founded
Bill Wilson and Dr. Robert Smith establish treatment model for addiction that features social support groups.
1936
First human frontal lobotomy
Egan Moniz
1936
Model of computability
Alan M. Turing publishes a paper which introduces the concept of a Turing Machine.
1937
The Neurotic Personality of Our Time
Karen Horney. Publication reflects psychoanalytic theory among psychoanalytic theorists following Freud.
1938
The Behavior of Organisms
B. F. Skinner (behaviorism)
1938
First use of electroshock therapy
Ugo Cerletti and Lucino Bini
1939 — 1945
World War II begins
Germany invades Poland.
1941
United States enters World War II
United States declares war on Axis powers following bombing of Pearl Harbor by Japanese.
1942
Counseling and Psychotherapy
Carl Rogers. Exemplifies tenets of humanistic psychology.
1943
A Theory of Human Motivation
Abraham Maslow. Journal publication that exemplifies tenets of humanistic psychology.
1946
Mental Health Act passed
President Harry S. Truman signs law that funds psychiatric education and research for first time in United States history.
1948
Male and Female: A Study of the Sexes in a Changing World
Margaret Mead's claim that many aspects of Western culture are a product of Western child-rearing practices.
1949
Leucotomy
Egas Moniz awarded Nobel Prize in Physiology or Medicine for the therapeutic procedure he developed for psychosis.
1949
Information theory
Claude Shannon publishes his mathematical theory of information.
1949
Recommendation that doctoral programs train clinical psychologists as research-practitioners
Boulder Conference on Graduate Education in Clinical Psychology
1950
Childhood and Society
Erik Erikson. Publication reflects psychoanalytic theory among psychoanalytic theorists following Freud.
1951
Client-Centered Therapy
Carl Rogers. Exemplifies tenets of humanistic psychology.
1952
First edition of the Diagnostic and Statistical Manual of Mental Disorders published
American Psychiatric Association
1953
DNA modeled
James Dewey Watson and Francis H. Crick develop the double-helix model for deoxyribonucleic acid (DNA). Explains how the molecule can transmit heredity in living organisms.
1954
The Nature of Prejudice
Gordon Allport. Book helped to promote the study of prejudice.
1954
Army-McCarthy hearings
Concern over Communist Party presence in America culminates in Army-McCarthy hearings before the US Senate.
1954
Brown v. Board of Education
United States Supreme Court declares that laws establishing separate public schools for black and white students are unconstitutional.
1956
Information theory applied to cognitive processes
George Miller reviews research findings and concludes that they can be explained by information theory.
1959
Chomsky's review of Skinner's Verbal Behavior
Linguist Noam Chomsky writes a powerful critique of B. F. Skinner's book (behavioral principles cannot explain language acquisition). Supports growing sentiment that a purely behavioral explanation of human functioning is not valid.
1960
Behavior Genetics
John L. Fuller and W. Robert Thompson. Text inspired interest in modern genetic theory as it applies to inherited behavior.
1960
Interest in cultural factors in psychological processes intensifies
Culture becomes a topic of research programs across a critical mass of scholars. For seminal studies, see, for instance, individual and collaborative works by D. C. McClelland, J. W. Berry, R. Benedict, M. H. Segall, and M. J. Herskovits.
1961
The Myth of Mental Illness
Thomas Szasz writes a powerful critique of his psychiatric profession.
1961
Journal of Humanistic Psychology
Journal is a forum for psychologists who advocate a perspective on psychology that is an alternative ("third force") to the dominant schools of thought (behaviorism and psychoanalysis).
1961
Humans venture into the last frontier
Russian cosmonaut Yuri Gagarin becomes first man in space.
1963
March on Washington
Martin Luther King, Jr. delivers his historic "I Have a Dream" speech in front of the Lincoln Memorial to call for an end to racism.
1963
Community Mental Health Centers Act passed
President John F. Kennedy signs act that funds construction of community-based centers for psychiatric treatment. Program ends in 1981.
1963
Cognitive therapy established
Aaron T. Beck's 1963 article "Thinking and depression: Idiosyncratic content and cognitive distortions" is central to theory and research on cognitive techniques for treating mental illness.
1963
The Feminine Mystique
Betty Friedan's book greatly influenced a mid-century interest in feminism.
1964
Civil Rights Act passed in United States
President Lyndon B. Johnson signs bill that outlaws discrimination based on race, color, religion, sex, or national origin.
1964
First National Medal of Science awarded to psychologist
Neal E. Miller for studies of motivation and learning.
1965 — 1973
United States involvement in the war in Vietnam
General American reaction is one of protest.
1965
Harlow's monkeys
Harry Harlow's experimental research demonstrates that monkeys reared in isolation exhibit great emotional impairment later in their development.
1966
National Organization for Women
Feminist organization established to ensure legal enforcement of national anti-discrimination laws already in place.
1967
Cognitive Psychology
Ulric Neisser's perspective on psychology that focuses on the operation of mental processes.
1967
Split brain research
Michael S. Gazzinga reports that studies of people whose brain halves have been severed show that the two halves can function independently
1968
Association of Black Psychologists
Established as a forum through which African American psychologists could address professional needs neglected by existing organizations.
1969
Neil Armstrong and Buzz Aldrin land on moon
Apollo 11 successfully places a manned vehicle on the moon.
1973
Homosexuality removed from Diagnostic and Statistical Manual of Mental Disorders
Professional conceptualization of people who are homosexual or bisexual is no longer one of illness.
1973
Nobel Prize for research in social behavior
Karl von Frisch, Konrad Lorenz, and Nikolass Tinbergen jointly awarded the Nobel Prize in Physiology or Medicine for their ethological studies.
1975
Sociobiology: The New Synthesis
E. O. Wilson's controversial book introduces "sociobiology" as the study of the biological basis of social behavior. Influential in development of evolutionary psychology.
1976
The Selfish Gene
Richard Dawkins's book shifts focus from evolutionary change at the level of either the species or organism to evolutionary change at the level of the gene. Popularizes evolutionary psychology.
1978
Society for Health Psychology
Division 38 of the American Psychological Association established.
1978
Nobel Prize for decision-making research
Herbert Simon awarded the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel for research in decision-making within economic organizations.
1979
Eyewitness Testimony
Elizabeth Loftus. Review of psychological research that argues against the use of eyewitness testimony.
1979
Larry P. v Wilson Riles
U. S. District Court decision that finds that IQ tests discriminate against African American students.
1979
The Ecological Approach to Perception
Book represents the culmination of the theory and research by J. J. Gibson who advocates that cognitive processes are not necessary for an organism to perceive—information from an observer's environment is the critical component in perception. Significant work in visual perception and ecological psychology.
1981
Assassination attempt on Ronald Reagan
John W. Hinckley shoots four individuals in an attempt to assassinate President Reagan. Event is a factor in the Insanity Defense Reform Act of 1984 which makes it difficult to obtain a verdict of not guilty by reason of insanity in the United States.
1981
Nobel Prize for advances in cerebral function research
Roger W. Sperry shares the Nobel Prize in Physiology or Medicine for discoveries concerning functional specialization in cerebral hemispheres.
1981
Nobel Prize for information processing research
David H. Hubel and Torsten N. Wiesel share the Nobel Prize (with R. W. Sperry) in Physiology or Medicine for discoveries concerning information processing in the visual system.
1981
The Mismeasure of Man
Stephen Jay Gould's critique of biological determinism.
1981
Computers come to the people
The IBM personal computer (and the industry-standard disk operating system [DOS]) is introduced.
1983
Frames of Mind: The Theory of Multiple Intelligences
Theory of multiple intelligences by Howard Gardner.
1984
DNA successfully cloned
University of California scientists Allan Wilson and Russell Higuchi successfully clone DNA from an extinct animal.
1985
Society for the Psychological Study of Lesbian, Gay, Bisexual and Transgender Issues
Division 44 of the American Psychological Association established.
1986
Society for the Psychological Study of Culture, Ethnicity and Race
Division 45 of the American Psychological Association established.
1986
Society for Sport, Exercise and Performance Psychology
Division 47 of the American Psychological Association established.
1986
Prozac enters medical use for mental illness
Fluoxetine prescribed for depression.
1988
American Psychological Society established
Professional association for the advancement of psychology as a science. Known now as Association for Psychological Science.
1991
Learned Optimisn
Martin Seligman. Establishes positive psychology movement.
1997
International Psychology
Division 52 of the American Psychological Association established.
2000
Nobel Prize for nervous system research
The Nobel Prize in Physiology or Medicine jointly awarded to Arvid Carlsson and Paul Greengard (dopamine actions) and Eric R. Kandel (synapses and memory).
2000
Scientists map human genome
World's largest collaborative biological project completes a draft of the genome.
2001
Terrorist attacks in United States
Islamic terrorist group coordinates two attacks (hijacked air carriers) on the United States (New York City, the Pentagon, and a thwarted attempt in Washington, DC).
2002
Nobel Prize for judgment and decision-making research as applied to economic theory
Psychologist Daniel Kahneman jointly receives Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel.
2006
PsycINFO goes digital
Final publication of Psychological Abstracts, bibliographic index to the world's literature in psychology. The print product is continued as the electronic database, PsycINFO.
2013
Fifth edition of the DSM published
American Psychiatric Association revises its classification system for mental disorders and includes diagnostic guidelines based on impairments in functioning and unhealthy (extreme) personality traits.