History of psychology

The history of psychology as a scholarly study of the mind and behavior dates back to the Middle Ages. It was widely regarded to a branch of philosophy until the middle of the 19th-century when psychology developed as an independent scientific discipline in Germany. Psychology borders on various other fields including physiology, neuroscience, artificial intelligence, sociology, and anthropology.

Overview
Philosophical interest in the general set of phenomena currently organized in the West under the label "Psychology" dates back to the ancient civilizations of Egypt, Greece, China and India. These earlier forms of inquiry began adopting what would now be recognized as a more clinical and experimental approach under medieval Muslim psychologists and physicians, whose practitioners built what we would today recognize as psychiatric hospitals. But it was not until the last quarter of the 19th century that the psychology we study today began to be seriously pursued as an independent scientific enterprise.

Psychology as an self-conscious field of experimental study is commonly said to have begun in 1879, when Wilhelm Wundt founded the first laboratory dedicated exclusively to psychological research in Leipzig. Other important early contributors to the field include Hermann Ebbinghaus (a pioneer in studies on memory), William James (the American father of pragmatic psychology), and Ivan Pavlov (who developed the procedures associated with classical conditioning).

Soon after the development of experimental psychology, various kinds of applied psychology began to appear as well. G. Stanley Hall (Johns Hopkins) brought scientific pedagogy to the United States from Germany in the early 1880s. John Dewey's (U. Chicago) educational theory of the 1890s was an early example as well. Also in the 1890s, Hugo Münsterberg (Harvard) began writing about the application of psychology to industry, law, and other professions. Lightner Witmer (U. Pennsylvania) established the first psychological clinic in the 1890s. James McKeen Cattell (Columbia U.) adapted the Francis Galton's anthropometric methods to generate the first program of mental testing in the 1890s as well. In Vienna, meanwhile, the neurologist Sigmund Freud was developing an independent approach to the study of the mind called psychoanalysis that has been widely influential. (Psychoanalysis, which properly belongs in the history of psychiatry, has also had a highly contested relationship with the development of experimental psychology.)

The 20th century saw a reaction against Edward Titchener's skewed interpretation of Wundt's empiricism. This led to the formulation of behaviorism by John B. Watson, which was popularized by B.F. Skinner. Behaviorism proposed epistemologically limiting psychological study to overt behavior, since that could be quantified and easily measured. Scientific knowledge of the "mind" was considered too metaphysical, hence impossible to achieve. The final decades of the 20th century then saw the decline of behaviorism and the rise of a new interdisciplinary approach to studying human psychology, known collectively as cognitive science. Cognitive science again considers the "mind" as a subject for investigation, using the tools of evolutionary psychology, linguistics, computer science, philosophy, and neurobiology. This new form of investigation has proposed that a wide understanding of the human mind is possible, and that such an understanding may be applied to other research domains, such as artificial intelligence.

Early Psychological Thought
Many cultures throughout history have speculated on the nature of the mind, soul, spirit, etc. For instance, in Ancient Egypt, the Edwin Smith Papyrus 1550 BC contains an early description of the brain, and some speculations on its functions (though in a medical/surgical context). Though other medical documents of ancient times were full of incantations and applications meant to turn away disease-causing demons and other superstition, the Edwin Smith Papyrus gives remedies to almost 50 conditions and only 1 contains incantations to ward off evil. It has been praised as being similar to what is today considered common knowledge, but must be recognized as having originated in a very different context.

Ancient Greek philosophers, from Thales (fl. 550 bc) through even to the Roman period, developed an elaborate theory of what they termed the psuchẽ (from which the first half of "psychology" is derived), as well as other (loosely speaking) "psychological" terms -- nous, thumos, logistikon, etc. (see e.g., Everson, 1991; Green & Groff, 2003). The most influential of these are the accounts of Plato (esp. in the Republic -- see e.g., Robinson, 1995) and of Aristotle (esp. Peri Psyches, better known under its Latin title, De Anima -- see e.g., Durrant, 1993; Nussbaum & Rorty, 1992). Hellenistic philosophers (viz., the Stoics and Epicurians) diverged from the Classical Greek tradition in several important ways, especially in their concern with questions of the physiological basis of the mind (see e.g, Annas, 1992). The Roman physician Galen addressed these issues most elaborately and influentially of all. The Greek tradition influenced some Christian and Islamic thought on the topic.

In the Judeo-Christian tradition, the Manual of Discipline (from the Dead Sea Scrolls, ca. 21 BC–61 AD) notes the division of human nature into two temperaments.

In Asia, China had a long history of administering tests of ability as part of its education system. In the 6th century AD, Lin Xie carried out an early experiment, in which he asked people to draw a square with one hand and at the same time draw a circle with the other (ostensibly to test people's vulnerability to distraction).

India, too, had an elaborate theory of "the self" in its Vedanta philosophical writings (see e.g., Paranjpe, 1998).

Medieval Psychological Thought
The first institutions recognizable as psychiatric hospitals and insane asylums were built in the medieval Islamic world in the 8th century: in Baghdad in 705, Fes in the early 8th century, Cairo in 800, and Damascus and Aleppo in 1270. Medieval Muslim physicians also developed practices to treat patients suffering from a variety of ailments related to the mind.

Ahmed ibn Sahl al-Balkhi (850-934) was among the first, in this tradition, to discuss disorders related to both the body and the mind, arguing that "if the nafs [psyche] gets sick, the body may also find no joy in life and may eventually develop a physical illness." Al-Balkhi recognized that the body and the soul can be healthy or sick, or "balanced or imbalanced." He wrote that imbalance of the body can result in fever, headaches and other bodily illnesses, while imbalance of the soul can result in anger, anxiety, sadness and other nafs-related symptoms. He recognized two types of what we now call depression: one caused by known reasons such as loss or failure, which can be treated psychologically; and the other caused by unknown reasons possibly caused by physiological reasons, which can be treated through physical medicine.

In the 1010s, the Iraqi Arab scientist, Ibn al-Haytham (Alhazen) began to intervene in areas related to body and the nafs. In his Book of Optics, for example, he examined visual perception and what we now call sensation, including variations in sensitivity, sensation of touch, perception of colors, perception of darkness, the psychological explanation of the moon illusion, and binocular vision. Al-Biruni also employed such experimental methods in examining reaction time.

Avicenna, similarly, did early work in the treatment of nafs-related illnesses, and developed a system for associating changes in the pulse rate with inner feelings. Avicenna also described phenomena we now recognize as neuropsychiatric conditions, including hallucination, insomnia, mania, nightmare, melancholia, dementia, epilepsy, paralysis, stroke, vertigo and tremor.

Other medieval thinkers who discussed issues related to psychology included: Ibn Zuhr (Avenzoar) described disorders similar to meningitis, intracranial thrombophlebitis, and mediastinal germ cell tumors; Averroes attributed photoreceptor properties to the retina; and Maimonides described rabies and belladonna intoxication.
 * 1) Muhammad, who discussed mental health and mental illness; Ibn Sirin, who wrote a book on dreams and dream interpretation;
 * 2) al-Kindi (Alkindus), who developed forms of psychotherapy and music therapy;
 * 3) Ali ibn Sahl Rabban al-Tabari, clinical psychiatry,
 * 4) al-Farabi (Alpharabius), social psychology and consciousness studies;
 * 5) Ali ibn Abbas al-Majusi (Haly Abbas), neuroanatomy and neurophysiology;
 * 6) Abu al-Qasim al-Zahrawi (Abulcasis), neurosurgery;
 * 7) Abū Rayhān al-Bīrūnī, who described reaction time;
 * 8) and Ibn Tufail, who anticipated the tabula rasa argument and nature versus nurture debate.

The Beginnings of Western Psychology
The influence of Arab and Islamic authors on Western thought through the Renaissance (literally, rebirth) is now becoming recognized. Indeed, it is clear that many of the Ancients' writings would have been lost had it not been for the efforts of the translators in the House of Wisdom, the House of Knowledge, and other such institutions, whose works were later translated into Latin in the 12th century. Yet within the disciplinary lineage, it is not clear how these sources first came to be used. How these works shaped the Psychology that would later emerge, and how they should be cited within that disciplinary narrative, are issues currently under debate.

The Word itself
The first use of the term "psychology" is often attributed to the German scholastic philosopher Rudolf Göckel (1547-1628, often known under the Latin form Rudolph Goclenius), who published the Yucologia hoc est de hominis perfectione, anima, ortu in Marburg in 1590. However, the term seems to have been used more than six decades earlier by the Croatian humanist Marko Marulić (1450-1524) in the title of his Latin treatise, Psichiologia de ratione animae humanae. Although the treatise itself has not been preserved, its title appears in a list of Marulic's works compiled by his younger contemporary, Franjo Bozicevic-Natalis in his "Vita Marci Maruli Spalatensis" (Krstić, 1964). This, of course, may well not have been the very first usage, but it is the earliest documented use at present.

The term did not come into popular usage until the German idealist philosopher, Christian Wolff (1679-1754) used it in his Psychologia empirica and Psychologia rationalis (1732-1734). This distinction between empirical and rational psychology was picked up in Denis Diderot's (1713-1780) Encyclopédie (1751-1784) and was popularized in France by Maine de Biran (1766-1824). In England, the term "psychology" did not overtake "mental philosophy" until the middle of the 19th century, esp. in the work of William Hamilton (1788-1856) (see Danziger, 1997, chap. 3).

Enlightenment Psychological Thought
Early psychology was regarded as the study of the soul (in the Christian sense of the term). The modern philosophical form of psychology was heavily influenced by the works of René Descartes (1596-1650), and the debate that he generated of which the most relevant were the objections to his Meditations on First Philosophy (1641), published with the text. Also important to the later development of psychology were his Passions of the Soul (1649) and Treatise on Man (completed in 1632 but, along with the rest of The World, withheld from publication after Descartes heard of the Catholic Church's condemnation of Galileo; it was eventually published posthumously, in 1664).

Although not educated as a doctor, Descartes did extensive anatomical studies of bull's hearts and was considered important enough for Harvey to respond to. Descartes was one of the first to endorse Harvey's model of the circulation of the blood, but disagreed with his metaphysical framework to explain it. The emergence of psychology as a medical discipline was given a major boost by Thomas Willis', not only in his reference to psychology (the "Doctrine of the Soul") in terms of brain function, but through his detailed 1672 anatomical work, and his treatise "De Anima Brutorum" ("Two Discourses on the Souls of Brutes"). However, Willis acknowledged the influence of Descartes's rival, Pierre Gassendi, as an inspiration for his work.

The philosophers of the British Empiricist and Associationist schools had a profound impact on the later course of experimental psychology. John Locke's An Essay Concerning Human Understanding (1689), George Berkeley's Treatise Concerning the Principles of Human Knowledge (1710), and David Hume's A Treatise of Human Nature (1739-1740) were particularly influential, as were David Hartley's Observations on Man (1749) and John Stuart Mill's A System of Logic. (1843). Also notable was the work of some Continental Rationalist philosophers, especially Baruch Spinoza's (1632-1677) On the Improvement of the Understanding (1662) and Gottfried Wilhelm Leibniz's (1646-1716) New Essays on Human Understanding (completed 1705, published 1765).

The Transition to Psychology
Also influential on the emerging discipline of psychology were debates surrounding the efficacy of Mesmerism (hypnosis) and the value of phrenology. The former was developed in the 1770s by Austrian physician Anton Mesmer (1734-1815) who claimed to use the power of gravity, and later of "animal magnetism," to cure various physical and mental ills. As Mesmer and his treatment became increasingly fashionable in both Vienna and Paris, it also began to come under the scrutiny of suspicious officials. In 1784, an investigation was commissioned in Paris by King Louis which included American ambassador Benjamin Franklin, chemist Antoine Lavoisier and physician Joseph-Ignace Guillotin (later the popularizer of the guillotine). They concluded that Mesmer's method was useless. Although discredited, the "magnetic" tradition continued among Mesmer's students and others, resurfacing in England in the 19th century in the work of physicians John Elliotson (1791-1868), James Esdaile (1808-1859), and James Braid (1795-1860), who renamed it "hypnotism." Mesmerism also continued to have a strong social (if not medical) following in England through the 19th century (see Winter, 1998). In France the practice regained a strong following after it was investigated by the Nancy physician Hippolyte Bernheim (1840-1919) and adopted for the treatment of hysteria by the director of Paris's Salpêtrière Hospital, Jean-Martin Charcot (1825-1893).

Phrenology began as "organology", a theory of brain structure developed by the German physician, Franz Joseph Gall (1758-1828). Gall argued that the brain is divided into a large number of functional "organs," each responsible for particular human mental abilities and dispositions -- hope, love, spirituality, greed, language, the abilities to detect the size, form, and color of objects, etc. He argued that the larger each of these organs are, the greater the power of the corresponding mental trait. Further, he argued that one could detect the sizes of the organs in a given individual by feeling the surface of that person's skull. Gall's ultra-localizationist position with respect to the brain was soon attacked, most notably by French anatomist Pierre Flourens (1794-1867), who conducted ablation studies (on chickens) which purported to demonstrate little or no cerebral localization of function. Although Gall had been a serious (if misguided) researcher, his theory was taken by his assistant, Johann Gaspar Spurzheim (1776-1832), and developed into the profitable, popular enterprise of phrenology, which soon spawned, especially in Britain, a thrinving industry of independent practitioners. In the hands of Scottish religious leader George Combe (1788-1858) (whose book The Constitution of Man was one of the best-sellers of the century), phrenology became strongly associated with political reform movements and egalitarian principles (see, e.g., Shapin, 1975; but also see van Wyhe, 2004). Phrenology soon spread to America as well, where itinerant practical phrenologists assessed the mental well-being of willing customers (see Sokal, 2001).

The Emergence of German Experimental Psychology
Until the middle of the 19th century, psychology was widely regarded as a branch of philosophy. For instance, Immanuel Kant (1724-1804) declared in his Metaphysical Foundations of Natural Science (1786) that a scientific psychology "properly speaking" is impossible. However, Kant proposed what looks to modern eyes very much like an empirical psychology in his Anthropology from a Pragmatic Point of View (1798).

Johann Friedrich Herbart (1776-1841) took issue with Kant's conclusion and attempted to develop a mathematical basis for a scientific psychology. Although he was unable to render his theory empirically testable, his efforts did lead scientists such as Ernst Heinrich Weber (1795-1878) and Gustav Theodor Fechner (1801-1887) to attempt to measure the mathematical relationships between the physical magnitudes of external stimuli and the psychological intensities of the resulting sensations. Fechner (1860) is the originator of the term psychophysics.

Meanwhile, individual differences in reaction time had become a critical issue in the field of astronomy, under the name of the "personal equation". Early researches by Friedrich Wilhelm Bessel (1784-1846) in Königsberg and Adolf Hirsch led to the development of a highly precise chronoscope by Mathias Hipp that, in turn, was based on a design by Charles Wheatstone for a device that measured the speed of artillery shells (Edgell & Symes, 1906). Other timing instruments were borrowed from physiology (e.g., the kymograph) and adapted for use by the Utrecht ophthamologist Franciscus Donders (1818-1899) and his student Johan Jacob de Jaager in measuring the duration of simple mental decisions.

The 19th century was also the period in which physiology, including neurophysiology, professionalized and saw some of its most significant discoveries. Among its leaders were Charles Bell (1774-1843) and François Magendie (1783-1855) who independently discovered the distinction between sensory and motor nerves in the spinal column, Johannes Müller (1801-1855) who proposed the doctrine of specific nerve energies, Emil du Bois-Reymond (1818-1896) who studied the electrical basis of muscle contraction, Pierre Paul Broca (1824-1880) and Carl Wernicke (1848-1905) who identified areas of the brain responsible for different aspects of language, as well as Gustav Fritsch (1837-1927), Eduard Hitzig (1839-1907), and David Ferrier (1843-1924) who localized sensory and motor areas of the brain. One of the principal founders of experimental physiology, Hermann von Helmholtz (1821-1894), conducted studies of a wide range of topics that would later be of interest to psychologists -- the speed of neural transmission, the natures of sound and color, and of our perceptions of them, etc. In the 1860s, while he held a position in Heidelberg, Helmholtz engaged as an assistant a young M.D. named Wilhelm Wundt. Wundt employed the equipment of the physiology laboratory -- chronoscope, kymograph, and various peripheral devices -- to address more complicated psychological questions than had until then been considered experimentally. In particular he was interested in the nature of apperception -- the point at which a perception comes into the central focus of conscious awareness.

In 1874 Wundt took up a professorship in Zurich, where he published his landmark textbook, Grundzüge der physiologischen Psychologie (Principles of Physiological Psychology, 1874). Moving to a more prestigious professorship in Leipzig in 1875, Wundt founded a laboratory specifically dedicated to original research in experimental psychology in 1879, the first laboratory of its kind in the world. In 1883, he launched a journal in which to publish the results of his, and his students', research, Philosophische Studien (Philosophical Studies) (For more on Wundt, see, e.g., Bringmann & Tweney, 1980; Rieber & Robinson, 2001). Wundt attracted a large number of students not only from Germany, but also from abroad. Among his most influential American students were Granville Stanley Hall (who had already obtained a PhD from Harvard under the supervision of William James), James McKeen Cattell (who was Wundt's first assistant), and Frank Angell. The most influential British student was Edward Bradford Titchener (who later became professor at Cornell).

Experimental psychology laboratories were soon also established at Berlin by Carl Stumpf (1848-1936) and at Göttingen by Georg Elias Müller (1850-1934). Another major German experimental psychologist of the era, though he did not direct his own research institute, was Hermann Ebbinghaus (1850-1909).

Experimentation was not the only approach to psychology in the German-speaking world at this time. Starting in the 1890s, employing the case study (traditional in medicine at the time), the Viennese physician Sigmund Freud developed and applied the methods of hypnosis, free association, and dream interpretation to reveal putatively unconscious beliefs and desires that he argued were the underlying causes of his patients' "hysteria." He dubbed this approach psychoanalysis. Freudian psychoanalysis is particularly notable for the emphasis it places on the course of an individual's sexual development in pathogenesis. Psychoanalytic concepts have had a strong and lasting influence on Western culture, particularly on the arts. Although some believe its scientific contribution is still a matter of debate, both Freudian and Jungian psychology's effect on the development of contemporary thought has been the revelation of compartmentalized thinking in which some behavior and thoughts are hidden from consciousness - yet operative as part of the complete personality. Hidden agendas, a bad conscience, or a sense of guilt, are examples of the existence of mental processes in which the individual is not conscious, through choice or lack of understanding, of some aspects of their personality and subsequent behavior.

Psychoanalysis is based in behavioral psychology, a study of mental processes which affect the ego. An understanding of these theoretically allows the individual greater choice and consciousness with a healing effect in neurosis and occasionally in psychosis, both of which Kraft-Ebbing defined as "diseases of the personality". Carl G. Jung, an associate of Freud's who later broke with him over Freud's emphasis on sexuality, was another proponent of behavioral psychology. Working with concepts of the unconscious first noted during the 1800's [John Stuart, Kraft-Ebbing, Janet, Flournoy and others], Jung defined four mental functions which relate to and define the ego, the conscious self. Sensation (which tell consciousness that something is there), feelings (which consist of value judgments, and motivate our reaction to what we have sensed), intellect (an analytic function that compares this event to all known events and gives it a class and category, allowing us to understand a situation within a historical process, personal or public), and intuition (a mental function with access to deep behavioral patterns, intuition can suggest unexpected solutions or predict unforeseen consequences, "as if seeing around corners" as Jung put it). Jung insisted on an empirical psychology in which theories must be based on facts and not on the psychologist's projections or expectations.

Early American Psychology
Around 1875, the Harvard physiology instructor (as he then was), William James, opened a small experimental psychology demonstration laboratory for use with his courses. The laboratory was never used, in those days, for original research, and so controversy remains as to whether it is to be regarded as the "first" experimental psychology laboratory or not. In 1878, James gave a series of lectures at Johns Hopkins University entitled “The Senses and the Brain and their Relation to Thought” in which he argued, contra Thomas Henry Huxley, that consciousness is not epiphenomenal, but must have an evolutionary function, or it would not have been naturally selected in humans. The same year James was contracted by Henry Holt to write a textbook on the "new" experimental psychology. If he had written it quickly, it would have been the first English-language textbook on the topic. It was twelve years, however, before his two-volume Principles of Psychology would be published. In the meantime textbooks were published by George Trumbull Ladd of Yale (1887) and James Mark Baldwin then of Lake Forest College (1889).

In 1879 Charles Sanders Peirce was hired as a philosophy instructor at Johns Hopkins University. Although better known for his astronomical and philosophical work, Peirce also conducted what are perhaps the first American psychology experiments, on the subject of color vision, published in 1877 in the American Journal of Science (see Cadwallder, 1974). Peirce and his student Joseph Jastrow published "On Small Differences in Sensation" in the Memoirs of the National Academy of Sciences, in 1884. In 1882, Peirce was joined at Johns Hopkins by Granville Stanley Hall, who opened the first American research laboratory devoted to experimental psychology in 1883. Peirce was forced out of his position by scandal and Hall was awarded the only professorship in philosophy at Johns Hopkins. In 1887 Hall founded the American Journal of Psychology, which published work primarily emanating from his own laboratory. In 1888 Hall left his Johns Hopkins professorship for the presidency of the newly-founded Clark University, where he remained for the rest of his career.

Soon, experimental psychology laboratories were opened at the University of Pennsylvania (in 1887, by James McKeen Cattell), Indiana University (1888, William Lowe Bryan), the University of Wisconsin-Madison (1888, Joseph Jastrow), Clark University (1889, Edmund Clark Sanford), the McLean Asylum (1889, William Noyes), and the University of Nebraska (1889, Harry Kirke Wolfe).

In 1890, William James' Principles of Psychology finally appeared, and rapidly became the most influential textbook in the history of American psychology. It laid many of the foundations for the sorts of questions that American psychologists would focus on for years to come. The book's chapters on consciousness, emotion, and habit were particularly agenda-setting.

One of those who felt the impact of James' Principles was John Dewey, then professor of philosophy at the University of Michigan. With his junior colleagues, James Hayden Tufts (who founded the psychology laboratory at Michigan) and George Herbert Mead, and his student James Rowland Angell, this group began to reformulate psychology, focusing more strongly on the social environment and on the activity of mind and behavior than the psychophysics-inspired physiological psychology of Wundt and his followers had heretofore. Tufts left Michigan for another junior position at the newly-founded University of Chicago in 1892. A year later, the senior philosopher at Chicago resigned, and Tufts recommended to Chicago president William Rainey Harper that Dewey be offered the position. After initial reluctance, Dewey was hired in 1894. Dewey soon filled out the department with his Michigan companions Mead and Angell. These four formed the core of the Chicago School of psychology.

In 1892, G. Stanley Hall invited 30-some psychologists and philosophers to a meeting at Clark with the purpose of founding a new American Psychological Association (APA). (On the history of the APA, see Evans, Staudt Sexton, & Cadwallader, 1992.) The first annual meeting of the APA was held later that year, hosted by George S. Fullerton at the University of Pennsylvania. Almost immediately tension arose between the experimentally- and philosophically-inclined members of the APA. Edward Bradford Titchener and Lightner Witmer launched an attempt to either establish a separate "Section" for philosophical presentations, or to eject the philosophers altogether. After nearly a decade of debate a Western Philosophical Association was founded and held its first meeting in 1901 at the University of Nebraska. The following year (1902), an American Philosophical Association held its first meeting at Columbia University. These ultimately became the Central and Eastern Divisions of the modern American Philosophical Association.

In 1894, a number of psychologists, unhappy with the parochial editorial policies of the American Journal of Psychology approached Hall about appointing an editorial board and opening the journal out to more psychologists not within Hall's immediate circle. Hall refused, so James McKeen Cattell (then of Columbia) and James Mark Baldwin (then of Princeton) co-founded a new journal, Psychological Review, which rapidly grew to become a major outlet for American psychological researchers.

Beginning in 1895, James Mark Baldwin (Princeton) and Edward Bradford Titchener (Cornell) entered into an increasingly acrimonious dispute over the correct interpretation of some anomalous reaction time findings that had come from the Wundt laboratory (originally reported by Ludwig Lange and James McKeen Cattell). In 1896, James Rowland Angell and Addison W. Moore (Chicago) published a series of experiments in Psychological Review appearing to show that Baldwin was the more correct of the two. However, they interpreted their findings in light of John Dewey's new approach to psychology, which rejected the traditional stimulus-response understanding of the reflex arc in favor of a "circular" account in which what serves as "stimulus" and what as "response" depends on how one views the situation. The full position was laid out in Dewey's landmark article "The Reflex Arc Concept in Psychology" which also appeared in Psychological Review in 1896.

Titchener responded in Philosophical Review (1898, 1899) by distinguishing his austere "structural" approach to psychology from what he termed the Chicago group's more applied "functional" approach, and thus began the first major theoretical rift in American psychology between Structuralism and Functionalism. The group at Columbia, led by James McKeen Cattell, Edward L. Thorndike, and Robert S. Woodworth, was often regarded as a second (after Chicago) "school" of American Functionalism (see, e.g., Heidbredder, 1933), although they never used that term themselves, because their research focused on the applied areas of mental testing, learning, and education. Dewey was elected president of the APA in 1899, while Titchener dropped his membership in the association. (In 1904, Titchener formed his own group, eventually known as the Society of Experimental Psychologists.) Jastrow promoted the functionalist approach in his APA presidential address of 1900, and Angell adopted Titchener's label explicitly in his influential textbook of 1904 and his APA presidential address of 1906. In reality, Structuralism was, more or less, confined to Titchener and his students. Functionalism, broadly speaking, with its more practical emphasis on action and application, better suited the American cultural "style" and, perhaps more important, was more popular among university trustees and private funding agencies.

Early French Psychology
In no small measure because of the conservatism of the reign of Louis Napoléon (president, 1848-1852; emperor as "Napoléon III," 1852-1870), academic philosophy in France through the middle part of the 19th century was controlled by members of the eclectic and spiritualist schools, led by figures such as Victor Cousin (1792-1867), Théodore Jouffroy (1796-1842), and Paul Janet (1823-1899). These were traditional metaphysical schools, opposed to regarding psychology as a natural science. With the ouster of Napoléon III after the débacle of the Franco-Prussian war, new paths, both political and intellectual, became possible. From the 1870 forward, a steadily increasing interest in positivist, materialist, evolutionary, and deterministic approaches to psychology developed, influenced by, among others, the work of Hyppolyte Taine (1828-1893) (e.g., De L'Intelligence, 1870) and Théodule Ribot (1839-1916) (e.g., La Psychologie Anglaise Contemporaine, 1870). In 1876, Ribot founded Revue Philosophique (the same year as Mind was founded in Britain), which for the next generation would be virtually the only French outlet for the "new" psychology (Plas, 1997). Although not a working experimentalist himself, Ribot's many books were to have profound influence on the next generation of psychologists. These included especially his L'Hérédité Psychologique (1873) and La Psychologie Allemande Contemporaine (1879). In the 1880s, Ribot's interests turned to psychopathology, writing books on disorders of memory (1881), will (1883), and personality (1885), and where he attempted to bring to these topics the insights of general psychology. Although in 1881 he lost a Sorbonne professorship in the History of Psychological Doctrines to traditionalist Jules Soury (1842-1915), from 1885 to 1889 he taught experimental psychology at the Sorbonne. In 1889 he was awarded a chair at the Collège de France in Experimental and Comparative Psychology, which he held until 1896 (Nicolas, 2002).

France's primary psychological strength lay in the field of psychopathology. The chief neurologist at the Salpêtrière Hospital in Paris, Jean-Martin Charcot (1825-1893), had been using the recently revivied and renamed (see above) practice of hypnoisis to "experimentally" produce hysterical symptoms in some of his patients. Two of his students, Alfred Binet (1857-1911) and Pierre Janet (1859-1947), adopted and expanded this practice in their own work.

In 1889, Binet and his colleague Henri Beaunis (1830-1921) co-founded, at the Sorbonne, the first experimental psychology laboratory in France. Just five years later, in 1894, Beaunis, Binet, and a third colleague, Victor Henri (1872-1940), co-founded the first French journal dedicated to experimental psychology, L'Année Psychologique. In the first years of the 20th century, Binet was requested by the French government to develop a method for the newly-founded universal public education system to identify students who would require extra assistance to master the standardized curriculum. In response, with his collaborator Théodore Simon (1873-1961), he developed the Binet-Simon Intelligence Test, first published in 1905 (revised in 1908 and 1911).

Although the test was used to effect in France, it would find its greatest success (and controversy) in the United States, where it was translated in by Henry H. Goddard (1866-1957), the director of the Training School for the Feebleminded in Vineland, New Jersey, and his assistant, Elizabeth Kite (a translation of the 1905 edition appeared in the Vineland Bulletin in 1908, but much better known was Kite's 1916 translation of the 1908 edition, which appeared in book form). The translated test was used by Goddard to advance his eugenics agenda with respect to those he deemed congenitally feeble-minded, especially immigrants from non-Western European countries. Binet's test was revised by Stanford professor Lewis M. Terman (1877-1956) into the Stanford-Binet IQ test in 1916.

With Binet's death in 1911, the Sorbonne laboratory and L'Année Psychologique fell to Henri Piéron (1881-1964). Piéron's orientation was more physiological that Binet's had been.

Pierre Janet became the leading psychiatrist in France, being appointed to the Salpêtrière (1890-1894), the Sorbonne (1895-1920), and the Collège de France (1902-1936). In 1904, he co-founded the Journale de Psychologie Normale et Pathologique with fellow Sorbonne professor Georges Dumas (1866-1946), a student and faithful follower of Ribot. Whereas Janet's teacher, Charcot, had focused on the neurologial bases of hysteria, Janet was concerned to develop a scientific approach to psychopathology as a mental disorder. His theory that mental pathology results from conflict between unconscious and conscious parts of the mind, and that unconscious mental contents may emerge as symptoms with symbolic meanings led to a public priority dispute with Sigmund Freud.

Early British Psychology
Although the British had the first scholarly journal dedicated to the topic of psychology -- Mind, founded in 1876 by Alexander Bain and edited by George Croom Robertson -- it was quite a long while before experimental psychology developed there to challenge the strong tradition of "mental philosophy." The experimental reports that appeared in Mind in the first two decades of its existence were almost entirely authored by Americans, especially G. Stanley Hall and his students (notably Henry Herbert Donaldson) and James McKeen Cattell.

Francis Galton's (1822-1911) anthropometric laboratory opened in 1884. There people were tested on a wide variety of physical (e.g., strength of blow) and percepetual (e.g., visual acuity) attributes. In 1886 Galton was visited by James McKeen Cattell who would later adapt Galton's techniques in developing his own mental testing research program in the United States. Galton was not primarily a psychologist, however. The data he accumulated in the anthropometric laboratory primarily went toward supporting his case for eugenics. To help interpret the mounds of data he accumulated, Galton developed a number of important statistical techniques, including the precursors to the scatterplot and the product-moment correlation coefficient (later perfected by Karl Pearson, 1857-1936).

Soon after, Charles Spearman (1863-1945) developed the correlation-based statistical procedure of factor analysis in the process of building a case for his two-factor theory of intelligence, published in 1901. Spearman believed that people have an inborn level of general intelligence or g which can be crystallized into a specific skill in any of a number of narrow content area (s, or specific intelligence).

Laboratory psychology of the kind practiced in Germany and the United States was slow in coming to Britain. Although the philosopher James Ward (1843-1925) urged Cambridge University to establish a psychophysics laboratory from the mid-1870s forward, it was not until the 1891 that they put so much as £50 toward some basic apparatus (Bartlett, 1937). A laboratory was established through the assistance of the physiology department in 1897 and a lectureship in psychology was established which first went to W. H. R. Rivers (1864-1922). Soon Rivers was joined by C. S. Myers (1873-1946) and William McDougall (1871-1938). This group showed as much interest in anthropology as psychology, going with Alfred Cort Haddon (1855-1940) on the famed Torres Straits expedition of 1898.

In 1901 the Psychological Society was established (which renamed itself the British Psychological Society in 1906), and in 1904 Ward and Rivers co-founded the British Journal of Psychology.

Würzburg School
In 1896, one of Wundt's former Leipzig laboratory assistants, Oswald Külpe (1862-1915), founded a new laboratory in Würzburg. Külpe soon surrounded himself with a number of younger psychologists, most notably Narziß Ach (1871-1946), Karl Bühler (1879-1963), Ernst Dürr (1878-1913), Karl Marbe (1869-1953), and Henry Jackson Watt (1879-1925). Collectively, they developed a new approach to psychological experimentation that flew in the face of many of Wundt's restrictions. Wundt had drawn a distinction between the old philosophical style of self-observation (Selbstbeobachtung) in which one introspected for extended durations on higher thought processes and inner-perception (innere Wahrnehmung) in which one could be immediately aware of a momentary sensation, feeling, or image (Vorstellung). The former was declared to be impossible by Wundt, who argued that higher thought could not be studied experimentally through extended introspection, but only humanistically through Völkerpsychologie (folk psychology). Only the latter was a proper subject for experimentation.

The Würzburgers, by contrast, designed experiments in which the experimental subject was presented with a complex stimulus (e.g., a Nietzschean aphorism or a logical problem) and after processing it for a time (e.g., interpreting the aphorism or solving the problem), retrospectively reported to the experimenter all that had passed through his consciousness during the interval. In the process, the Würzburgers claimed to have discovered a number of new elements of consciousness (over and above Wundt's sensations, feelings, and images) including Bewußtseinslagen (conscious sets), Bewußtheiten (awarenesses), and Gedanken (thoughts). In the English-language literature, these are often collectively termed "imageless thoughts," and the debate between Wundt and the Würzburgers as the "imageless thought controversy."

Wundt referred to the Würzburgers' studies as "sham" experiments and criticized them vigorously. Wundt's most significant English student, Edward Bradford Titchener, then working at Cornell, intervened in the dispute, claiming to have conducted extended introspective studies in which he was able to resolve the Würzburgers imageless thoughts into sensations, feelings, and images. He thus, paradoxically, used a method of which Wundt did not approve in order to affirm Wundt's view of the situation (see Kusch, 1995; Kroker, 2003).

The imageless thought debate is often said to have been instrumental in undermining the legitimacy of all introspective methods in experimental psychology and, ultimately, in bringing about the behaviorist revolution in American psychology. It was not without its own delayed legacy, however. Herbert Simon cites the work of one Würzburg psychologists in particular, Otto Selz (1881-1943), for having inspired him to develop his famous problem-solving computer algorithms (e.g., Logic Theorist and General Problem Solver) and his "thinking out loud" method for protocol analysis. In addition, Karl Popper studied psychology under Bühler and Selz, and appears to have brought some of their influence, unattributed, to his philosophy of science (Ter Hark, 2004).

Gestalt Psychology
(This section adapted from Green, 2000, by permission of the author.)

Whereas the Würzburgers debated with Wundt mainly on matters of method, another German movement, centered in Berlin, took issue with the widespread assumption that the aim of psychology should be to break consciousness down into putative basic elements. Instead, they argued that the psychological "whole" has priority and that the "parts" are defined by the structure of the whole, rather than vice versa. Thus, the school was named Gestalt, a German term meaning approximately "form" or "configuration." It was led by Max Wertheimer (1880-1943), Wolfgang Köhler (1887-1967), and Kurt Koffka (1886-1941). Wertheimer had been a student of Austrian philosopher, Christian von Ehrenfels (1859-1932), who claimed that in addition to the sensory elements of a perceived object, there is an extra element which, though in some sense derived from the organization of the standard sensory elements, is also to be regarded as being an element in its own right. He called this extra element Gestalt-qualität or "form-quality." For instance, when one hears a melody, one hears the notes plus something in addition to them which binds them together into a tune -- the Gestalt-qualität. It is the presence of this Gestalt-qualität which, according to Von Ehrenfels, allows a tune to be transposed to a new key, using completely different notes, but still retain its identity. Wertheimer took the more radical line that "what is given me by the melody does not arise ... as a secondary process from the sum of the pieces as such. Instead, what takes place in each single part already depends upon what the whole is," (1925/1938). In other words, one hears the melody first and only then may perceptually divide it up into notes. Similarly in vision, one sees the form of the circle first -- it is given "im-mediately" (i.e. its apprehension is not mediated by a process of part-summation). Only after this primary apprehension might one notice that it is made up of lines or dots or stars.

Gestalt-Theorie was officially initiated in 1912 in an article by Wertheimer on the phi-phenomenon; a perceptual illusion in which two stationary but alternately flashing lights appear to be a single light moving from one location to another. Contrary to popular opinion, his primary target was not behaviorism, as it was not yet a force in psychology. The aim of his criticism was, rather, the atomistic psychologies of Hermann von Helmholtz (1821-1894), Wilhelm Wundt (1832-1920), and other European psychologists of the time.

The two men who served as Wertheimer's subjects in the phi experiment were Köhler and Koffka. Köhler was an expert in physical acoustics, having studied under physicist Max Planck (1858-1947), but had taken his degree in psychology under Carl Stumpf (1848-1936). Koffka was also a student of Stumpf's, having studied movement phenomena and psychological aspects of rhythm. In 1917 Köhler (1917/1925) published the results of four years of research on learning in chimpanzees. Köhler showed, contrary to the claims of most other learning theorists, that animals can learn by "sudden insight" into the "structure" of a problem, over and above the associative and incremental manner of learning that Ivan Pavlov (1849-1936) and Edward Lee Thorndike (1874-1949) had demonstrated with dogs and cats, respectively.

The terms "structure" and "organization" were focal for the Gestalt psychologists. Stimuli were said to have a certain structure, to be organized in a certain way, and that it is to this structural organization, rather than to individual sensory elements, that the organism responds. When an animal is conditioned, it does not simply respond to the absolute properties of a stimulus, but to its properties relative to its surroundings. To use a favorite example of Köhler's, if conditioned to respond in a certain way to the lighter of two gray cards, the animal generalizes the relation between the two stimuli rather than the absolute properties of the conditioned stimulus: it will respond to the lighter of two cards in subsequent trials even if the darker card in the test trial is of the same intensity as the lighter one in the original training trials.

In 1921 Koffka published a Gestalt-oriented text on developmental psychology, Growth of the Mind. With the help of American psychologist Robert Ogden, Koffka introduced the Gestalt point of view to an American audience in 1922 by way of a paper in Psychological Bulletin. It contains criticisms of then-current explanations of a number of problems of perception, and the alternatives offered by the Gestalt school. Koffka moved to the United States in 1924, eventually settling at Smith College in 1927. In 1935 Koffka published his Principles of Gestalt Psychology. This textbook laid out the Gestalt vision of the scientific enterprise as a whole. Science, he said, is not the simple accumulation of facts. What makes research scientific is the incorporation of facts into a theoretical structure. The goal of the Gestaltists was to integrate the facts of inanimate nature, life, and mind into a single scientific structure. This meant that science would have swallow not only what Koffka called the quantitative facts of physical science but the facts of two other "scientific categories": questions of order and questions of Sinn, a German word which has been variously translated as significance, value, and meaning. Without incorporating the meaning of experience and behavior, Koffka believed that science would doom itself to trivialities in its investigation of human beings.

Having survived the onslaught of the Nazis up to the mid-1930s (see Henle, 1978), all the core members of the Gestalt movement were forced out of Germany to the United States by 1935 (Henle, 1984). Köhler published another book, Dynamics in Psychology, in 1940 but thereafter the Gestalt movement suffered a series of setbacks. Koffka died in 1941 and Wertheimer in 1943. Wertheimer's long-awaited book on mathematical problem-solving, Productive Thinking was published posthumously in 1945 but Köhler was now left to guide the movement without his two long-time colleagues. (For more on the history of Gestalt psychology, see Ash, 1995.)

The Emergence of Behaviorism in America
As a result of the conjunction of a number of events in the early 20th century, behaviorism gradually emerged as the dominant school in American psychology. First among these was the increasing skepticism with which many viewed the concept of consciousness: although still considered to be the essential element separating psychology from physiology, its subjective nature and the unreliable introspective method it seemed to require, troubled many. William James' 1904 Journal of Philosophy... article "Does Consciousness Exist?", laid out the worries explicitly.

Second was the gradual rise of a rigorous animal psychology. In addition to Edward Lee Thorndike's work with cats in puzzle boxes in 1898, the start of research in which rats learn to navigate mazes was begun by Willard Small (1900, 1901 in American Journal of Psychology). Robert M. Yerkes's 1905 Journal of Philosophy... article "Animal Psychology and the Criteria of the Psychic" raised the general question of when one is entitled to attribute consciousness to an organism. The following few years saw the emergence of John Broadus Watson (1878-1959) as a major player, publishing his dissertation on the relation between neurological development and learning in the white rat (1907, Psychological Review Monograph Supplement; Carr & Watson, 1908, J. Comparative Neurology & Psychology). Another important rat study was published by Henry H. Donaldson (1908, J. Comparative Neurology & Psychology). The year 1909 saw the first English-language account of Ivan Pavlov's studies of conditioning in dogs (Yerkes & Morgulis, 1909, Psychological Bulletin).

A third factor was the rise of Watson to a position of significant power within the psychological community. In 1908, Watson was offered a junior position at Johns Hopkins by James Mark Baldwin. In addition to heading the Johns Hopkins department, Baldwin was the editor of the influential journals, Psychological Review and Psychological Bulletin. Only months after Watson's arrival, Baldwin was forced to resign his professorship due to scandal. Watson was suddenly made head of the department and editor of Baldwin's journals. He resolved to use these powerful tools to revolutionize psychology in the image of his own research. In 1913 he published in Psychological Review the article that is often called the "manifesto" of the behaviorist movement, "Psychology as the Behaviorist Views It." There he argued that psychology "is a purely objective experimental branch of natural science", "introspection forms no essential part of its methods..." and "The behaviorist... recognizes no dividing line between man and brute". The following year, 1914, his first textbook, Behavior went to press. Although behaviorism took some time to be accepted as a comprehensive approach (see Samelson, 1981), (in no small part because of the intervention of World War I), by the 1920s Watson's revolution was well underway. The central tenet of early behaviorism was that psychology should be a science of behavior, not of the mind, and rejected internal mental states such as beliefs, desires, or goals. Watson himself, however, was forced out of Johns Hopkins by scandal in 1920. Although he continued to publish during the 1920s, he eventually moved on to a career in advertising (see Coon, 1994).

Among the behaviorists who continued on, there were a number of disagreements about the best way to proceed. Neo-behaviorists such as Edward C. Tolman, Edwin Guthrie, Clark L. Hull, and B. F. Skinner debated issues such as (1) whether to reformulate the traditional psychological vocabulary in behavioral terms or discard it in favor of a wholly new scheme, (2) whether learning takes place all at once or gradually, (3) whether biological drives should be included in the new science in order to provide a "motivation" for behavior, and (4) to what degree any theoretical framework is required over and above the measured effects of reinforcement and punishment on learning. By the late 1950s, Skinner's formulation had become dominant, and it remains a part of the modern discipline under the rubric of Behavior Analysis.

Behaviorism was the ascendant experimental model for research in psychology for much of the 20th century, largely due to the creation and successful application (not least of which in advertising) of conditioning theories as scientific models of human behaviour.

Genevan School
In 1918, Jean Piaget (1896-1980) turned away from his early training in Natural History and began post-doctoral work in psychoanalysis in Zurich. In 1919, he moved to Paris to work at the Binet-Simon Lab. However, Binet had died in 1911 and Simon lived and worked in Rouen. His supervision therefore came (indirectly) from Pierre Janet, Binet's old rival and a professor at the College de France.

The job in Paris was relatively simple: to use the statistical techniques he had learned as a natural historian, studying molluscs, to standardize Cyril Burt's intelligence test for use with French children. Yet without direct supervision, he soon found a remedy to this boring work: exploring why children made the mistakes they did. Applying his early training in psychoanalytic interviewing, Piaget began to intervene directly with the children: "Why did you do that?" (etc.) It was from this that the ideas formalized in his later stage theory first emerged.

In 1921, Piaget moved to Geneva to work with Edouard Claparède at the Rousseau Institute.

In 1936, Piaget received his first honorary doctorate from Harvard.

In 1955, the International Center for Genetic Epistemology was founded: an interdisciplinary collaboration of theoreticians and scientists, devoted to the study of topics related to Piaget's theory.

In 1968, Piaget received the "distinguished scientific contributions" award from the American Psychological Association.

Cognitivism
Noam Chomsky's (1957) review of Skinner's book Verbal Behavior (that aimed to explain language acquisition in a behaviorist framework) is considered one of the major theoretical challenges to the type of radical behaviorism that Skinner taught. Chomsky showed that language could not be learned solely from the sort of operant conditioning that Skinner postulated. Chomsky's argument was that as people could produce an infinite variety of sentences unique in structure and meaning, and that these could not possibly be generated solely through experience of natural language. As an alternative, he concluded that there must be internal mental structures - states of mind of the sort that behaviorism rejected as illusory. Similarly, work by Albert Bandura showed that children could learn by social observation, without any change in overt behaviour, and so must be accounted for by internal representations.

The rise of computer technology also promoted the metaphor of mental function as information processing. This, combined with a scientific approach to studying the mind, as well as a belief in internal mental states, led to the rise of cognitivism as the dominant model of the mind.

Links between brain and nervous system function were also becoming common, partly due to the experimental work of people like Charles Sherrington and Donald Hebb, and partly due to studies of people with brain injury (see cognitive neuropsychology). With the development of technologies for accurately measuring brain function, neuropsychology and cognitive neuroscience have become some of the most active areas in contemporary psychology.

With the increasing involvement of other disciplines (such as philosophy, computer science, and neuroscience) in the quest to understand the mind, the umbrella discipline of cognitive science has been created as a means of focusing such efforts in a constructive way.

Dissenting schools
Not all psychologists, however, have been happy with what they perceive as mechanical models of the mind and human nature.

Carl Jung, a one-time follower and contemporary of Freud, was instrumental in introducing notions of spirituality into Freudian psychoanalysis (Freud had rejected religion as a mass delusion).

Alfred Adler, after a brief association with Freud's discussion circle, left to form his own discipline, called Individual (indivisible) Psychology. His influence on contemporary psychology has been considerable, with many approaches borrowing fragments of his theory. A recent rebirth of his legacy, Classical Adlerian Psychology, combines Adler's original theory of personality, style of psychotherapy, and philosophy of living, with Abraham Maslow's vision of optimal functioning.

Humanistic psychology emerged in the 1950s and has continued as a reaction to positivist and behaviorist approaches to the mind. It stresses a phenomenological view of human experience and seeks to understand human beings and their behavior by conducting qualitative research. The humanistic approach has its roots in existentialist and phenomenological philosophy and many humanist psychologists completely reject a scientific approach, arguing that trying to turn human experience into measurements strips it of all meaning and relevance to lived existence.

Some of the founding theorists behind this school of thought are Abraham Maslow, who formulated a hierarchy of human needs; Carl Rogers, who created and developed client centred therapy; and Fritz Perls, who helped create and develop Gestalt therapy.

A further development of Humanistic psychology emerging in the 1970s was Transpersonal psychology, which studies the spiritual dimension of humanity, looking at the possibilities for development beyond the normal ego-boundaries.

Scholarly Journals

 * History of Psychology
 * For more information, including rejection rates and average publication lag, see this report


 * History of the Human Sciences


 * Journal of the History of the Behavioral Sciences

Scholarly Societies & Associations

 * Cheiron: The International Soceity for the History of Behavioral & Social Sciences


 * European Society for the History of the Human Sciences


 * Forum for the History of Human Science


 * History & Philosophy Section of the British Psychological Society


 * History & Philosophy of Psychology Section of the Canadian Psychological Association


 * Society for the History of Psychology (American Psychological Association Division 26)

E-Textbooks

 * The History of Psychology - e-text about the historical and philosophical background of psychology by C. George Boeree


 * Mind and Body: René Descartes to William James e-text by Robert H. Wozniak

Collections of Primary Source Texts

 * Classics in the History of Psychology - on-line full texts of 250+ historically-significant primary source articles, chapters, & books, ed. by Christopher D. Green


 * Fondation Jean Piaget - Collection of primary sources by, and secondary sources about, Jean Piaget (in French; edited by Jean-Jacques Ducret and Wolfgang Schachner)


 * The Mead Project - collection of writings by George Herbert Mead and other related thinkers (e.g., Dewey, James, Baldwin, Cooley, Veblen, Sapir), ed. by Lloyd Gordon Ward and Robert Throop


 * Sir Francis Galton, F.R.S.


 * William James Site ed. by Frank Pajares


 * History of Phrenology on the Web ed. by John van Wyhe

Collections of Secondary Scholarship on the History of Psychology

 * History & Theory of Psychology Eprint Archive - Open access on-line depository of articles on the history & theory of psychology
 * Advances in the History of Psychology - Blog edited by Jeremy Burman of York University (Toronto, Canada), advised by Christopher D. Green

Websites of Physical Archives

 * The Archives of the History of American Psychology - Large collection of documents and objects at the University of Akron, directed by David Baker


 * Archives of the American Psychological Association directed by Wade Pickren

Multimedia Resources

 * An Academy in Crisis: The Hiring of James Mark Baldwin and James Gibson Hume at the University of Toronto in 1889 - 40-min. video documentary by Christopher D. Green


 * Toward a School of Their Own: The Prehistory of American Functionalist Psychology - 64-min. video documentary by Christopher D. Green


 * This Week in the History of Psychology - 30-episode podcast series by Christopher D. Green

تاريخ علم النفس Geschichte der Psychologie Chronologie de l'histoire de la psychologie Storia della psicologia Geschiedenis van de psychologie Dejiny psychológie

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