Experimental psychology

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Experimental psychology (also experimental psychology ) is the branch of psychological research that primarily uses experiments as a scientific method (see psychological experiment ).


Stimulated by physiological experiments, for example by Ernst Heinrich Weber , the experiment was transferred to psychology on a larger scale in the mid-19th century, mainly under the influence of Gustav Theodor Fechner ( psychophysics ), Hermann Ludwig von Helmholtz ( sensory physiology ) and generally as experimental psychology introduced by Wilhelm Wundt . Wundt founded the first psychological laboratory with an experimental psychological research program in Leipzig in 1879 . In addition to psychophysics, the feelings and volitional activity associated with sensory perception, i.e. the entire process of apperception , were also included here.

Wundt's lectures and laboratory were attended by students and guests from all over the world. Many of his assistants and temporary employees belong to the founding generation of psychology as a scientific discipline. Sun founded Benjamin Bourdon (1860-1943), a French student of Wundt, 1896 a psychological laboratory in Rennes , Victor Henri (1872-1940) worked in Paris under the direction of Alfred Binet in 1895 after training in Wundt. Even Stanley Hall (1844-1924) spent two years in Leipzig and established the first psychological laboratory of the United States at the Johns Hopkins University in Baltimore from 1882. There was his successor John B. Watson (1878-1958), the founder of behaviorism . Wundt's first assistant, James McKeen Cattell (1860–1944), became the first psychology professor in the United States in 1888. The American Lightner Witmer (February 1891-late 1892 in Leipzig, received his doctoral diploma from Wundt) opened the first psychological clinic at the University of Pennsylvania in 1896 with the intention of observing children who showed either learning difficulties or behavioral problems. Another student of Wundt was the founder of structuralism , Edward Bradford Titchener (1867-1927). Even Emil Kraepelin (1856-1926), the pioneer of modern psychiatry , met in Leipzig, the methods of experimental psychology. In 1887 Oswald Külpe received his doctorate and a year later he completed his habilitation with “The Doctrine of Will in Modern Philosophy”; 1887-94 he was an assistant. However , he later went his own way with the “ Würzburg School ”.

Towards the end of the 19th century, the Leipzig Institute and the other institutes at German universities that had since emerged were internationally known. Wundt was famous as the founding father, but his reputation declined around the turn of the century, as an examination of the reception of his works shows. Other people and other directions gained more influence. At the turn of the century, professional societies were founded in several European countries, for example the German Society for Experimental Psychology in 1904, although non-experimental work also appeared at its congresses from the start. This society was later expanded to become the German Society for Psychology . Since then, experimentally oriented psychology has been a mainstream within psychology as a methodology and program.

Definition of the psychological experiment

The most important method in the initial phase was, as in psychophysics , the trained self- observation carried out under experimentally controlled conditions , which Wundt emphatically differentiated from untrained (“naive”) introspection and personal everyday experience. Wundt only saw suitable methods of experimental psychology in this experimentally controlled self-observation and in the recording of objective reactions and physiological changes .

Wundt defined the typical psychological experiment

“(1) The observer must possibly be able to determine the occurrence of the process to be observed himself.

(2) The observer must, as far as possible, grasp the phenomena in a state of tense attention and follow their course.

(3) It must be possible to repeat each observation several times under the same circumstances in order to secure the results.

(4) The conditions under which the phenomenon occurs must be determined by varying the accompanying circumstances and, once they have been determined, be systematically changed in the various associated experiments, sometimes completely eliminating them in individual experiments, sometimes in their strength or Quality. "

In a controversy with Karl Bühler , Wundt sharply rejected Bühler's psychological investigations as "questioning experiments" because the (free) introspective reports required change the current thinking process by verbalizing it. In contrast, Wundt saw his linguistic psychology as an adequate way of thinking psychological research. Bühler's research amounts to uncertain and random information, and it lacks repeatability.

More recent textbooks give definitions that follow on from Wundt, but contain further definition features and distinctions (see psychological experiment ).


Wundt saw an essential role model in the scientific experiment . Empirical psychology should orient itself towards this strategic concept and examine how far it leads. In addition, Wundt used other methods such as generalizing comparison and developed the first doctrine of psychological interpretation . The title of his best-known book Grundzüge der Physiologische Psychologie (1974) was not infrequently misunderstood. Wundt does not strive to reduce psychological to brain-physiological processes, but rather determines the categorical independence of the consciousness processes. According to Wundt, the psychological experiment is only suitable for some areas of psychological research.

Fundamental criticism of the intention to carry out experimental investigations into psychic phenomena was already expressed by Immanuel Kant . He emphasized that psychological processes are changed through observation , i.e. through the investigation methodology (see reactivity (social sciences) ) and he denied the measurability of psychological processes ( psychometry ).

When discussing the concept of experimental psychology, the respective narrower and broader definitions of the experiment must be differentiated and the epistemological framework and one's own point of view must be explicitly explained and taken into account (see category , naturalism , perspectivism , pluralism , reductionism ). The long-standing controversial question of whether psychology can be described as a natural science or a humanities and social science has several aspects and concerns basic theoretical assumptions as well as details of the methodology of psychology.

Psychological experimental research has a special position because a voluntarily participating and self-confident person, an experiencing subject, fulfills certain tasks in the role of a test subject on the basis of a psychological instruction under the artificial conditions of a laboratory or another standardized situation. A strictly scientific experimental work is probably only possible in the areas bordering on physiology , in sub-areas of biological psychology and in animal psychology or behavioral research.

The controversies have lost their sharpness since the more recent epistemological discussion has shown the fundamental importance of theoretical assumptions and conventions and has shown how questionable the assertion of a verifiable psychological fact ( fact ) is. In the place of the demanding terms causal explanation and law in scientific psychology, more modest terms of statistical laws and statistical expectations have emerged (Westermann, 2000). Nevertheless, the conception of experimental psychology is linked to the expectation of an elaborated methodology for testing hypotheses and collecting data under as largely controlled conditions as possible (cf. psychological experiment ). This methodology is taught in the specialist course in order to promote method-critical thinking and to counter a speculative psychologization.

In addition to (in a broad sense) experimental psychology, there are other research strategies and practical investigation methods : above all, differential psychological diagnostics and test methods , interviews and questionnaires , surveys and observational studies (external observation), with statistical evaluations often being carried out.

In a generalizing way, the experimental-statistical paradigm can be contrasted with an interpretive paradigm. The various directions of qualitative psychology (formerly mostly referred to as understanding psychology or phenomenologically oriented psychology) as well as psychoanalysis and related directions are based essentially on psychological interpretation .


  • Jürgen Bortz, Nicola Döring: Research methods and evaluation for human and social scientists 4th edition. Springer, Heidelberg 2006, ISBN 3-540-33305-3 .
  • Markus A. Wirtz (Ed.): Dorsch - Lexicon of Psychology. 16th edition. Huber, Bern 2013, ISBN 978-3-456-85234-8 .
  • Jochen Fahrenberg: Wilhelm Wundt - pioneer of psychology and outsider? Guiding principles of the science concept and its reception history. e-book, 2011.
  • Oswald Huber: The Psychological Experiment. An introduction. 4th edition. Huber, Bern 2005, ISBN 3-456-84201-5 .
  • Siegbert Reiss, Viktor Sarris: Experimental psychology: from theory to practice. Pearson, Munich 2012, ISBN 978-3-86894-147-0 .
  • Viktor Sarris: Methodological foundations of experimental psychology. Volume 1: Knowledge acquisition and methodology . Reinhardt, Munich 1990, ISBN 3-497-01111-8 . Volume 2: Design of experiments and stages of the psychological experiment . Reinhardt, Munich 1992, ISBN 3-497-01112-6 .
  • Wolfgang Schönpflug: History and systematics of psychology. A textbook for undergraduate studies. 2nd Edition. Psychologie Verlag Union, Weinheim 2004, ISBN 3-621-28065-0 .
  • Thomas Sturm: Kant and the human sciences . mentis, Paderborn 2009, ISBN 978-3-89785-608-0 .
  • Harald Walach: Psychology. Theory of Science, Philosophical Foundations and History. 3. Edition. Kohlhammer, Stuttgart 2013, ISBN 978-3-17-022937-2 .
  • Rainer Westermann: Theory of Science and Experimental Methodology. A textbook on psychological methodology. Hogrefe, Göttingen 2000, ISBN 3-8017-1090-4 .

Individual evidence

  1. Wolfgang Schönpflug: History and systematics of psychology . 2004.
  2. ^ Jochen Fahrenberg: Wilhelm Wundt - pioneer of psychology and outsider? Guiding principles of the science concept and its reception history. e-book, 2011. [1]
  3. Wilhelm Wundt : About questioning experiments and about the methods of the psychology of thinking. In: Psychological Studies. Volume 3, 1907, pp. 301-360.
  4. Christina Massen, Jürgen Bredenkamp: The Wundt-Bühler controversy from the point of view of today's cognitive psychology. In: Journal of Psychology. Volume 213, 2005, pp. 109-114.
  5. Wilhelm Wundt: Critical gleanings on the questioning method. In: Archives for the whole of psychology. Volume 11, 1908, pp. 445-459.
  6. ^ Jochen Fahrenberg: Wilhelm Wundts philosophy of science. An attempt at reconstruction. In: Psychological Rundschau. Volume 63 (4), 2012, pp. 228-238.
  7. Jochen Fahrenberg: On the theory of categories in psychology. Complementarity principle. Perspectives and change of perspective. Pabst Science Publishers, Lengerich 2013, ISBN 978-3-89967-891-8 . ( [2] PDF file 5.5 MB)