In his obituary, Aloys Fischer wrote that, “undoubtedly Külpe was the second founder of experimental psychology on German soil; for with every change of base he made it a requirement that an experimental laboratory should be provided.”[1] Külpe studied as a doctoral student and assistant to Wundt at the University of Leipzig, though his ideas differed from Wundt as he developed his own research (Boring, 1961).
Külpe made significant contributions to the field of psychology, some of which are still relevant, including the systematic experimental introspection, imageless thoughts, mental sets, and abstraction.
He lived a large portion of his life with his older, unmarried cousins, Ottillie and Marie Külpe, at their residences in Leipzig, Würzburg, Bonn, and Munich.
[2] In between 1882 and 1883, Külpe studied at the University of Berlin, where he attended the lectures of Heinrich von Treitschke, a nationalist German historian.
Following his studies in Berlin, he transferred to Göttingen, where he spent two years as a student of Georg Elias Müller, where it is said he received the idea for his doctoral dissertation.
He was able to increase the size and improve the equipment until the Würzburg laboratory became the most outstanding institute of psychology in Germany aside from Leipzig.
Here, he trained numerous influential psychologists including the likes of Max Wertheimer, Kaspar Ach, and Henry Watt.
[2] In his later years, Külpe began to focus less on psychological issues and more on his interests in philosophical problems such as esthetics, where it seemed his true passion lay.
It was said that had he lived longer, Külpe likely would have accepted the request to succeed Friederich Jodl and establish a psychological laboratory at the University of Vienna as well.
In doing so, they developed and improved the process of what became known as systematic experimental introspection, which was the retrospective reporting of the experiences of a subject after performing a complex task involving thinking, remembering, or judging.
The work focused on the idea of imageless thought, which is the belief that there is an objective significance that can be found within experiences that are not necessarily associated with specific words, symbols or signs.
[4] Külpe anticipated the notion of imageless thought in his early work as evidenced in Grundriss der Psychologie.
Influenced by his interest in philosophy, Külpe believed that there were certain sensations, feelings, or presentations that could neither be described nor associated in the mind with an image.
Once they were given the opportunity to objectively self-observe and describe what was neither sensation, feeling, nor presentation, yet was still a thought process Külpe and his colleagues identified the need for new definitions and concepts aside from those that already exist.
[3] In one famous experiment Külpe instructed participants to observe a display of numbers, letters, colors, and shapes.
For example, if he told the participants beforehand to report on the numbers observed, then they were unable to describe the letters, colors, or shapes with any accuracy after the experiment.
[2] Külpe wrote in a letter about the conclusions from these experiments: "The old doctrine of an inner sense with the involved idea of a distinction between the reality of consciousness and objectivity must now have its opportune renewal in the domain of psychology.
[2] Since he varied the Aufgabe (task) slightly in each session of the experiment, he was able to find a correlation between the range of attention and degree of consciousness.
For example, in situations where participants were asked to provide a superordinate category, or superior group within a classification system, for birds, they were more likely to respond by saying, ‘Animal’ than a specific bird such as a ‘hummingbird.’ As a result, Külpe and the students at the Würzburg laboratory concluded that behavior such as the above example could not be explained according to associationistic logic.
Eventually the mental set was seen as a factor that could account for a large portion of the variation in the ways that people solve problems.
[4] Oswald Külpe's books and published works cover a variety of subject matter, which impacted his interest in psychology.
[6] Two years later, Grundriss der Psychologie was translated into English by Edward Titchener under the title Outlines of Psychology.
[14] The book is less than 350 pages and went through seven editions and four translations, including into English by W. B. Pillsbury and Titchener under the title Introduction to Philosophy.
Once they were given the opportunity to objectively self-observe and describe what was neither sensation, feeling, nor presentation, yet was still a thought process; Külpe and his colleagues identified the need for new definitions and concepts aside from those that already exist.
[15] As Külpe wrote: “The subjects began to speak in the language of life and assign less importance to the presentations for their inner world.
They knew and thought, they judged and understood, they grasped the meaning and saw connections without receiving any real help from occasionally occurring imagery.”[15] Die Realisierung, a three-volume text composed of Külpe's lectures, was published from 1912 through 1923.