We wished to ascertain the degree of relationship between anthropoid apes and man in a field which seems to us particularly important, but on which we have as yet little information.” (Köhler, 1925, p. 1)
The work for which Wolfgang Köhler is most likely to be remembered, and for which the Primate Research Centre is a tribute, was on the mental abilities of apes.
The psychological phenomenon that most interested Köhler was insight or intelligence (“Einsicht”). Contrary to Thorndike and Pavlov who stated that learning by association (e.g., trial-and-error) was the only way animals could solve problems, Köhler believed that Chimpanzees could find solutions to problems that were “…complete whole which may, in a certain sense, be absolutely appropriate to the situation.” The work of Thorndike and Watson, which in effect showed the learning process – and animals – to be dumb, was a reaction to overly generous interpretations of the problem-solving abilities of animals by naturalists at that time. Köhler’s work was in turn a reaction to the associationists’ dumbing-down of animals and mental processes. He applied the experimental method to the questions of animal intelligence; unlike the behaviourists to follow, he provided naturalistic problems for the animals to solve.
Köhler’s most well-known work on chimp cognition was in the use of tools to gain access to food. A chimp would have to stack boxes to reach a banana that was suspended out of reach, or insert a narrow stick into a thicker one to produce a tool long enough to reach food. While Köhler’s star chimp, Sultan, did not immediately put two shorter sticks together to make one long one, he worked on the sticks for over an hour. When they had fitted together, Sultan immediately used the new tool to retrieve the bananas. This solution demonstrates insight – recognizing the “problem space” – rather than foresight.
Köhler’s work on apes was published as "Intelligenzenprüfungen an Anthropoiden" in 1917. The English version, "The Mentality of Apes" was published in 1925.