Abstract
This manuscript is part of a special issue to commemorate professor Paul Eelen, who passed away on August 21, 2016. Paul was a clinically oriented scientist, for whom learning principles (Pavlovian or operant) were more than salivary responses and lever presses. His expertise in learning psychology and his enthusiasm to translate this knowledge to clinical practice inspired many inside and outside academia. Several of his original writings were in the Dutch language. Instead of editing a special issue with contributions of colleagues and friends, we decided to translate a selection of his manuscripts to English to allow wide access to his original insights and opinions. Even though the manuscripts were written more than two decades ago, their content is surprisingly contemporary. This manuscript is a transcription of a lecture that was published in 1980. It was Paul Eelen's first public presentation after a two-year study in the United States, which has inspired much of his later thinking. The text can be viewed as a manifesto for behaviour therapy as it was then advancing in Belgium and the Netherlands. This presentation was given as the introduction to the L.A.P.P. seminar day held October 27, 1980, which was themed: Behaviour modification. The lecture was published as: Eelen, P. (1980). Gedragstherapie en gedragsmodificatie: Achtergronden. Leuvens Bulletin L. A. P. P., 39, 1-19.