Hooper, Saunders, McHugh, (2010)

Thought suppression appears to be a relatively ineffective and even counterproductive strategy for dealing with unwanted thoughts. However, the psychological processes responsible for unsuccessful suppression are still underspecified. One process that may be implicated is derived stimulus relations, which may underlie the formation of unintentional relations that act to hamper suppression attempts. To test this prediction, participants were trained and tested for the formation of three derived equivalence relations using a match-to-sample procedure. Subsequently, they were instructed to suppress all thoughts of a particular target word that was a member of one of the three relations and were also allowed to selectively remove words that appeared on a computer screen in front of them by pressing the space bar. Results showed, as predicted, that participants not only removed the to-be-suppressed stimulus, but also removed words in derived relations with that stimulus, thus showing transformation of suppression / interference functions via derived equivalence. The theoretical implications of this demonstration including its potential as a model for a key psychological process involved in unsuccessful thought suppression are discussed.