Testing two mechanisms by which rational and irrational beliefs may affectthe functionality of inferences

This article describes a role playing experiment that examined the sufficie ncy hypothesis of Rational Emotive Behaviour Therapy (REBT). This propositi on states that it is sufficient for rational and irrational beliefs to refe r to preferences and musts, respectively, if those beliefs are co affect th e functionality of inferences (FI). Consistent with the REBT literature (e. g. Dryden, 1994; Dryden & Ellis, 1988; Palmer, Dryden, Ellis & Yapp, 1995) results from this experiment showed chat rational and irrational beliefs, a s defined by REBT, do affect FI. Specifically, results showed that people w ho hold a rational belief form inferences chat are significantly more funct ional chan chose chat are formed by people who hold an irrational belief. C ontrary to REBT theory, the sufficiency hypothesis was not supported. Thus, results indicated that it is not sufficient for rational and irrational be liefs to refer to preferences and musts, respectively, if those beliefs are to affect the FI. It appears, then, chat preferences and musts are not suf ficient mechanisms by which rational and irrational beliefs, respectively, affect the FI. Psychotherapeutic implications of these findings are conside red.