“…A few studies (Dymond & Barnes, 1998;Green, Sigurdardottir, & Saun-ders, 1991;Sigurdardottir, Green, & Saunders, 1990) reported that participants respond appropriately to conditional discriminations throughout an MTS task just as well when not instructed. Ribes-Inesta and Martinez-Sanchez (1990) and Martinez and Tamayo (2005) demonstrated that providing inaccurate instructions can disrupt performance on MTS tasks. A number of studies have shown that instructions can make participants relatively insensitive to changes in the contingencies within a study (Galizio, 1979;Hayes, Brownstein, Haas, & Greenway, 1986;Shimoff, Catania, & Matthews, 1981;Shimoff, Matthews, & Catania 1986), but none of these involved MTS preparations.…”