An examination of facilitated acquisition and transformation of function in derived relational responding.

Abstract

Stimulus events often organize behavior in the absence of a direct learning history with that particular event. Many studies have examined indirect learning such as derived relational responding in matching-to-sample procedures and determined that the process of relating develops at approximately the same time as language (Devany, Hayes, & Nelson, 1986; Lipkins, Hayes, & Hayes, 1993). Because of this relationship with language in combination with the success of stimulus equivalence in the teaching of reading and language, it has been posited as one of the basic elements of human language and cognition (Hayes, Barnes-Holmes, & Roche, 2001). Thus, researchers have begun to examine the effects of including words and stimuli with pre-established functions, based on assumed contact with the social verbal community, into equivalence procedures. It was quickly determined that these stimuli impact the formation of equivalence classes. This seems to happen in three ways: (a) inhibition of formation, (b) rigid inflexibility of classes, and (c) facilitated acquisition. Inhibition of Class Formation. Stimuli that evoke certain emotional responses are associated with inhibition of class formation, when training that should produce classes of all meaningful stimuli is given. For example, Plaud (1995) found that the formation of snake classes was inhibited in individuals with a snake phobia, but the formation of flower classes was not. More specifically, conditional discriminations were trained that produced equivalence classes among all snake words (Cobra-Rattlers-Python) or all flower words (Yucca-Daffodil-Crocus). Fear relevant stimuli produced inhibition of equivalence responding in anxious individuals; however, non-anxious individuals were not inhibited in equivalence responding for either snake or flower class. Inhibition was also noted when equivalence training procedures were intended to create classes between sexually explicit stimuli (Plaud, Gaither, Franklin, Weller, & Barth, 1998). Both these studies examined the ability of individuals to form equivalence classes in which all stimuli had similar functions. Inhibition was noted when all the stimuli in the class had stimulus functions that evoked emotional responses (sexually explicit stimuli and snakes for snake phobics). Rigid Inflexibility of Classes. Experimental procedures designed to produce equivalence classes containing one member from two different pre-experimental equivalence classes show an inability of these classes to merge, demonstrating the inflexibility of classes of stimuli that evoke pre-experimental emotional responses. This is the counterpart of the insensitivity seen in rule-governed behavior (Matthews, Shimoff, Catania, & Sagvolden, 1977). For example, Watt, Keenan, Barnes, and Cairns (1991) trained equivalence relations between Northern Irish Catholic names, nonsense syllables, and Northern Irish Protestant symbols to individuals with either a Protestant or Catholic upbringing from either Ireland or England. Participants from Northern Ireland, where conflict between the Catholics and Protestants is ongoing, were unable to form equivalence classes including both a Protestant symbol and a Catholic name, but the English participants readily formed these classes. The authors suggest that the prior social learning of the participants interfered with the ability of individuals to form these equivalence relations. Leslie, Tierney, Robinson, Keenan, Watt, and Barnes (1993) tested the effects of pairing threatening situations, nonsense syllables, and pleasant state adjectives in a MTS procedure in anxious and non-anxious adults. All non-anxious participants formed equivalence classes that included one stimulus from each set; however, the anxious individuals did not form equivalence classes given the same amount of training. The authors attributed this difference to previously established behavioral relations interfering with the emergence of equivalence relations in the laboratory. …