Effects of a speaker immersion procedure on the production of verbal operants.

Abstract

Introduction Children with native intellectual disabilities and children from impoverished backgrounds frequently lack or do not develop functional verbal repertoires naturally (Hart and Risley, 1995). Even when children with delays in language development receive behavioral language interventions, their prior lack of a history of reinforcement for vocal verbal communication calls for intensive language learning instruction (Greer, Chavez-Brown, Nirgudkar, Stolfi, & Rivera-Valdes, 2005; Greer & Keohane, 2005; Pistoljevic, 2008; Pistoljevic & Greer, 2006). These children need intensive language experiences to compensate for deficits in their learning history and to advance their verbal development. According to Woods (1984), when the verbal antecedents from the parents were absent, children with native disabilities were usually silent, lacking speech, whereas typically developing children were more likely to initiate interactions without verbal antecedents from others. Many students with native or environmental disabilities acquire correct vocal verbal behavior during instruction but may not emit it spontaneously in non-instructional settings (NIS) (Greer, 2002; Nuzzolo-Gomez & Greer, 2004). they lack is or spontaneous speaker behavior, including verbal operants emitted without any verbal antecedent and used in ways that were not previously reinforced (Ross, Nuzzolo, Stolfi & Natarelli, 2006). This behavior is a major goal of language training programs. Williams and Greer (1993) compared the effects of linguistic and verbal behavior curricula on the acquisition of functional speech. For the linguistic curriculum, the students responded to the verbal behavior of the instructor (e.g., What is that?) by emitting intraverbal responses. In the verbal behavior curriculum, the student responses were under the control of non-verbal stimuli (i.e., the presence of the nonverbal stimuli served as an antecedent). Operant procedures were used for both methods and both produced the same number of correct responses. Overall, the verbal behavior curriculum resulted not only in the students' learning more words but also in the maintenance and generalization of verbal operants. In other words, the two curricula produced two very different repertoires, and only the verbal behavior curriculum resulted in spontaneous speech under the control of non-verbal environmental stimuli. Typically developing children seem to learn to communicate in effortless ways. They are more likely to respond to nonverbal antecedents in order to initiate verbal interactions spontaneously, readily responding to the natural establishing operations (EOs) that control human communicative behavior (e.g., lack of social attention when attention is preferred for pure tacts; deprivation or aversive conditions for mands). Therefore, one possible reason why children with disabilities are often observed not emit pure tacts and mands in NIS is that they were taught to produce these verbal operants only under the partial antecedent verbal control of others. That is, tacts and mands were taught as intraverbals and the relevant direct control of nonverbal antecedents was never actually learned. In other words, these children learned to talk only when asked for a response (e.g., What do you want?) and not in response to a natural EO (e.g., deprivation or aversive conditions). As an alternative, one could avoid verbal antecedents and arrange the environment to create EOs that would encourage the emission of pure mands (i.e., requests for desired items independent of verbal antecedents) (Pistoljevic, 2008). Within the verbal behavior model, speaker behavior is represented by six basic operants or functions, each defined by effects on the listener. Included are echoics, mands, tacts, intraverbals, textual responses and autoclitics (Skinner, 1957; Ross et al., 2006). Among these operants, tacts and mands are of particular interest for the current study. …