Emergent Intraverbal and Reverse Intraverbal Behavior Following Listener Training in Children with Autism Spectrum Disorder

The present study replicated and extended Smith et al. (2016) by examining whether intraverbal responding to “when” questions emerged following listener training in children with ASD. Results showed that intraverbal responses emerged over baseline levels across all three sets of questions following listener training for five of six participants, but only one participant showed correct performances on all nine intraverbals after listener training. The remaining participants required additional listener training for one (and in one case two) stimulus sets before the intraverbals emerged at perfect (100%) levels. Participant 6 differed from the other five participants in that he required intraverbal training for set 1 before the intraverbals emerged for that set. Subsequently, emergence of intraverbal responding occurred following listener training for sets 2 and 3.

Emergent intraverbal responding can be traced directly back to the history of reinforcement in listener training (Horne & Lowe, 1996; Palmer, 2016). Results from the present study show that listener responding facilitated the emergence of intraverbal behavior but is does not show empirically how this transfer came about. Conceptually, joint control (Lowenkron, 2006) may be useful in describing how this transfer occurred. Because participants were able to tact all stimuli involved in the listener training, it is possible that the listener training evoked both a listener response and a tact. The tact behavior may have occurred covertly or overtly. For example, perhaps touching the picture denoting toothpaste evoked the tact, “Toothpaste.” If so, the touching behavior and the tact were both reinforced in the presence of the verbal antecedent stimulus (/What do you use when you brush your teeth?/). The response, “toothpaste” which began as tact may subsequently have been evoked as a self-echoic behavior. This self-echoic behavior may then have functioned as a mediating response, facilitating transfer across verbal operants (Lowenkron, 2006). The model of joint control is especially useful for understanding complex and delayed discriminations such as the one observed in the present study. This interpretation is compatible with data from participant 6, who initially required a visual prompt together with the antecedent verbal stimulus to learn the intraverbal responses. Unfortunately, data were not collected on correct or incorrect tacts that occurred during listener training, but such data would have been useful, have been reported in previous studies (e.g., Kodak & Paden, 2015), and should be considered in future studies. On the other hand, covert tacts, if they occurred, would not have been detected by such data.

We also examined whether the emergent intraverbal responses would reverse (e.g., answering the question, /When do you go to bed?/ with the vocal response, “at night” after having learned to say, “go to bed” when hearing /What do you do at night?/). Results showed that reverse intraverbal responses emerged across all three stimulus sets for three of the participants. For the remaining three participants, responding was more variable, but reverse intraverbals occurred above baseline levels for most stimulus sets. A variable that was constant across listener training and intraverbal probes was the verbal antecedents, which was identical across both conditions and included responding to when questions. This may have facilitated the transfer from listener behavior to intraverbal behavior. The antecedent for the reverse intraverbals, however, included responding to either who or what questions. Hence, the antecedent for the emergent intraverbal responses differed from the antecedent for the reverse intraverbals, and this could explain, in part, why there was more emergence of intraverbals as compared to reverse intraverbals.

To our knowledge, this is the first demonstration of reverse intraverbal responding emerging from listener training in individuals with ASD. However, the purpose of the study was not to show or to propose that listener training is the most effective way of establishing emergent intraverbal responding. Indeed, studies have shown that tact training typically is more effective in establishing intraverbal responding than listener training both in typically developing individuals as well as in individuals with ASD (e.g., Allan et al., 2015; Cortez et al., 2020; Petursdottir et al., 2008a, b; Thakore & Petursdottir, 2021). Rather, we sought to examine whether intraverbal and reverse intraverbal relations could emerge after listener training to demonstrate how behavior analysts may account for verbal behavior emerging without a direct reinforcement history.

The results of this study showed emergence of intraverbal responses as well as many instances of reverse intraverbal responding, suggesting that the intraverbal responding was not rote learning, but based on the reinforcement history in listener training. In rote learning, the intraverbal responses can be said to be under configural stimulus control (Devine et al., 2016; Pearce, 1987, 2002), in which the intraverbal response is controlled by the whole of the verbal antecedent stimulus. Under configural stimulus control, there is no independent control by the individual elements of the verbal antecedent. In the present study, because reverse intraverbals emerged, these relations could not have been established under configural stimulus control, suggesting that listener training may perhaps prevent establishing intraverbal responses under configural stimulus control. This possibility merits further research.

Also related to stimulus control, 100% correct responding occurred from the onset of listener training for participants 1 and 5. Because no errors were made and no prompts were given during listener training for these two participants, they had the listener behavior in their repertoire before entering the study. Yet, they did not respond correctly to the intraverbal probes until they were required to respond to the antecedents for the intraverbal response as a listener.

The results for participant 6 showed that listener training was not sufficient to establish intraverbal responding for set 1. Training the intraverbals using a visual stimulus as a prompt was required before the intraverbal responses occurred. The intraverbal training was identical to the intraverbal probes except that a visual prompt was presented together with the antecedent verbal stimulus. For example, if the verbal antecedent stimulus was, /When does Santa come? /, a picture denoting Christmas was shown to the participant. Hence, no echoic prompts were provided at any time during any phase of the experiment. After learning the intraverbals in set 1, intraverbal responding emerged following listener training for the two subsequent stimulus sets. This finding may suggest that intraverbal training using visual prompts may be an effective way to establish intraverbal responding when listener training alone is not sufficient. This could be explored in future studies.

The reasons why listener training was not sufficient to establish intraverbal responding for participants 6 is not clear. It is possible that the participant lacked certain key prerequisite skills, although the absence of specific prerequisites was not detected from data in the present study. Future research could examine more closely whether it is possible to identify prerequisite verbal behavior using assessments such as the Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP, Sundberg, 2008) in addition to the ABLLS-R (Partington, 2010). Also, an analysis of the extent to which the participants show other potential prerequisites such being able to acquire verbal behavior through naming and joint control could be explored.

Questions also remain about sources of stimulus control established during listener training and intraverbal probes. One limitation of the current study is that we did not conduct an analysis of the stimulus control exerted by individual elements of the antecedent verbal stimulus. Future research could examine the effects of variations of the same verbal antecedent on emergence (e.g., /when do you go to bed?/ vs. /when do you go to sleep/” on the intraverbal response, “at night”).

Further, an analysis of the effects of the visual stimulus used during listener training on intraverbal emergence was not conducted as only one picture for each question was used. It may be the case that only one part of each picture (e.g., the moon included in the picture for the response, “at night”) exerted stimulus control over the response and future research could examine the effects of using a larger array of pictures during listener training to see if this facilitates emergence of the intraverbal response.

For participants 1 and 5, variation in the criterion to conduct additional probes or stop conducting these occurred. For these two participants, extra post-listener training probes and reverse intraverbal probes were conducted. Variations in decisions to continue versus stop probes is a limitation which should be corrected in future studies.

Another limitation pertains to experimental control. Performance on the reverse intraverbals trials were assessed only once during baseline. Additional baseline probes for reverse intraverbals would have provided a more convincing demonstration of experimental control, and hence, a clearer demonstration of the emergence of revers intraverbals.

留言 (0)

沒有登入
gif