Acquisition of Incidental Bidirectional Naming: Isolating the Effects of Probing and Mixed-Operant Instruction.

The primary purpose of the present experiment was to explore the extent to which repeated probing contributes to the establishment of incidental bidirectional naming (Inc-BiN). Whenever repetitive probes alone did not suffice to establish Inc-BiN, we investigated whether mixed-operant instuction (MOI)--the rapid rotation of operants within each of a series of trial blocks--improved Inc-BiN. Nine children with autism or language delays aged 3-6 participated. Three of nine participants were exposed to an extended-baseline condition, while the remaining six were exposed to one of two brief-baseline conditions before MOI. We used a multiple probe design across three novel stimulus sets, to isolate the effects of repeated probing. During post-MOI Inc-BiN probes, all participants across conditions demonstrated the emergence of Inc-BiN. Repetitive probes sufficed to establish Inc-BiN in two of three participants who were assigned to the extended-baseline condition, while for the third, Inc-BiN improved after MOI. In addition, we examined the extent to which the probe sequence impacted Inc-BiN skills. Three participants, P1, P2, and P3, were exposed to speaker (tacts) probes first, while the remaining six were exposed to listener probes first. During generative Inc-BiN probes, when testing speaker responses before listener responses (P1-P3), only listener responses emerged for two of them. In contrast, when testing listener before speaker responses, both repertoires were observed for three (P4, P5, and P7) of six participants. A one-month follow-up Inc-BiN probe demonstrated maintenance of listener responses for seven of eight participants, and tacts were maintained for three of them.