Effects of lag schedules on vocal mand variability and challenging behavior during functional communication training

Reinforcing multiple mand topographies or modalities during functional communication training (FCT) may increase the persistence of manding during challenges to treatment. However, validated procedures that reinforce the use of multiple mand topographies during FCT are lacking. Prior research demonstrated that FCT with a lag schedule of reinforcement reduced challenging behavior and increased non-vocal mand variability across modalities in individuals with autism. This finding suggests similar procedures may have similar effects on challenging behavior and vocal and/or sign manding. Also, studies have shown that lag schedules following response prompting and/or prompt fading can increase variability in vocalizations, tacts, and intraverbals. Therefore, the current study evaluated the effects of response prompting procedures and a lag schedule of reinforcement on topographical mand variability and challenging behavior during FCT. The results suggest that lag schedules can reinforce topographical mand variability during FCT following the fading or elimination of response prompts. This finding warrants study of the effects of these procedures on the resurgence of manding and challenging behavior following treatment with FCT in children with autism. Limitations of the current study and directions for future research are discussed.