The Effects of Blocking and Joint Control Training on Sequencing Visual Stimuli.

We assessed the effects of blocking on the accuracy of arranging visual stimuli in sequences as an attempt to assess whether verbal behavior mediates nonverbal performance. Across three experiments, college students were trained to echo and tact the names of abstract images vocally (Experiments 1 and 3) and with hand signs (Experiment 2), and then, they were tested to see whether they could sequence these pictures accurately in the presence of their dictated names or signs. When participants were required to engage in a vocal blocking task, sequencing performances learned via either vocal or hand signs deteriorated (Experiments 1 and 2). In Experiment 3, vocal blocking deteriorated sequencing learned vocally, but not when participants were responding to visual samples (i.e., visual matching). Overall, only 2 out of 12 participants required joint control training to accurately sequence stimuli. Combined results suggest that vocal blocking may serve to prevent verbal behavior that could be mediating sequencing, and that joint control training is not necessary for adults to perform the sequencing task.