Interfering with inner speech during action encoding impacts their execution

Most of the studies so far overlooked the role of inner speech in action, especially new actions. We conducted a behavioral experiment asking participants to observe videos to acquire two actions. In the experimental group, participants performed an articulatory suppression task, continuously repeating a syllable, so as to interfere with the inner speech. In the control group, participants were requested to continuously tap their middle finger on the table. We hypothesized that, interfering with inner speech, participants could not provide themselves with instructions about how to perform the actions, consequently impacting their ability to acquire them. The results confirmed the hypotheses. Compared to the Dual-task Control Group, the Articulatory Suppression Group is overall more impaired in action acquisition and, in part, in motor performance quality. These results confirm the role of inner speech in cognition, providing new evidence about its function in action learning and execution.