The role of inner speech in task switching: A dual-task investigation

This dual-task study examined the role of inner speech in task switching. Experiment 1 demonstrated that disrupting inner speech via articulatory suppression dramatically increases switch costs. The three subsequent experiments attempted to specify the role of inner speech in task switching by introducing additional manipulations (i.e., types of cues in Experiment 2, task difficulty in Experiment 3, and the number of tasks switched between in Experiment 4) and then examining whether these factors modulated the magnitude of the articulatory suppression effect on switch costs. Only the cue type manipulation––hypothesized to affect the degree to which participants rely on verbal self-instruction––modulated the articulatory suppression effect, suggesting that inner speech serves as an internal self-cuing device by retrieving and activating a phonological representation of the upcoming task.