Words of agency: Executed and observed vocal actions induce a temporal binding effect

Humans generally experience a sense of agency over the outcomes produced by their motor actions. This has been well established in the case of manual actions that directly affect the physical environment. Vocalizations are also actions, but they typically have only indirect effects on the environment. In the present research, we explore whether the outcomes produced by vocalizations also elicit a sense of agency. In three experiments, using an interval reproduction task, we find that performing a vocal action that produced an auditory outcome caused participants to underestimate the amount of elapsed time between actions and outcomes (i.e., temporal binding), an implicit index of the sense of agency (Experiment 1). We also show that observing others produce vocal actions elicits temporal binding, but only when the observer has direct visual access to the vocal action being executed (Experiments 2 and 3). Taken together, our findings suggest that direct observation of an action is necessary to experience a temporal binding effect for actions performed by others, and that audio-visuomotor information may play a role in the generation of temporal compression experienced over observed actions