Professional magicians regularly use pantomimed grasps (i.e., movements towards imagined objects) to deceive audiences. To do so, they learn to shape their hands similarly for real and pantomimed grasps. Here we tested whether this form of motor expertise provides them a significant benefit when processing pantomimed grasps. To this aim, in a one-interval discrimination design, we asked 17 professional magicians and 17 naïve controls to watch video clips of reach-to-grasp movements recorded from naïve participants and judge whether the observed movement was real or pantomimed. All video clips were edited to spatially occlude the grasped object (either present or imagined). Data were analysed within a drift diffusion model approach. Fitting different models showed that, whereas magicians and naïve performed similarly when observing real grasps, magicians had a specific advantage compared with naïve at discriminating pantomimed grasps. These findings suggest that motor expertise may be crucial for detecting relevant cues from hand movement during the discrimination of pantomimed grasps. Results are discussed in terms of motor recalibration.

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. Vocalisations are also actions, but they typically have only indirect effects on the environment. In the present research, we explore whether the outcomes produced by vocalisations 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 Public Significance StatementWhen we perceive that an action causes an outcome, we tend to underestimate how much time elapsed between cause and effect. This phenomenon, known as 'temporal binding' has been shown in a range of situations where physical actions (e.g., flipping a light switch) produce an outcome (e.g., a light coming on). For the first time, this research shows that a similar phenomenon occurs when something we say (rather than do) causes the outcome, and therefore provides new insights into how beliefs about causality affect the perception of time. These findings also contribute to our understanding of how agency is experienced over outcomes