Contributions of Tactile Information to the Sense of Agency and Its Metacognitive Representations

Despite the ubiquitous presence of tactile information in our daily activities, studies of how we experience agency of our actions have rarely relied on manipulated visuo-tactile feedback. Instead, what is often manipulated are the distal (and arbitrarily associated) consequences of our actions. The few studies that did investigate whether tactile information contributes to the experience of agency have been limited to the binary assessment of tactile feedback about the outcome of an action being present or absent. Here, we went beyond the coarse comparison of agency with versus without tactile feedback and introduced instead an experimental manipulation where we could control the amount of mismatch between predictions and observations. Participants (N = 40) reached with their right hand toward a ridged plate with a specific orientation and saw online feedback that could match or differ from their action in one of three ways: the physical plate's orientation, the action's timing, or the hand's position in space. Absolute subjective ratings revealed that an increased mismatch in tactile information led to a diminished sense of agency, similar to what has been reported for spatial and temporal mismatches. Further, estimations of metacognitive efficiency revealed similar Mratios in identifying visuo-tactile violation predictions as compared to visuo-temporal violations (but lower than visuospatial). These findings emphasize the importance of tactile information in shaping our experience of acting voluntarily and show how this important component can be experimentally probed.