Raz Leib
Technische Universität München
Hearing a crash while parking a car often comes with the feeling of fear about the amount of damage caused. However, if no damage is observed, we often wonder whether we were responsible for the crashing sound. In this case, our sense of agency, that is, the belief that we are responsible for any movements and changes in our body and environment, can change to the belief that someone else is responsible for the crashing sounds.
Forming the sense of agency is believed to follow a Bayesian integration framework. During interaction with the environment, humans consider prior beliefs regarding the acting agent and integrate this information with the likelihood that they are responsible for the observed outcome. While this framework can explain some aspects of self-agency, it does not consider different factors that can affect agency judgment. For example, when humans collaborate with others on a task where a reward is given based on a team effort and not individual performance, they tend to attribute successful outcomes to their acts and contributions, while less successful outcomes are attributed to other acting agents. In such a case, the Bayesian integration framework needs to be modified.
To explore how success or failure affects the integration between prior belief and observations, we designed a collaborative reaching task between a human player and a virtual player. In this task, both players simultaneously performed a blind reaching movement to a target displayed on a screen and stopped as close as possible to the center of the target. After returning to their start positions, one of the landing positions was displayed, that is, either the landing position of the human player or the virtual player. We rewarded the players with points based on the distance between the displayed landing position and the target’s center. Following this reward display, we asked the participants whether they believed the displayed position resulted from their own or their virtual partner’s movement. We found that in cases of both human player movement and virtual player movement, high points rewards triggered participants to claim ownership of the displayed movement. When the movement was inaccurate and less rewarding, participants tended to attribute the movement to the virtual player. These results suggest that despite having similar prior beliefs and sensory observations when comparing movements, the reward factor can also affect the sense of agency. We propose that this factor should be integrated into the idea of Bayesian inference as the basis for the sense of agency.
DFG SPP "The Active Self" 