Sense of Object Ownership Changes With Sense of Agency

Personal objects are known to have several psychological effects on their owners. However, the formation of a sense of object ownership (SoOO) remains unclear. This study tested the hypothesis that a sense of agency (SoA) is related to the formation of SoOO. As such, we conducted nine experiments: participants played a simple game on a computer, where they controlled colored balls using a mouse. We manipulated the SoA for the balls by altering the delay or consistency between the participants' actions and the ball movements; the participants felt a strong SoA when they controlled the ball without delay or when the ball moved correspondingly to their mouse movements. After the game, participants evaluated the extent to which they felt that the ball was their object. The results consistently showed that the SoOO for the ball was stronger when the SoA was higher than when it was lower. Moreover, this modulation occurred independently of the preference for balls, and the SoOO was higher when the action stemmed from one's own will rather than from another's. Our findings suggest that intended action plays an important role in forming SoOO.