The predictability of a partner's actions modulates the sense of joint agency.

When people coordinate their actions with others, they experience a sense of joint agency, i.e., shared control over actions and their consequences. The current study examined whether the predictability of others' actions modulates joint agency. Each participant coordinated with two confederate partners to produce tone sequences that matched a metronome pace. The timing of the confederates' actions was manipulated so that one partner's actions were highly predictable in time and the other's less predictable. After each sequence, participants rated their experience of joint agency on a scale from shared to independent control. People felt more shared control when they coordinated with the more predictable partner, even after controlling for their own performance accuracy and variability. Thus, people rely on predictions of others' actions to derive a sense of joint agency during interpersonal coordination.