Joint action enables us to achieve our goals more efficiently than we otherwise could, and in many cases to achieve goals that we could not otherwise achieve at all. It also presents us with the challenge of determining when and to what extent we should rely on others to make their contributions. Interpersonal commitments can help with this challenge – namely by reducing uncertainty about our own and our partner’s future actions, particularly when tempting alternative options are available to one (...) or more parties. How we know whether a commitment is in place need not, however, be based on an explicit, identifiable event; in many cases, joint action is stabilized by individuals’ experience of an implicit sense of commitment, which is sensitive to subtle situational cues such as the effort costs invested by one or more agents. While an emerging body of work has investigated the conditions under which a sense of commitment may emerge and/or be strengthened, little attention has been paid to the conditions under which people are comfortable dissolving commitments. Specifically, what are the factors that modulate people’s motivation and which determine whether circumstances merit the dissolution of a commitment? After evaluating and rejecting the answers to this question suggested by standard approaches to commitment, we develop a new approach. The core insight which we articulate and defend is that, when considering whether new information or changing circumstances merit the dissolution of a commitment, people virtually bargain with their partners, performing a simulation of a bargaining process with the other person, including imagining how the other will feel and act towards them, and what effect this will have on them. The output of this simulation is a consciously accessible, affective state which provides motivation either to dissolve the commitment or to persist in it. Overall, our account expands our understanding of the phenomenology of being motivated to act committed in joint activity, an area in which existing accounts of interpersonal commitment fall short. (shrink)