This paper argues that a class of popular views of collective intention, which I call “quasi-psychologism”, faces a problem explaining common intuitions about collective action. Views in this class hold that collective intentions are realized in or constituted by individual, mental, participatory intentions. I argue that this metaphysical commitment entails persistence conditions that are in tension with a purported obligation to notify co-actors before leaving a collective action attested to by participants in experimental research about the interpersonal normativity of collective (...) action. I then explore the possibilities open to quasi-psychologists for responding to this research. (shrink)