People use roles to quickly predict how others will act, what they know, and when they can be replaced

Everyday life requires that we navigate dozens of interactions with strangers quickly and effectively. Here we hypothesized that representations of roles (e.g., cashier, mechanic, doctor) enable people to build rapid expectations about what others will do, what they know, and who else serves the same function. To test this, we used a self-paced reading paradigm in which we timed how long it took participants to read short passages about social interactions. Across three studies (N=300 participants per study), we show that role representations support real-time expectations about how other people might act (Study 1), the knowledge they might possess (Study 2), and whether it is appropriate to generalize across agents (Study 3). Moreover, people reported more surprise when the events deviated from role expectations and were more likely to misreport what happened in a way that conformed to role expectations. Our results suggest that roles are a powerful route for social understanding that has been previously understudied in social cognition. Using a self-paced reading paradigm, we show that, from just the mention of a role, people build rapid expectations about how other people will act, what they know, and whether they can be interchangeable with others in the same role.