Individuals shift their language to converge with interlocutors. Recent work has suggested that convergence can target not only observed but also expected linguistic behavior, cued by social information. However, it remains uncertain how expectations and observed behavior interact, particularly when they contradict each other. We investigated this using a cooperative map task experiment, in which pairs of participants communicated online by typing messages to each other in a miniature “alien” language that exhibited variation between alien species. The overall task comprised (...) three phases, in each of which participants were told that they would be paired with a different partner. One member of the pair was given explicit linguistic expectations in each phase, while the software controlled whether or not observed behavior from their partner would be consistent or inconsistent with these expectations. The other participant was given no such expectations, allowing us to control for the role of expectation. Participants converged to both observed and expected linguistic behavior, and convergence was boosted when observation and expectation were aligned. When expected and observed behavior were misaligned, participants updated their expectations, though convergence levels did not drop. Furthermore, participants generalized what they learned about one partner to apparent novel partners of the same alien species. We also discuss individual variation in convergence patterns and the lack of a relationship between linguistic convergence and success at the map task. Findings are consistent with observations outside the laboratory that language users converge toward expected linguistic behavior. They also have broader implications for understanding linguistic accommodation and the influence of social information on linguistic processing and production. (shrink)