A persistent mystery in language acquisition is how speakers are able to learn seemingly arbitrary distributional restrictions. This article investigates one such case: the fact that speakers resist using certain adjectives prenominally (e.g. ??the asleep man). Experiment 1 indicates that speakers tentatively generalize or CATEGORIZE the distributional restriction beyond their previous experience. Experiment 2 demonstrates that speakers are sensitive to STATISTICAL PREEMPTION–that is, speakers learn not to use a formulation if an alternative formulation with the same function is consistently witnessed. Moreover, they are able to generalize the restriction to apply to other members of the category as well. Finally, experiment 3 finds evidence that speakers DISCOUNT a pseudo-preemptive context, rationally ignoring it as uninformative.