Lila Gleitman’s body of work on word learning raises an apparent paradox. Whereas work on syntactic bootstrapping depends on learners retaining information about the set of distributional contexts that a word occurs in, work on identifying a word’s referent suggests that learners do not retain information about the set of extralinguistic contexts that a word occurs in. I argue that this asymmetry derives from the architecture of the language faculty. Learners expect words with similar meanings to have similar distributions, and so learning depends on a memory for syntactic environments. The referential context in which a word is used is less constrained and hence contributes less to the memories that drive word learning.