The temporal co-occurrence of a novel word and a visual referent undoubtedly facilitates establishing the meaning of a word. It is less understood, however, how precisely learners can keep track of the frequencies of these co-occurrences across situations. Observational learning may rely on one or few highly informative exposures (propose-but-verify) or it may be driven by the collection of evidence in a more gradual and parallel manner (multiple-hypotheses tracking). We evaluated both hypotheses within two experiments and found that learners were able to keep track of more than one hypothesis for a novel word. However, this memory was strongly dependent on each learner’s individual learning path (i.e., which meanings they had considered before) and influ-enced by the order of presentation of potential referents. We argue for an account of a multiple-proposal memory rather than a multiple co-occurrence memory.