What do we know when we claim to know nothing? Partial knowledge of word meanings may be ontological, but not hierarchical

Two studies investigated whether knowledge about ontological category membership exists early in the word learning process—specifically, when words are partially known—and if so, how such knowledge is represented. Participants made decisions about the ontological category membership of words at three levels of knowledge: words they correctly defined (known), words recognized as familiar (frontier), and words mistakenly identified as nonwords (unknown). Accuracy on this task improved as a function of word level. Participants were able to identify the broad ontological categories to which words at all three levels of knowledge belonged, as well as the more specific ontological categories to which the words belonged. Overall, results indicated that knowledge about ontological category membership is available for words at very low levels of knowledge, and that this knowledge does not necessarily follow the strict hierarchical organization some ontological systems are thought to embody (e.g. Keil 1979). Implications for the acquisition and representation of word meanings are discussed.