Toddlers recognize multiple meanings of polysemous words

Languages often reuse words for related meanings, such as baseball cap and bottle cap, a phenomenon known as polysemy. In English, it is estimated that 40-80% of all words are polysemous, yet little is known about children's early knowledge of polysemous words. In an eye-tracking study with monolingual English-learning 2-year-olds (n=40), we found that participants recognized multiple conventional meanings for polysemous nouns. We further investigated whether toddlers succeeded at this task because they were already familiar with multiple, learned meanings for words, or whether they simply guessed the correct target based on a single or vague meaning. To test this, we also presented participants with novel, related meanings for the same English labels that are not conventional in English, e.g., the meaning “lid” for the label cap. The recognition of conventional English meanings (baseball cap, bottle cap) was significantly higher than that of the novel extension meanings (e.g., a lid) for the same label (cap). These results show that toddlers' knowledge of polysemy goes beyond a single or vague representation. At the same time, recognition of the novel extended meanings was above chance, indicating that toddlers inferred that a related meaning was the better of the two options. Word learning theories must be further developed to account for these complexities in learning.