Learning new words by reading books: Does semantic information help?

Encountering new words during reading is a common experience of any adult reader and it constitutes an important source of word knowledge. Despite the ubiquity of this phenomenon, studies remain scarce in adults. Here, we addressed new word acquisition in adults using a natural contextual exposure, and we focused on the influence of context informativeness on orthographic learning. Indeed, previous studies suggest that the availability of semantic information plays an important role in orthographic learning in adults, but no such advantage was found in children. We hypothesised that this discrepancy comes from the fact that new word learning was examined almost only through artificial settings in adults. On the contrary, in the present study, adult participants were exposed to new words by reading a book. Half of the new words were embedded in informative contexts (easy to infer new word meaning) and the other half in less informative contexts. Both recall and recognition tasks were used to assess orthographic and semantic learning. The results showed efficient learning of the orthographic form and no reliable effect of the context informativeness. Regarding semantic learning, we found that if a word was correctly spelled, its definition was more likely to be retrieved. This shows that the orthographic and semantic dimensions of a word co-occurring in context are likely to influence each other during lexical acquisition. More generally, the present experiment showed that using an ecological learning design is essential to understand the mechanism of new word learning.