Incidental learning of new meanings for familiar words

Adults often learn new meanings for words they already know, for example due to language evolving with changes in technology (e.g., the newer internet-related meaning of “troll”). Learning new word meanings generally takes place incidentally, such as when reading for comprehension. The experiments in this thesis explore some of the different factors that impact adults’ acquisition and long-term retention of novel meanings for familiar words learned incidentally from reading stories. Experiment 1 assessed the effect of number of exposures on incidental learning. The results showed reasonably good memory of new word meanings after only two exposures, and a linear, incremental increase in recall with more exposures. There was also no forgetting after one week, regardless of the number of exposures during training. Experiment 2 compared incidental to intentional learning, showing that new meanings for familiar words are harder to learn under incidental conditions, but may be less susceptible to forgetting. Experiments 3-4 explored whether a testing effect may have contributed to the good long-term retention of new word meanings in the previous experiments, and whether the method of immediate test affects this. These experiments showed that memory tests (cued recall or meaning-to-word matching) considerably enhanced retention of new word meanings. Experiments 5-6 explored whether sleep is important for active consolidation of new word meanings, as previously shown for learning new word forms. In these experiments sleep improved explicit knowledge of new meanings when it occurred in the immediate interval between learning and test. No evidence of active consolidation was found; the results are consistent with a passive benefit of sleep in protecting against interference. Together these experiments demonstrate that adult readers are proficient at learning new meanings for familiar words from a small number of encounters within naturalistic story contexts, and certain factors can have an important impact on learning.