Word learning in the context of semantic prior knowledge: evidence of interference from feature-based neighbours in children and adults

The presence of phonological neighbours facilitates word-form learning, suggesting that prior phonological knowledge supports vocabulary acquisition. We tested whether prior semantic knowledge similarly benefits word learning by teaching 7-to-10-year-old children (Experiment 1) and adults (Experiment 2) pseudowords assigned to novel concepts with low or high semantic neighbourhood density according to feature norms. Form recall, definition recall, and semantic categorisation tasks were administered immediately after training, the next day, and one week later. Across sessions, pseudowords assigned to low-density (versus high-density) semantic neighbourhood concepts elicited better word-form recall (for adults) and better meaning recall (for children). Exploratory cross-experiment analyses demonstrated that the neighbourhood influence was most robust for recalling meanings. Children showed greater gains in form recall than adults across the week, regardless of links to semantic knowledge. While the results suggest that close semantic neighbours interfere with word learning, we consider alternative semantic dimensions that may be beneficial.