Lexical integration of novel words learned through natural reading.

Lexical competition between newly acquired and already established representations of written words is considered a marker of word integration into the mental lexicon. To date, studies about the emergence of lexical competition involved mostly artificial training procedures based on overexposure and explicit instructions for memorization. Yet, in real life, novel word encounters occur mostly without explicit learning intent, through reading texts with words appearing rarely. This study examined the lexical integration of words learned through text reading. In Experiment 1, two groups of participants read a short book with embedded novel words. Only one group was asked to memorize the unfamiliar words. In the semantic categorization task, we found evidence for lexical competition with slower responses to existing orthographic neighbors (e.g., hublot) of the newly learned words (e.g., hubbot) than to a set of matched items. This effect was found independently of the group 24 h after initial exposure. In addition, a facilitation pattern was observed immediately after the reading session. However, post hoc analyses suggested that the competition effect was mainly driven by the data from the group receiving explicit learning instructions. Experiment 2 aimed to replicate the findings obtained in the group without explicit learning instructions. The results revealed the same pattern, characterized by a facilitatory effect immediately after the reading session and an inhibitory effect 24 h after the exposure. Overall, these results showed that lexical competition emerged from a naturalistic reading after a delay, regardless of whether participants were asked to learn novel words or not.