Involvement of episodic memory in language comprehension: Naturalistic comprehension pushes unrelated words closer in semantic space for at least 12 h

Recent experience with a word significantly influences its subsequent interpretation. For instance, encountering bank in a river-related context biases future interpretations toward ‘side of a river’ (vs. ‘financial bank’). To explain this effect, the episodic context account posits that episodic memory helps bind word meanings in the language input, creating a temporary, context-specific representation that can bias subsequent lexical interpretation. This account predicts that even unrelated words would be linked together in episodic memory, potentially altering their interpretation. In Experiments 1–3, participants read unrelated word pairs (e.g., sword—microwave, privacy—export) embedded in meaningful sentences, then completed a speeded relatedness judgement task after delays of 5 min, 20 min, or 12 h (including sleep). Results showed that sentence exposure increased the likelihood of the unrelated pairs being judged as related—a robust effect observed across all delay intervals. Experiment 4 showed that this exposure effect was abolished when words in a target pair were read in separate sentences, suggesting that the exposure effect may be dependent on lexical co-occurrence. Experiment 5, also with a 12-h delay (including sleep), additionally used an innovative word arrangement task to assess word relatedness without presenting the target pairs simultaneously or successively. In line with relatedness judgement, sentence exposure pushed the unrelated words closer in semantic space. Overall, our findings suggest that a context-specific representation, supported by episodic memory, is generated during language comprehension, and in turn, these representations can influence lexical interpretation for at least 12 h and across different linguistic circumstances. We argue that these representations endow the mental lexicon with the efficiency to deal with word burstiness and the dynamic nature of language.