Recall and recognition of discourse memory across sleep and wake

The episodic context account (Gaskell et al., 2019) proposes that the act of language comprehension gives rise to an episodic discourse representation, and that this representation is prone to sleep-related memory effects. In three experiments, we tested this prediction by asking participants to read/listen to naturalistic stories before their memory was tested after a 12-hr interval, which included either daytime wakefulness or overnight sleep. To assess discourse memory, we used sentence recognition (Experiment 1; N = 386), free story recall (Experiment 2; N = 96), and cued recall (Experiments 2 and 3; N = 192). We found no evidence of sleep-related effects in sentence recognition or free recall, but cued recall (aka fill-in-the-blank) showed that the degree of time-related distortion, as indexed by both a subjective categorisation measure and Latent Semantic Analysis, was lower after sleep than after wake. Overall, our experiments suggest that the effect of sleep on discourse memory is modest but observable and may [1] be constrained by the retrieval processes (recollection vs. familiarity & associative vs. item), [2] lie on a qualitative level that is difficult to detect in an all-or-nothing scoring metric, and [3] primarily situated in the textbase level of the tripartite model of discourse processing.