Waking rest during retention facilitates memory consolidation, but so does social media use

A short period of post-encoding waking rest has been shown to benefit subsequent memory performance. For example, past research suggests that waking rest after learning Icelandic-German word pairs boosts subsequent recall relative to an equally long period of social media use. Such findings are typically interpreted as evidence in favor of diversion retroactive interference. According to this account, non-specific cognitive processing inhibits consolidation and thus impairs storage of information encoded previously. However, the effect might alternatively be explained by similarity retroactive interference according to which retrieval is hampered by information processed during retention. Here, we report two experiments that shed light on the mechanisms underlying the waking rest effect. In both experiments, participants either wakefully rested, used social media, or engaged in additional Norwegian-German vocabulary learning after the original learning phase. We performed multinomial processing tree (MPT) analyses to disentangle latent storage and retrieval contributions to cued recall and recognition performance. We did not find any memory differences between the waking rest and social media conditions in either experiment. Moreover, storage, but not retrieval, was reliably impaired in the vocabulary condition. Thereby, the present research provides direct behavioral evidence for a dominant role of consolidation in the waking rest effect.