Hemispheric processing of memory is affected by sleep

When does sleep affect veridical and false memory consolidation? A meta-analysis

It is widely accepted that sleep aids in the encoding, consolidation, and retrieval processes involved in memory processing; however, the conditions under which sleep influences memory may be substantially constrained. In a meta-analysis, we examined the effects that sleep has on both veridical (accurate) and false memory consolidation, in studies using the Deese/Roediger-McDermott (DRM) paradigm for memory of thematically related words. The meta-analysis revealed that, whereas there was no overall effect of sleep on either accurate or false memories, the effect of sleep on overall memories was moderated by two constraints. First, sleep effects were influenced by the number of words within each themed word list, relating to differences in processing of the associative network of related words. Second, sleep effects were greater in recall than in recognition tests. Thus, whether sleep consolidation increased or decreased DRM veridical or false memory effects depended on the specific features of the memory task.

Increased phantom recollection after sleep

Sleep is known to benefit memory consolidation, but its effect on false memory is less clear. We applied the simplified conjoint recognition paradigm to investigate how sleep affects the cognitive processes behind correct or false recognition, according to fuzzy-trace theory, and measured the retrieval of verbatim traces, retrieval of gist traces, and phantom recollection. Participants studied 24 lists of semantically related words lacking the strongest common associate or theme word. Recognition was tested 12 h later, following either a night's sleep or daytime wakefulness. The recognition test featured studied words, nonstudied theme words (false recognition), and unrelated words. False recognition rate was higher after sleep than after daytime wakefulness. True recognition rate was the same. Analysis of the cognitive processes underlying recognition showed that phantom recollection was higher after sleep. Assuming that phantom recollection reflects the retrieval of strong gist traces, sleep may strengthen gist traces and promote gist extraction.

Sleep and mindfulness meditation as they relate to false memory

By a systematic analysis of the current literature, we compare two states of sleep and meditation in terms of their role in the formation or suppression of Deese-Roediger-McDermott (DRM) false memory. We aim to suggest that the occurrence of false memory under these two states is a result of reinforcing some abilities and changes in cognitive systems which can ultimately improve some aspects of cognitive functions. In our analogy, we propose that: (1) both sleep and meditation may improve source monitoring ability whose failure is one of the most important mechanisms in producing false memories, and (2) despite improvement in source monitoring ability, adaptive cognitive processes, as mechanisms which are common in sleep and meditation, can still produce false memories. In conclusion, we propose that in spite of their contribution to false memory through adaptive processes, the beneficial role of sleep and meditation in cognition may be more prominent than their harmful role.