Wakeful Rest Benefits Recall, but Not Recognition, of Incidentally Encoded Memory Stimuli in Younger and Older Adults

Abstract

Older adults exhibit deficits in episodic memory tasks, which have often been attributed to encoding or retrieval deficits, with little attention to consolidation mechanisms. More recently, researchers have attempted to measure consolidation in the context of a behavioral experiment using the wakeful rest paradigm (i.e., a brief, quiet period of minimal stimulation, which facilitates memory performance, compared to a distractor task). Critically, older adults might not produce this effect, given established age differences in other episodic memory processes and mind-wandering. In three experiments, we directly compared younger and older adults in modified versions of the wakeful rest paradigm. Critically, we utilized incidental encoding procedures (all experiments) and abstract shape stimuli (in Experiment 3) to limit the possibility of retrieval practice or maintenance rehearsal as potential confounding mechanisms in producing the wakeful rest effect. Wakeful rest reliably and equally benefited recall of incidentally encoded words in both younger and older adults. In contrast, wakeful rest had no benefit for standard accuracy measures of recognition performance in verbal stimuli, although there was an effect in response latencies for non-verbal stimuli. Overall, these results suggest that the benefits of wakeful rest on episodic retrieval are preserved across age groups, and hence support age-independence in potential consolidation mechanisms as measured by wakeful rest. Further, these benefits do not appear to be dependent on the intentionality of encoding or variations in distractor task types. Finally, the lack of wakeful rest benefits on recognition performance might be driven by theoretical constraints on the effect or methodological limitations of recognition memory testing in the current paradigm.

An online experiment that presents challenges for translating rest-related gains in visual detail memory from the laboratory to naturalistic settings

“…Participants engaged sufficiently with the demands of the spot-the-difference game as demonstrated by the number of trials responded to and proportion of correct responses, which resonates with laboratory findings where interference effects have been observed when using the same or similar perceptual task as the current study [ 16 , 17 , 19 – 21 , 23 , 25 , 49 , 55 , 57 ]. We do however acknowledge that some findings are mixed [e.g., 56 , 62 , 63 ]. Furthermore, demonstrable engagement with the requirements of the spot-the-difference task does not necessarily indicate that a participant maintained a fully engaged state (of sustained attention and sensory processing) that was detrimental to consolidation.…”

“…Despite extensive evidence demonstrating that quiet rest is beneficial to memory; the exact mechanisms underpinning this effect remain poorly characterised. Several potential mechanisms have been proposed, including sustained attention and task engagement [ 23 , 25 ], a reduction in sensory processing [ 20 , 21 ] and rich autobiographical thinking activities [ 49 , 65 ] that would otherwise interfere, as well as more intentional mnemonic strategies including active rehearsal [ 63 ]. However, the exact factor, or, more probable, combination of factors, that underpin the rest effect remain poorly understood.…”

Impaired episodic verbal memory recall after 1 week and elevated forgetting in children after mild traumatic brain injury – results from a short-term longitudinal study

“…Our results indicate that ALF could be related to a consolidation impairment in children after mTBI although encoding and retrieval could still have influenced outcome. Additionally, recent evidence from a study in healthy adults suggests that wakeful rest, a methodologically accepted approach to promote and study consolidation, had a positive effect on recall performance, but not on recognition ( Millar and Balota, 2022 ), possibly implying that consolidation processes may have different effects on recall and recognition performance. Thus, future studies are needed to investigate the role of encoding as well as the complex interplay between acquisition, storage and retrieval on delayed memory performance, to investigate the processes underlying ALF ( Wagner et al, 2005 ; Shimamura, 2011 ; Levy, 2012 ).…”

Novel Approaches to Memory and Aging: The Editorial

“…These outcomes suggest that in designing and implementing prevention and promotion protocols, researchers need to consider motivational factors, such as curiosity, and focus on the presentation of positive and negative information in competition instead of limiting attention to isolated positive and/or negative manipulations. Additionally, incidental memory seems to benefit from wakeful rest (i.e., a brief period of about 10 min of minimal stimulation while individuals are awake) across age groups, supporting its potential suitability in older adults’ consolidation mechanisms [ 7 ].…”