The age-related effect on electrophysiological correlates of successful episodic memory encoding supports the hypothesis of a deficit in self-initiated encoding processes in aging.

Episodic memory decline with aging may be due to an age-related deficit in encoding processing, older adults having increasing difficulty to self-initiate encoding strategies that support later retrieval. Using event-related potentials (ERPs), the present study explored for the first time the neural correlates of successful encoding in a resource-dependent episodic memory task, in which participants had to self-initiate processes at both encoding and retrieval. At the behavioral level, results confirm the better memory performance of young than older adults. Comparing the neural activity elicited by studied items that were and were not subsequently recalled (Subsequent Memory Effect, SME), electrophysiological data revealed that younger adults showed a significant and sustained SME, shifting from parietal to frontal areas, suggesting that they self-initiated deep encoding strategies. In older adults, the duration of brain activity was shorter and located more in the parietal than frontal areas, suggesting that they used shallow rather than deep processes. Consistent with the hypothesis of a deficit in self-initiated strategies in aging, our findings suggest that when older adults are faced with a difficult memory task (no encoding support and no cue at retrieval), they engage fewer elaborative strategies than young adults, resulting in impaired episodic memory performance.

Prospective and retrospective episodic metamemory in posttraumatic stress disorder.

OBJECTIVES: Posttraumatic stress disorder (PTSD) has been consistently associated with episodic memory deficits. To some extent, these deficits could be related to an impairment of metamemory in individuals with PTSD. This research consequently aims at investigating prospective (feeling-of-knowing, FOK) and retrospective (confidence) metamemory judgments for episodic information in PTSD. METHOD: Twenty participants with PTSD and without depression were compared to 30 healthy comparison participants on metamemory judgments during an episodic memory task. The concordance between metamemory judgments and recognition performance was then assessed by gamma correlations. RESULTS: The results confirmed that PTSD is associated with episodic memory impairment. Regarding metamemory, gamma correlations indicated that participants with PTSD failed to accurately predict their future memory performance as compared to the comparison group (mean FOK gamma correlations: .23 vs. .42, respectively). Furthermore, participants with PTSD made less accurate confidence judgments than comparison participants (mean confidence gamma correlations: .62 vs. .74, respectively). CONCLUSION: Our results demonstrate an alteration of both prospective and retrospective metamemory processes in PTSD, which could be of particular relevance to future therapeutic interventions focusing on metacognitive strategies.

Episodic feeling-of-knowing relies on noncriterial recollection and familiarity: Evidence using an online remember-know procedure.

We examined the hypothesis that feeling-of-knowing judgments rely on recollection as well as on familiarity prompted by the cue presentation. A remember-know-no memory procedure was combined with the episodic FOK procedure employing a cue-target pair memory task. The magnitude of FOK judgments and FOK accuracy were examined as a function of recollection, familiarity, or the "no memory" option. Results showed that the proportion of R and K responses was similar. FOK accuracy and magnitude of FOK judgments were higher for R and K responses than for N responses. FOK accuracy related to R and K responses were above chance level, but FOK was not accurate in the "no memory" condition. Finally, both FOK magnitude and FOK accuracy were related more to recollection than to familiarity. These results support the hypothesis that both recollection and familiarity are determinants of the FOK process, although they suggest that recollection has a stronger influence.

Age-related differences in episodic feeling-of-knowing arise from differences in memory performance.

Previous studies about the effects of ageing on the episodic feeling-of-knowing (FOK) accuracy and its underlying processes have yielded conflicting results. Recent work suggests that using alternative measures to gamma correlations might allow more accurate and informative interpretations of metamemory performance in ageing. We therefore investigated this issue with a large sample of 59 young and 61 older participants using alternative signal-detection theory (SDT) measures. These measures (receiver operating characteristic curves and Brier score) are recommended in the literature and able to reveal the characteristic profile of impairment in ageing. Our results suggest that the FOK accuracy deficit observed in the literature arises from differences in memory performance. This observation provides a convenient explanation to the previous discrepancies and furthermore supports the interest of the use of SDT-derived measures in the frame of metamemory.

Effects of aging and divided attention on episodic feeling-of-knowing accuracy.

This research investigated the effect of aging on episodic feeling-of-knowing (FOK) using a divided attention (DA) paradigm in order to examine whether DA in younger adults mimics the effects of aging when decreasing either memory encoding or monitoring processes. To that end, four groups of participants were tested on the FOK task: young adults (control group), young adults under DA at encoding, young adults under DA when making FOK judgments, and older adults. Our results showed that DA at encoding in young adults mimicked the effect of aging on memory performance, and also on FOK magnitude and accuracy, supporting the memory-constraint hypothesis (Hertzog et al., 2010). However, our results do not completely contradict the monitoring-deficit hypothesis, as DA during FOK judgments also affected FOK accuracy, but to a lesser extent than the aging effect or DA during encoding. We suggest that the age-related FOK deficit may be due to a lower level of deep encoding, leading to difficulty retrieving target-related contextual details enabling accurate prediction of subsequent recognition.

Metamemory judgments and study time allocation in young and older adults: dissociative effects of a generation task.

This study explored age-related differences in the use of metacognitive judgment to allocate extra study time according to the perceived difficulty of a learning task. The task difficulty was varied by manipulating the encoding condition which entailed either generating or reading paired associates. Perceived difficulty was measured by the global prediction rating, whereby participants predicted that they would recall fewer words in the learning task they considered hardest. Participants were first asked to predict their own future recall performance and then learned paired associates in their own time, and finally performed a cued-recall test for each encoding condition. Our results replicated earlier findings that generation improves the memory performance of both young and older adults. However, both groups thought that generation would be more difficult than reading and predicted that they would recall fewer words under that condition. The young adults allocated different amounts of study time to the two tasks, whereas the older adults allocated the same time. This was interpreted as an age-related impairment in self-initiated coordination of metacognitive judgment and the control processes required for effective allocation of study time.

Divided attention at encoding: effect on feeling-of-knowing.

This research investigated the effect of divided attention at encoding on feeling-of-knowing (FOK). Participants had to learn a 60 word-pair list under two experimental conditions, one with full attention (FA) and one with divided attention (DA). After that, they were administered episodic FOK tasks with a cued-recall phase, a FOK phase and a recognition phase. Our results showed that DA at encoding altered not only memory performance, but also FOK judgments and FOK accuracy. These findings throw some light on the central role of the quality of memory encoding to make accurate FOK judgments and provide new evidence supporting the relationship between memory and metamemory judgments.

Generation and associative encoding in young and old adults: the effect of the strength of association between cues and targets on a cued recall task.

The generation effect (i.e., better recall of the generated items than the read items) was investigated with a between-list design in young and elderly participants. The generation task difficulty was manipulated by varying the strength of association between cues and targets. Overall, strong associates were better recalled than weak associates. However, the results showed different generation effect patterns according to strength of association and age, with a greater generation effect for weak associates in younger adults only. These findings suggest that generating weak associates leads to more elaborated encoding, but that elderly adults cannot use this elaborated encoding as well as younger adults to recall the target words at test.