David Clarys

Diminished episodic memory awareness in older adults: Evidence from feeling-of-knowing and recollection

The ability to reflect on and monitor memory processes is one of the most investigated metamemory functions, and one of the important ways consciousnesses interacts with memory. The feeling-of-knowing (FOK) is one task used to evaluate individuals capacity to monitor their memory. We examined this reflective function of metacognition in older adults. We explored the contribution of metacognition to episodic memory impairment, in relation to the idea that older adults show a reduction in memory awareness characteristic of episodic memory. A first experiment showed that age affects the accuracy of FOK when predictions are made on an episodic memory task but not on a semantic memory task, suggesting a particular role for episodic memory awareness in metacognitive evaluations. A second experiment showed that the age-difference in episodic FOK accuracy was removed if one took into account subjective reports of memory awareness, or recollection. We argue that the FOK deficit specific to episodic memory is based on a lack of memory awareness manifest as a recollection deficit.

The effect of aging in recollective experience: The processing speed and executive functioning hypothesis

This study was designed to investigate the effects of aging on consciousness in recognition memory, using the Remember/Know/Guess procedure (Gardiner, J. M., & Richarson-Klavehn, A. (2000). Remembering and Knowing. In E. Tulving & F. I. M. Craik (Eds.), The Oxford Handbook of Memory. Oxford University Press.). In recognition memory, older participants report fewer occasions on which recognition is accompanied by recollection of the original encoding context. Two main hypotheses were tested: the speed mediation hypothesis (Salthouse, T. A. (1996). The processing-speed theory of adult age differences in cognition. Psychological Review, 3, 403-428) and the executive-aging hypothesis (West, R. L. (1996). An application of prefrontal cortex function theory to cognitive aging. Psychological Bulletin, 120, 272-292). A group of young and a group of older adults took a recognition test in which they classified their responses according to Gardiner, J. M., & Richarson-Klavehn, A. (2000). Remembering and Knowing. In E. Tulving & F. I. M. Craik (Eds.), The Oxford Handbook of Memory. Oxford University Press. remember-know-guess paradigm. Subsequently, participants completed processing speed and executive function tests. The results showed that among the older participants, R responses decreased, but K responses did not. Moreover, a hierarchical regression analysis supported the view that the effect of age in recollection experience is determined by frontal lobe integrity and not by diminution of processing speed.

Executive Functioning and Judgment-of-Learning versus Feeling-of-Knowing in Older Adults

Feeling-of-knowing (FOK) accuracy and judgment-of-learning (JOL) accuracy were compared on separate, identical, episodic-memory tasks. The results indicated that these two measures were not correlated, suggesting that they do not tap the same metacognitive ability. We also looked at whether FOK and JOL accuracies were related differently to higher order executive functioning. In order to take advantage of within-subject variability in cognitive performance, older adults were selected as participants. They were administered the standard neuropsychological tests used to assess executive functioning. A correlational analysis clearly showed that only FOK accuracy was correlated with the executive measures, suggesting that executive control is not equally implicated in FOK and JOL.

Mediators of age-related differences in recollective experience in recognition memory

This study examined states of awareness with the Remember/Know paradigm during verbal recognition memory in young and old adults. Following the presentation of a word list, subjects undertook a recognition test and indicated whether they could consciously recollect its prior occurrence (R) or recognize it on some other basis, without conscious recollection (K). In this individual-difference approach we also incorporated various processing-speed and working-memory measures to study the link between aging, states of awareness and processing resources. The results revealed that, compared to younger adults, older adults exhibited a decline in the amount of R responses during the recognition test whereas the amount of K responses did not change. Structural equation modeling indicated that a slower processing speed associated with a limited working-memory capacity is a key to explaining age-related variance in conscious recollection. The findings offer further support for the distinction between remembering and knowing and for the processing-resources hypothesis of aging.

Ageing, remembering, and executive function.

This study was designed to investigate the relationship between executive functions and the age-related decline in episodic memory through the states-of-awareness approach. Following the presentation of a word list, a group of younger adults and a group of older adults undertook a recognition test in which they classified their responses according to the Remember-Know-Guess procedure (Gardiner & Richardson-Klavehn, 2000). In order to operationalise the executive function hypothesis, we investigated three specific executive functions (updating, shifting, and inhibition of a prepotent response) described in Miyake et al.s (2000) theoretical model, and a complex executive task. The results revealed that fewer “R” responses were made during the recognition test by the older than the younger group, whereas there was no difference between the groups in the number of “K” responses. In addition, correlations indicated that remembering depended on executive function measures, whereas knowing did not. The hierarchical regression analyses showed that controlling for executive function, and particularly for the 2-back test, largely removed the age-related variance in remembering. These findings support the notion that executive dysfunction, and specifically updating decline, plays a central role in age-related memory loss.

Aging and strategic retrieval in a cued-recall test: The role of executive functions and fluid intelligence

Cued-recall in episodic memory was investigated in relation to low and high cognitive support at retrieval, executive function level and fluid intelligence level in 81 healthy adults divided first into two age groups (young and elderly adults). The first analyses showed that age-related differences were greater when a low cognitive support was provided to recall the words. An individual index of loss of performance when the number of cues was decreased was then calculated. Hierarchical regression analysis revealed that the executive functions measure (perseverative errors on the Wisconsin Card Sorting Test) was a better candidate than the fluid intelligence measure (Cattells culture fair test) to account for the age-related variance of the size of performance loss. These findings suggest that age differences in implementing strategic retrieval may be mainly due to a decline in executive functions.

Self-reference effect and autonoetic consciousness in Alzheimer disease: evidence for a persistent affective self in dementia patients.

Episodic memory deficits are predominately the first cognitive impairment in Alzheimer disease (AD). Previous studies have demonstrated that these deficits are specifically linked to autonoetic consciousness impairment, whereas noetic consciousness remains preserved in AD. This study focused on the self-reference effect and examined emotional valence, as it has been shown that emotional content can enhance memory in AD. A task involving recognition of emotional versus neutral adjective traits after self-reference versus semantic encoding, and using the Remember/Know/Guess paradigm was administered to 22 AD patients and 18 normal controls. Results for AD patients show that self-reference increased autonoetic consciousness only for emotional and particularly negative trait adjectives. This interesting result indicates that neutral valence does not allow properties of the self to emerge in AD patients because of the progressive loss of the sense of self-linked to the disease, whereas emotional valence does.

Effects of depth-of-processing and ageing on word-stem and word-fragment implicit memory tasks: Test of the lexical-processing hypothesis

The joint effects of depth-of-processing and age on repetition priming in implicit memory tests of word-fragment completion (WFC) and word-stem completion (WSC) were investigated. The experiment consisted of three study tasks (perceptual, lexical, and semantic) and four memory conditions: implicit (WSC and WFC) and explicit (WS cued recall and WF cued recall). In the WSC condition, semantic and lexical study processing produced equal priming, both superior to the perceptual study processing, whereas the WFC test showed equal priming for these three study conditions. This finding provides clear evidence, consistent with the lexical-processing hypothesis, that depth-of-processing in WSC priming reflects a lexical rather than a semantic process. It also provides support for the view that WSC and WFC involve different processes. However, there was no evidence of an age effect on either of these two implicit tasks. The data also revealed an overall significant effect of age and depth-of-processing, and an interaction between these variables on explicit cued recall tasks, indicating that older adults benefited less than younger ones from a deep encoding condition.

Effects of attentional load and ageing on word-stem and word-fragment implicit memory tasks

The joint effects of reduced attention and age on repetition priming in implicit memory tests of word-fragment completion (WFC) and word-stem completion (WSC) were investigated. An attention load during the study phase reduced the extent of repetition priming in the WSC condition but not in WFC. This finding provides support for the view that WSC and WFC involve different processes. However, there was no evidence of an age effect on either of these two types of implicit tasks. The data also revealed an overall significant effect of age and reduced attention on explicit cued recall tasks.

PTSD psychiatric patients exhibit a deficit in remembering.

This study investigated the effects of PTSD on levels of awareness in a recognition memory task. A group of PTSD psychiatric patients and a control group without any traumatic experience were compared in remembering (R) versus knowing (K) recognition using non-trauma-related words. Results showed that overall recognition did not differ between the two groups, but in the PTSD group a significantly different pattern of Remember and Know responses was produced, indicating a shift from remembering to knowing. However, this shift from remembering to knowing in individuals with PTSD is associated with modifications in the trait anxiety level. These results are interpreted within theoretical frameworks in which R responses could be associated with distinctiveness (Rajaram, 1996) and conceptual processing (Ehlers & Clark, 2000). These collective findings would suggest the possibility that a poor general ability in the formation of source memory may eventually be a common characteristic across different types of PTSD.