A case report of compensation in daily life of a person with memory problems: detailed functional use of memory aids over a five-year period

Numerous studies have been conducted on memory aids for memory-impaired people. However, it is not known how they use these memory aids in a functional, practical way. A 20-year-old patient (MH) was monitored for five years to identify what memory aids or other means she used and how she used them to compensate for her memory problems, e.g., forgetting what was said by others in a few minutes and getting lost or turning in the wrong direction on a walk or in a building. Results indicated MH did not necessarily always use memory aids such as a notebook or calendar to compensate for her memory problems, although MH and her mother reported that she frequently used them in daily life. She coped with memory problems by using various "resources" besides the memory aid. These facts suggest that it may be necessary to redefine functionally useful compensations, which include both memory aids and resources in daily life.     

Selective memory retrieval can impair and improve retrieval of other memories

Research from the past decades has shown that retrieval of a specific memory (e.g., retrieving part of a previous vacation) typically attenuates retrieval of other memories (e.g., memories for other details of the event), causing retrieval-induced forgetting. More recently, however, it has been shown that retrieval can both attenuate and aid recall of other memories (K.-H. T. B?uml & A. Samenieh, 2010). To identify the circumstances under which retrieval aids recall, the authors examined retrieval dynamics in listwise directed forgetting, context-dependent forgetting, proactive interference, and in the absence of any induced memory impairment. They found beneficial effects of selective retrieval in listwise directed forgetting and context-dependent forgetting but detrimental effects in all the other conditions. Because context-dependent forgetting and listwise directed forgetting arguably reflect impaired context access, the results suggest that memory retrieval aids recall of memories that are subject to impaired context access but attenuates recall in the absence of such circumstances. The findings are consistent with a 2-factor account of memory retrieval and suggest the existence of 2 faces of memory retrieval.     

The spontaneous use of memory aids at different educational levels

Three groups of students in different educational levels: 8th–9th grade students (average age 15); 10th–11th grade students (average age 16); and college students (average age 21), completed a metamemory questionnaire on the use of external, general, and formal memory aids in everyday life and study situations. Short-term repetition, mental rehearsing, and summary elaboration were the most frequent aids. The least frequently used were those that require a special training to be used effectively (e.g. Digit-letters and method of loci). There were differences in the use of general memory aids due to education level, but not in the case of external and formal memory aids. Results showed also that women used memory aids more frequently than men.     

Relations between subjective evaluations of memory and objective memory performance.

Several explanations for the weak relations between subjective memory judgements and objective memory performance were investigated in two groups of normal older adults. Group 1 sampled a general population (mean age 61.6 yr., range 46-89), while Group 2 sampled subjects who were on a waiting list for memory training (mean age 63.0 yr., range 45-85 years). In both groups, subjective memory judgments were assessed with global ratings of memory capacity and with ratings of frequency of forgetting in specific memory situations. Memory performance was assessed with several well-known tests and with recently developed tests for domain-specific aspects of memory. Most tests concerned episodic memory. Study 1 also included measures of semantic, incidental and working memory. Study 2 further examined the influence of the domain-specificity of objective and subjective measures for remembering names, intentions, and texts. Relations between memory self-reports and performance were weak in both groups and for all kinds of tests. Against expectations, the low correlations could not be explained by differences between ecological and laboratory tests or incidentally and intentionally remembered information, or by differences between specific failures compared to global, stereotyped judgments. Surprisingly, correlations did not increase when subjective and objective measures assessed the same ability, like remembering names. Also noncognitive variables (mood and lifestyle) did not influence the relations. The (weak) relations between subjective and objective memory measures were comparable for subjects over and under 65 years of age. Furthermore, relations were comparable for the general population sample and the memory compliant group.     

Cross-sectional and longitudinal analyses of everyday memory lapses in older adults

Everyday memory lapses experienced by older adults (OAs) were examined using a daily-diary checklist and retrospective questionnaire. In Experiment 1, 138 younger and 138 OAs indicated the frequency of forgetting of 16 memory lapses, and whether each occurred daily during the course of a week. OAs reported more memory lapses on the questionnaire, but not the daily diary. OAs reported more frequently forgetting names and words, while younger adults had more difficulty with appointments and personal dates. Fewer memory lapses on the daily diary were related to better performance on a laboratory-memory measure for OAs. In Experiment 2, 62 OAs returned for a five-year follow-up and endorsed experiencing more memory lapses on the daily diary compared to baseline, specifically forgetting more names and words, but not the retrospective questionnaire. Daily checklist memory lapses again correlated with the laboratory-memory measure. A daily checklist may be a viable way to assess everyday memory lapses.     

Distributed learning enhances relational memory consolidation

It has long been known that distributed learning (DL) provides a mnemonic advantage over massed learning (ML). However, the underlying mechanisms that drive this robust mnemonic effect remain largely unknown. In two experiments, we show that DL across a 24 hr interval does not enhance immediate memory performance but instead slows the rate of forgetting relative to ML. Furthermore, we demonstrate that this savings in forgetting is specific to relational, but not item, memory. In the context of extant theories and knowledge of memory consolidation, these results suggest that an important mechanism underlying the mnemonic benefit of DL is enhanced memory consolidation. We speculate that synaptic strengthening mechanisms supporting long-term memory consolidation may be differentially mediated by the spacing of memory reactivation. These findings have broad implications for the scientific study of episodic memory consolidation and, more generally, for educational curriculum development and policy.     

Individual differences in everyday retrospective memory failures

The present study examined individual differences in everyday retrospective memory failures. Undergraduate students completed various cognitive ability measures in the laboratory and recorded everyday retrospective memory failures in a diary over the course of a week. The majority of memory failures were forgetting information pertaining to exams and homework, forgetting names, and forgetting login and ID information. Using latent variable techniques the results also suggested that individual differences in working memory capacity and retrospective memory were related to some but not all everyday memory failures. Furthermore, everyday memory failures predicted SAT scores and partially accounted for the relation between cognitive abilities and SAT scores. These results provide important evidence for individual differences in everyday retrospective memory failures as well as important evidence for the ecological validity of laboratory measures of working memory capacity and retrospective memory.     

The Use and Benefits of External Memory Aids in Older and Younger Adults

We examined the spontaneous use and benefits of external memory aids in older (aged 60–85 years) and younger (aged 17–31 years) adults. In Study 1, participants were or were not given the opportunity to use a memory aid in a phone message recall task. In Study 2, a memory aid was available for one of two similar tasks. Participants' spontaneous use of external memory aids was measured. On the Memory Compensation Questionnaire, older adults reported using external memory aids more frequently but were no more likely than younger adults to take notes on the messages. Older adults benefitted from the availability of notes in both studies; younger adults benefitted when the memory task was more challenging. The results illustrate the value of external memory aids and suggest that older adults may underutilize them. The findings also raise questions about the relation between self‐reported and actual use of strategies in everyday life. Copyright © 2013 John Wiley & Sons, Ltd.     

Time-dependent forgetting in visual short-term memory

ABSTRACT

Whether visual short-term memory can be lost over an unfilled delay, in line with time-dependent forgetting, is controversial and prior work has yielded mixed results. The present study explored time-dependent forgetting in visual short-term memory in relation to other factors. In three experiments, participants compared single target and probe objects over a 2 s or 10 s retention interval. The objects across trials were either similar or dissimilar (Experiment 1) and had to be remembered in the presence of an additional distractor (Experiment 2) or under conditions where the amount of time separating trials varied (Experiment 3). In all experiments, the retention interval manipulation made the biggest contribution to performance, with accuracy decreasing as the retention interval was lengthened from 2 s to 10 s. These results pose problems for interference and temporal distinctiveness models of memory but are compatible with temporal forgetting mechanisms such as decay.     

The memory of concentration camp survivors

This study is concerned with the question whether extremely emotional experiences, such as being the victim of Nazi concentration camps, leave traces in memory that cannot be extinguished. Relevant data were obtained from testimony by 78 witnesses in a case against Marinus De Rijke, who was accused of Nazi crimes in Camp Erika in The Netherlands. The testimonies were collected in the periods 1943–1947 and 1984–1987. A comparison between these two periods reveals the amount of forgetting that occurred in 40 years. Results show that camp experiences were generally well-remembered, although specific but essential details were forgotten. Among these were forgetting being maltreated, forgetting names and appearance of the torturers, and forgetting being a witness to murder. Apparently intensity of experiences is not a sufficient safeguard against forgetting. This conclusion has consequences for the forensic use of testimony by witnesses who were victims of violent crimes.     

Acute memory deficits in chemotherapy-treated adults

Data from research on amnesia and epilepsy are equivocal with regards to the dissociation, shown in animal models, between rapid and slow long-term memory consolidation. Cancer treatments have lasting disruptive effects on memory and on brain structures associated with memory, but their acute effects on synaptic consolidation are unknown. We investigated the hypothesis that cancer treatment selectively impairs slow synaptic consolidation. Cancer patients and their matched controls were administered a novel list-learning task modelled on the Rey Auditory Verbal Learning Test. Learning, forgetting, and retrieval were tested before, and one day after patients’ first chemotherapy treatment. Due to difficulties recruiting cancer patients at that sensitive time, we were only able to study 10 patients and their matched controls. Patients exhibited treatment-dependent accelerated forgetting over 24 hours compared to their own pre-treatment performance and to the performance of control participants, in agreement with our hypothesis. The number of intrusions increased after treatment, suggesting retrieval deficits. Future research with larger samples should adapt our methods to distinguish between consolidation and retrieval causes for treatment-dependent accelerated forgetting. The presence of significant accelerated forgetting in our small sample is indicative of a potentially large acute effect of chemotherapy treatment on forgetting, with potentially clinically relevant implications.     

The aftermath of memory retrieval for recycling visual working memory representations

We examined the aftermath of accessing and retrieving a subset of information stored in visual working memory (VWM)—namely, whether detection of a mismatch between memory and perception can impair the original memory of an item while triggering recognition-induced forgetting for the remaining, untested items. For this purpose, we devised a consecutive-change detection task wherein two successive testing probes were displayed after a single set of memory items. Across two experiments utilizing different memory-testing methods (whole vs. single probe), we observed a reliable pattern of poor performance in change detection for the second test when the first test had exhibited a color change. The impairment after a color change was evident even when the same memory item was repeatedly probed; this suggests that an attention-driven, salient visual change made it difficult to reinstate the previously remembered item. The second change detection, for memory items untested during the first change detection, was also found to be inaccurate, indicating that recognition-induced forgetting had occurred for the unprobed items in VWM. In a third experiment, we conducted a task that involved change detection plus continuous recall, wherein a memory recall task was presented after the change detection task. The analyses of the distributions of recall errors with a probabilistic mixture model revealed that the memory impairments from both visual changes and recognition-induced forgetting are explained better by the stochastic loss of memory items than by their degraded resolution. These results indicate that attention-driven visual change and recognition-induced forgetting jointly influence the “recycling” of VWM representations.     

Prospective memory in an air traffic control simulation: external aids that signal when to act

At work and in our personal life we often need to remember to perform intended actions at some point in the future, referred to as Prospective Memory. Individuals sometimes forget to perform intentions in safety-critical work contexts. Holding intentions can also interfere with ongoing tasks. We applied theories and methods from the experimental literature to test the effectiveness of external aids in reducing prospective memory error and costs to ongoing tasks in an air traffic control simulation. Participants were trained to accept and hand-off aircraft and to detect aircraft conflicts. For the prospective memory task, participants were required to substitute alternative actions for routine actions when accepting target aircraft. Across two experiments, external display aids were provided that presented the details of target aircraft and associated intended actions. We predicted that aids would only be effective if they provided information that was diagnostic of target occurrence, and in this study, we examined the utility of aids that directly cued participants when to allocate attention to the prospective memory task. When aids were set to flash when the prospective memory target aircraft needed to be accepted, prospective memory error and costs to ongoing tasks of aircraft acceptance and conflict detection were reduced. In contrast, aids that did not alert participants specifically when the target aircraft were present provided no advantage compared to when no aids were used. These findings have practical implications for the potential relative utility of automated external aids for occupations where individuals monitor multi-item dynamic displays.     

Updating and feature overwriting in short-term memory for timbre

Previous research has demonstrated a potent, stimulus-specific form of interference in short-term auditory memory. This effect has been interpreted in terms of interitem confusion and grouping, but the present experiments suggested that interference might be a feature-specific phenomenon. Participants compared standard and comparison tones over a 10-sec interval and were required to determine whether they differed in timbre. A single interfering distractor tone was presented either 50 msec or 8 sec after the offset of the standard (Experiment 1) or 2 sec prior to its onset (Experiment 2). The distractor varied in the number of features it shared with the standard and comparison, and this proved critical, since performance on the task was greatly impaired when the distractor either consisted of novel, unshared features (Experiment 1) or contained the distinguishing feature of the comparison tone (Experiments 1 and 2). These findings were incompatible with earlier accounts of forgetting but were fully explicable by the recent timbre memory model, which associates interference in short-term auditory memory with an "updating" process and feature overwriting. These results suggest similarities with the mechanisms that underlie forgetting in verbal short-term memory.     

Retrieval-practice task affects relationship between working memory capacity and retrieval-induced forgetting

Retrieving a subset of items from memory can cause forgetting of other items in memory, a phenomenon referred to as retrieval-induced forgetting (RIF). Individuals who exhibit greater amounts of RIF have been shown to also exhibit superior working memory capacity (WMC) and faster stop-signal reaction times (SSRTs), results which have been interpreted as suggesting that RIF reflects an inhibitory process that is mediated by the processes of executive control. Across four experiments, we sought to further elucidate this issue by manipulating the way in which participants retrieved items during retrieval practice and examining how the resulting effects of forgetting correlated with WMC (Experiments 1–3) and SSRT (Experiment 4). Significant correlations were observed when participants retrieved items from an earlier study phase (within-list retrieval practice), but not when participants generated items from semantic memory (extra-list retrieval practice). These results provide important new insight into the role of executive-control processes in RIF.     

Ontogeny of early event memory: I. Forgetting and retrieval by 2- and 3-month-olds

In 2 experiments, 2-month-olds, trained in the mobile conjugate reinforcement paradigm for two daily sessions, showed retrieval deficits relative to 3-month-olds. In Experiment 1, tests of simple forgetting administered to 2-month-olds after retention intervals of 1, 3, 6, and 9 days (a period over which 3-month-olds remember the contingency) indicated that their forgetting was complete after delays greater than 1 day. In Experiment 2, reactivation treatments administered to 2- and 3-month-olds alleviated forgetting after a retention interval of 28, but not 35, days in the 3-month-old group only. Previously, alleviated forgetting by a reactivation treatment had been demonstrated in 2-month-olds after a delay of 18 days. In both of the present experiments, performance of the two age groups did not differ during the immediate retention test at the end of training. These results suggest that neither the age of the infant nor the age of the memory determines memory retrieval after long delays; instead, it appears to be determined by the length of time that a memory has been inaccessible (i.e., forgotten). We propose that factors which delay simple forgetting will correspondingly increase the length of the interval over which a retrieval cue can still be effective in a reactivation paradigm, irrespective of the age of the infant or the age of the memory.     

Problem solving with a simple transformation problem with and without continuous external memory support

Problem solvers can use external memory aids to represent problem information. In this study, an external problem representation was either continuously available or available on demand of the participants. Two experiments explore the hypothesis that despite the higher working memory load without a continuous external memory support, problem solvers try to reduce the cognitive costs by implementing deliberate problem solving strategies. Problem solving with and without continuous external memory support was found to be largely equivalent with high and low operator implementation costs and in problem spaces of different sizes.     

Normal aging and prospective memory

We develop a laboratory paradigm for studying prospective memory and examine whether or not this type of memory is especially difficult for the elderly. In two experiments, young and old subjects were given a prospective memory test (they were asked to perform an action when a target event occurred) and three tests of retrospective memory (short-term memory, free recall, and recognition). From the perspective that aging disrupts mainly self-initiated retrieval processes, large age-related decrements in prospective memory were anticipated. However, despite showing reliable age differences on retrospective memory tests, both experiments showed no age deficits in prospective memory. Moreover, regression analyses produced no reliable relation between the prospective and retrospective memory tasks. Also, the experiments showed that external aids and unfamiliar target events benefit prospective memory performance. These results suggest some basic differences between prospective and retrospective memory.     

Directed remembering: subliminal cues alter nonconscious memory strategies

Much research on memory function has focused on changes in recognition performance brought about by differences in the processes engaged during encoding. In most of this work, participants either receive explicit instructions to remember particular items or they perform orienting (i.e., encoding) tasks that support different levels of memory performance. In daily life, however, the retention or dismissal of information often occurs without conscious intent, thereby suggesting an alternative, nonconscious route through which purposive remembering and forgetting can occur. Based on this line of reasoning, we speculated that recognition performance in a standard item-based forgetting paradigm may be moderated by subliminal cues that trigger the automatic activation of different mnemonic strategies. We report the results of two experiments that supported this prediction. In each experiment, the basic item-based forgetting effect was replicated, but via the subliminal presentation of "remember" and "forget" cues. In addition, cue-dependent differences in memory performance were traced to the operation of a covert rehearsal mechanism during encoding. We consider the implications of these findings for the non-conscious#10; operation of memory processes in everyday life.     

Retrieval-induced forgetting in implicit memory tests: The role of test awareness

Retrieval practice with particular items in memory may result in decreased recall of different, semantically related, items. This retrieval-induced forgetting effect has been demonstrated in studies using explicit memory tests. Anderson and Spellman (1995) have attributed retrieval-induced forgetting to inhibitory mechanisms. This hypothesis predicts similar effects in implicit memory tasks. In our first experiment, using Anderson and Spellman’s original paradigm, retrieval-induced forgetting was found using an explicit memory test with independent extralist retrieval cues. In our second experiment, using the same materials, retrieval-induced forgetting was also found using an implicit memory test with independent extralist retrieval cues, but only for participants who were aware of the relationship between the study and practice phase on the one hand, and the test phase of the experiment on the other. Thus, test awareness seems to mediate retrieval-induced forgetting in implicit memory tasks.