The age prospective memory paradox within the same sample in time-based and event-based tasks

The present research investigated the age prospective memory (PM) paradox by testing the performance of the same participants on laboratory and naturalistic PM tasks. Younger, middle-aged, and older adults performed three tasks (time-based, event-based with focal cue, and event-based with nonfocal cue); first in the laboratory, then in the context of their everyday lives. Additionally, the social importance of PM tasks was manipulated in the laboratory. As expected, age-dependent declines on the laboratory tasks were reversed in the naturalistic tasks. Middle-aged adults performed as well as younger adults in the laboratory and as well as the elderly outside of the laboratory. When the social importance of laboratory tasks was stressed, the performance of younger adults fell. In addition, older adults showed higher self-reported commitment to the naturalistic tasks than both younger and middle-aged adults. Findings are discussed in the context of possible explanations for the age PM paradox.     

Age, Focal Processing, and Monitoring in Event-Based Prospective Memory

While there is some consensus that prospective memory (PM) declines with age, the reasons for differences in performance across age groups are not fully understood. This experiment examines two factors that are likely to affect the magnitude of observed age group differences: type of PM task and whether participants monitor the task environment for the opportunity to complete the PM task. Younger and older adults were engaged in an ongoing test of short-term memory and were asked to perform one of two different event-based PM tasks. Younger adults performed better than older adults on both focal and nonfocal PM tasks. In addition, younger adults were able to perform both types of tasks equally well, but older adults were more successful on the focal task than on the nonfocal task. Age group differences in self-reported PM monitoring were also evident and were related to performance. These findings and their implications for current theoretical conceptions of PM aging are discussed.     

Prospective memory and ageing paradox with event-based tasks: A study of young,young-old,and old-old participants

Research on ageing and prospective memory—remembering to do something in the future—has resulted in paradoxical findings, whereby older adults are often impaired in the laboratory but perform significantly better than younger adults in naturalistic settings. Nevertheless, there are very few studies that have examined prospective memory both in and outside the laboratory using the same sample of young and old participants. Moreover, most naturalistic studies have used time-based tasks, and it is unclear whether the prospective memory and ageing paradox extends to event-based tasks. In this study, 72 young (18–30 years), 79 young-old (61–70 years), and 72 old-old (71–80 years) participants completed several event-based tasks in and outside the laboratory. Results showed that the ageing paradox does exist for event-based tasks but manifests itself differently from that in time-based tasks. Thus, younger adults outperformed old-old participants in two laboratory event-based tasks, but there were no age effects for a naturalistic task completed at home (remembering to write the date and time in the upper left corner of a questionnaire). The young and old-old also did not differ in remembering to retrieve a wristwatch from a pocket at the end of the laboratory session. This indicates that the paradox may be due to differences in ongoing task demands in the lab and everyday life, rather than the location per se. The findings call for a concentrated effort towards a theory of cognitive ageing that identifies the variables that do, or do not, account for this paradox.     

Prospective and retrospective memory in normal aging and dementia: an experimental study

Two experiments investigated the effects of normal aging and dementia on laboratory-based prospective memory (PM) tasks. Participants viewed a film for a later recognition memory task. In Experiment 1, they were also required either to say "animal" when an animal appeared in the film (event-based PM task) or to stop a clock every 3 min (time-based PM task). In both tasks, young participants were more successful than older participants, who were, in turn, more successful than patients with Alzheimer's disease (AD). For successful remembering in the time-based task, older participants and AD patients checked the clock more often than did young participants. In Experiment 2, participants were asked to reset a clock either when an animal appeared in the film (unrelated cue-action) or when a clock appeared in the film (related cue-action). Responses were faster in the related condition than in the unrelated condition. Again, there were differences in PM performance between young and older participants, and between older participants and AD patients. The observed deficits were not due to the forgetting of the PM task instructions in either experiment. Retrospective memory (RM) tasks (digit span, sentence span, free recall, and recognition) were more impaired by AD than were the PM tasks. Factor analysis revealed separate factors corresponding to RM and PM.     

Prospective memory and frontal lobe function

The study sought to examine the role of frontal lobe functioning in focal prospective memory (PM) performance and its relation to PM deficit in older adults. PM and working memory (WM) differences were studied in younger aged (n = 21), older aged (n = 20), and frontal injury (n = 14) groups. An event-based focal PM task was employed and three measures of WM were administered. The younger aged group differed from the other two groups in showing significantly higher scores on PM and on one of the WM measures, but there were no differences at a statistically significant level between the older aged group and the frontal injury groups on any of the memory measures. There were, however, some differences in correlations with a WM measure between groups. It is concluded that there are similarities and differences in the deficits in PM between older adults and patients with frontal lobe injury on focal as well as nonfocal PM tasks.     

A Developmental Investigation of Prospective Memory: Effects of Interruption

The effects of interrupting an event-based prospective memory (PM) task and its associated ongoing task were compared for two groups of children: 8- to 9-year-olds (n?=?35) and 12- to 13-year-olds (n?=?28). Additionally, PM performance was examined as a function of attainment on a battery of tests of executive functioning (viz., Controlled Oral Word Association Test, Letter Number Sequencing Test, Stroop Color and Word Test, and Trail Making Test). A significant main effect of age indicated that the older children correctly carried out intended actions more often than the younger children. Consistent with the prefrontal model of PM, interruption had no impact on PM accuracy in the older group but produced reliable decrements to the accuracy of the younger group. Whereas IQ showed no association with PM performance, reliable relations between PM skills and aspects of their executive functioning were found.     

The Importance of On-going Concurrent Activities as a Function of Age in Time- and Event-based Prospective Memory

Time-based prospective memory is assumed to involve more self-initiated activities than event-based prospective memory. As age negatively affects self-initiated activities, older participants will show more prospectivememory deterioration than younger participants in time-based tasks. Einstein, McDaniel, Richardson, Guynn, and Cunfer (1995) indeed observed such a decrement in time-based prospective memory while d'Ydewalle, Utsi, and Brunfaut (1996) obtained a better time-based than event-based prospective memory among elderly. The on-going concurrent activity in Einstein et al. (1995) involved answering general questions, whereas d'Ydewalle et al. (1996) used a face-identification task. In an attempt to explain the discrepant results, the present experiment compares time- and event-based memory with young and older participants using the two types of on-going task. However, the better performance of the older participants in the timebased prospective memory task is obtained in the two on-going tasks. A difference in timing constraints in the procedure may explain why the older participants in Einstein et al. (1995) did perform more poorly in the timebased task, whereas our ageing participants did not show such a deterioration, suggesting that the slowing down of mental activities may provide a better explanation than the increasing lack of self-initiated activities by the elderly. All age effects in prospective-memory performance disappear when performance on the target items (i.e. items where a prospective-memory response is required) in the on-going task is taken into account. We emphasise the need to study trade-offs in prospective-memory research as a prospective-memory task is always embedded in another (on-going) activity.     

Comparing older and younger adults in an event-based prospective memory paradigm containing an output monitoring component

Two experiments with younger and older adults were conducted to investigate the output-monitoring component of event-based prospective memory. In the standard form of the task, participants must remember to press a key when a certain class of items is encountered. To evaluate output monitoring, event-based cues were repeated and participants were asked to press a different key if they could remember that an earlier response was made to a particular cue. Younger adults forgot fewer of their successful responses, but displayed a distinct bias to claim that they had responded earlier when actually they had forgotten to respond. By contrast, older adults displayed this bias much less frequently. Elaborated responding to cues had the effect of improving the performance of younger, but not older adults. The results are discussed in terms of natural repetitions and omission errors that might be made in everyday prospective memory tasks.     

Comparing Older and Younger Adults in an Event-Based Prospective Memory Paradigm Containing an Output Monitoring Component

ABSTRACT

Two experiments with younger and older adults were conducted to investigate the output-monitoring component of event-based prospective memory. In the standard form of the task, participants must remember to press a key when a certain class of items is encountered. To evaluate output monitoring, event-based cues were repeated and participants were asked to press a different key if they could remember that an earlier response was made to a particular cue. Younger adults forgot fewer of their successful responses, but displayed a distinct bias to claim that they had responded earlier when actually they had forgotten to respond. By contrast, older adults displayed this bias much less frequently. Elaborated responding to cues had the effect of improving the performance of younger, but not older adults. The results are discussed in terms of natural repetitions and omission errors that might be made in everyday prospective memory tasks.     

Age-Related Changes in Neural Activation During Working Memory Performance

Changes in frontal lobe functions are a typical part of aging of the brain. There are age-related declines in working memory performance, a skill requiring frontal lobe activation. This study examined neural activation, using [15 O] water positron emission tomography (PET) methodology, during performance on two verbal working memory tasks in younger and older participants. The results demonstrated the typical areas of activation associated with working memory performance (e.g., dorsolateral prefrontal cortex and inferior parietal cortex) in both groups. However, the younger participants utilized the right dorsolateral prefrontal cortex and anterior cingulate gyrus significantly more than the older participants. In turn, the older participants used the left dorsolateral prefrontal cortex significantly more than the younger participants and maintained material-specific lateralization in their pattern of activation. These findings are consistent with a previous report of different age-related patterns of frontal activation during working memory.     

Prospective memory performance across adolescence

In the present study, the authors explored age differences in event-based prospective memory (PM) across adolescence. The tasks consisted of an ongoing task (OT; i.e., personality questionnaire items, math problems) and an embedded prospective task that required participants to remember to make a special response whenever they encountered a PM cue (i.e., a negative word in the OT). The 341 participants (aged 13-22 years) revealed a significant main effect of age, which indicated better PM performance of young adults compared with teenagers. Moreover, when emphasizing the OT versus the PM task, teenagers' PM profited from PM emphasis more than did young adults' PM. The authors discuss the data in the context of limited executive capacity as a factor influencing cognitive development across adolescence.     

Time-based and event-based prospective memory across adulthood: underlying mechanisms and differential costs on the ongoing task

The authors investigated the phenomenon that performance in an ongoing task declines when individuals must carry out a prospective memory (PM) task. This effect is referred to as the PM interference effect. The authors examined whether the PM interference effect differs between event-based and time-based PM tasks and whether it is increased among the elderly. The authors also investigated adult age differences in PM performance and the potential underlying mechanisms of the age deficits in PM. They found that the PM interference effect was greater in event-based than in time-based tasks. However, aging was not associated with an increase in PM interference effects. Age differences in PM performance were more exaggerated in time-based than event-based PM, but they were not mediated by age differences in traditional cognitive ability measures. In time-based PM, age showed a unique adverse effect even after controlling for the ability to externally monitor the time, leading to the possibility that aging disrupts time-based PM because of deficits in internally processing the time.     

Positive effects of subclinical depression in prospective memory and ongoing tasks in young and old adults

Results reported in the literature show that depression can have either negative or neutral effects on prospective memory (PM). The goal of the present study was to broaden the analysis of depression-related effects on PM, with regard to the possibility that subclinical depression may have positive influence on PM. A total of 120 participants from four groups (young/old, subclinically depressed/non-depressed) completed event- and time-based PM tasks embedded in the linear orders task or stories task, respectively. In the event-based PM task no effects of depression were found, whereas depressed participants were more accurate in the time-based PM task, where higher monitoring during the last minute of the task was observed. It was also found that depressed participants built a mental model in the linear orders task more accurately than controls. Results of the present study are discussed with reference to the analytical rumination hypothesis.     

Age‐related differences in everyday prospective memory tasks: The role of planning and personal importance

The aim of the present studies was to investigate whether age‐related improvement found in naturalistic but experimenter‐given prospective memory (PM) tasks can be generalized to real‐life intentions. In Study 1, younger, middle‐aged, and older adults generated a list of intended activities for the following week; one week later they marked the tasks that they had performed. The participants were also asked to rate the importance of each listed intention and to describe the circumstances of completion that were already known to them. We found that, compared with younger adults, older adults attributed a higher degree of importance to their intentions and had the circumstances of their completion better planned. However, the age‐related benefit in the PM performance for all listed intentions was not present for the very important and well‐planned tasks. In Study 2 we manipulated whether younger adults engaged or not in the detailed planning of when their intentions could be completed. It was demonstrated that younger adults who had to perform detailed planning completed their intended activities more often than those who did not plan for their intentions. The results support explanations of the age‐related benefit in everyday PM that highlight the role of importance and planning.     

Working memory in event‐ and time‐based prospective memory tasks: Effects of secondary demand and age

An experiment is reported examining the role of working memory in two laboratory‐based prospective memory (PM) tasks. Participants viewed a film for a later recognition memory task while simultaneously monitoring auditorially presented arithmetic problems for incorrect solutions. The arithmetic verification task was either low demand or high demand. In addition, participants were required either to indicate whenever an animal appeared in the film (event‐based PM task), or whenever 3 min had elapsed (time‐based PM task). PM performance was higher when the arithmetic task was low demand than when it was high demand. Young participants were more successful in both PM tasks than older participants, but only under high demand. Age did not interact with PM task type overall, and the young participants were faster overall in both types of PM task. Taken together, the results indicate that working memory plays an important role in PM tasks.     

Whoops, I did it again: commission errors in prospective memory

Prospective memory research almost exclusively examines remembering to execute an intention, but the ability to forget completed intentions may be similarly important. We had younger and older adults perform a prospective memory task (press Q when you see corn or dancer) and then told them that the intention was completed. Participants later performed a lexical-decision task (Phase 2) in which the prospective memory cues reappeared. Initial prospective memory performance was similar between age groups, but older adults were more likely than younger adults to press Q during Phase 2 (i.e., commission errors). This study provides the first experimental demonstration of event-based prospective memory commission errors after all prospective memory tasks are finished and identifies multiple factors that increase risk for commission errors.     

Aging and Individual Variation in Interhemispheric Collaboration and Hemispheric Asymmetry

ABSTRACT

Thirty younger (Mean Age = 19.9 years) and 20 older adults (Mean Age = 74.7 years) performed Physical and Name Identity letter-matching tasks (matches were either within or between hemispheres) to study age-related changes in 1) the efficiency with which the two hemispheres interact with each other and 2) hemispheric asymmetry. In order to determine whether age-related effects were associated with differences in cognitive resources, the same individuals completed a set of memory span tasks. Performance on the letter-matching tasks indicated that the costs of interhemispheric collaboration were greater for older than for younger participants. However, within the older group, the advantage of spreading processing across both hemispheres increased as memory span decreased, suggesting that older individuals who are challenged by cognitive complexity are more likely to show increased benefits from between-hemisphere processing than individuals who are not so challenged. There was also an overall left visual field/right hemisphere advantage for the younger but not for the older group, suggesting greater age-related declines in right- than left-hemisphere function.     

The Duration and Intensity of the Exposure Light as Factors in Determining the Course of the Subsequent Dark-Adaptation: I. the Matching Method

The authors investigated the phenomenon that performance in an ongoing task declines when individuals must carry out a prospective memory (PM) task. This effect is referred to as the PM interference effect. The authors examined whether the PM interference effect differs between event-based and time-based PM tasks and whether it is increased among the elderly. The authors also investigated adult age differences in PM performance and the potential underlying mechanisms of the age deficits in PM. They found that the PM interference effect was greater in event-based than in time-based tasks. However, aging was not associated with an increase in PM interference effects. Age differences in PM performance were more exaggerated in time-based than event-based PM, but they were not mediated by age differences in traditional cognitive ability measures. In time-based PM, age showed a unique adverse effect even after controlling for the ability to externally monitor the time, leading to the possibility that aging disrupts time-based PM because of deficits in internally processing the time.     

Relationship of cognitive strategy use to prospective memory performance in a diverse sample of nondemented older adults with varying degrees of cognitive complaints and impairment

Although older adults typically have better performance on prospective memory (PM) tasks carried out in naturalistic settings, a paucity of research directly assesses older adults’ use of compensatory strategies on such tasks. The current study investigates external memory strategy use during performance of a clinical PM test that features both short-term (in laboratory) and long-term (out of laboratory) subtasks (i.e., the Royal Prince Alfred Prospective Memory Test – RPA-ProMem. Nondemented, community-dwelling older adults (n = 214; mean age = 80.5; 68.2% female; 39.7% non-white) with mild cognitive impairment, subjective cognitive decline, and healthy controls completed the RPA-ProMem while external strategy use was permitted and recorded. Overall, participants utilized external strategies 41% of the time on the RPA-ProMem. Increased utilization of external memory strategies was significantly associated with better PM performance. Additionally, better performance on executive functioning tasks was associated with increased use of external memory strategies. Results are discussed in relation to how memory strategy use can be enhanced to improve everyday memory ability in older adults at risk for dementia.     

Younger and older adults’ prospective memory: the role of delay task difficulty

ABSTRACT

There is mixed evidence on the impact of delay task difficulty on prospective memory (PM) performance and little research has examined this among older adults. The present study examined younger (N = 60) and older (N = 57) adults’ prospective memory (PM) performance after completing an easy or difficult Raven’s matrices task. To assess whether delay difficulty impacted how often participants thought about their PM intention, participants were asked to report on what they thought about during the delay task itself and retrospectively after all tasks were completed. Younger adults outperformed older adults on the PM task; however, delay task difficulty had no impact PM for either age group. Reports of thinking about the intention during the delay task differed by age group depending whether they were online or retrospective, however, overall greater reports of thinking about the intention was positively associated with PM performance.