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.     

Is time-based prospective remembering mediated by self-initiated rehearsals? Role of incidental cues, ongoing activity, age, and motivation

The present research examined self-reported rehearsal processes in naturalistic time-based prospective memory tasks (Study 1 and 2) and compared them with the processes in event-based tasks (Study 3). Participants had to remember to phone the experimenter either at a prearranged time (a time-based task) or after receiving a certain text message (an event-based task) and record the details of occasions when they thought about this intention during a 7-day delay interval. The rehearsal and retrieval of time-based tasks was mediated by more automatic than deliberate self-initiated processes. Moreover, the number of reported rehearsals without any apparent triggers was reliably higher in time- than in event-based tasks. Additional findings concern the effects of age, motivation, and ongoing activities on rehearsal and prospective memory performance.     

Predictors of time-based prospective memory in children

This study identified age differences in time-based prospective memory performance in school-aged children and explored possible cognitive correlates of age-related performance. A total of 56 7- to 12-year-olds performed a prospective memory task in which prospective memory accuracy, ongoing task performance, and time monitoring were assessed. Additional tests of time estimation, working memory, task switching, and planning were performed. Results showed a robust relationship between age and prospective memory performance even after controlling for ongoing task performance. Developmental differences in time monitoring were also observed, with older children generally adopting a more strategic monitoring strategy than younger children. The majority of age-related variance in prospective memory task performance could be explained by cognitive resources, in particular planning and task switching. In contrast, no further independent contribution of time estimation was observed. Findings are in line with the development of strategic behavior, as well as executive functioning, in school-aged children.     

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.     

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.     

情绪刺激对前瞻记忆的影响

使用情绪图片作为背景任务刺激,通过两个实验来考察积极情绪和消极情绪对时间性和事件性前瞻记忆的影响。结果发现,对于背景任务的反应时,在时间性前瞻记忆和事件性前瞻记忆中,情绪的主效应都显著。而对于前瞻任务的正确率,在两种前瞻记忆中,情绪的主效应都不显著。将两个实验的数据合并分析发现,对于前瞻任务的正确率,任务类型的主效应显著,即时间性前瞻记忆的成绩显著高于事件性前瞻记忆; 而情绪的主效应不显著。结果表明,背景任务中不同的情绪刺激会对个体完成背景任务的速度产生影响,而对前瞻记忆任务的执行不会产生影响。     

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.     

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.     

Psychosocial stress enhances time-based prospective memory in healthy young men

Forgetting of intentions (such as to take one's medication) is the most frequent everyday memory failure. No study so far has looked into the possible consequences stress might exert on memory for intentions (i.e., prospective memory). Twenty healthy young male adults were exposed to a psychosocial stress test and a non-stress condition. After a delay of 15 min, a time- and an event-based prospective memory task were administered during the peak of cortisol concentrations. Results show that participants performed significantly better in the time-based memory task after stress in comparison to the non-stress condition. In contrast, there was no stress effect on event-based prospective memory. The results demonstrate that prospective memory might be enhanced when participants are exposed to stress prior to the memory task and that this effect is associated to stress-related glucocorticoid effects.     

Time monitoring and executive functioning in children and adults

This study examined time-based prospective memory performance in relation to individual and developmental differences in executive functioning. School-age children and young adults completed six experimental tasks that tapped three basic components of executive functioning: inhibition, updating, and mental shifting. Monitoring performance was examined in a time-based prospective memory task in which participants indicated the passing of time every 5min while watching a movie. Separate analyses of the executive functioning data yielded a two-factor solution for both age groups, with the updating and inhibition tasks constituting a common factor and the shifting tasks constituting a separate factor. Both children and adults showed accelerating monitoring functions with low rates of clock checking during the early phase of each 5-min interval. However, compared with adults, children needed more clock checks for obtaining the same level of response accuracy. Executive functioning had selective effects on time-based prospective memory performance. In both children and adults, monitoring performance was related to the inhibition and updating components, but not to the shifting component, of executive functioning. We conclude that difficulties in temporary maintenance and updating of working memory contents may create discontinuities in sense of time, leading to an increased reliance on external cues for time keeping.     

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.     

Time-based prospective remembering: Interference and facilitation in a dual task

The aim of this study was to analyse prospective memory behaviour when people have to fulfil two different intentions whose retention intervals partially overlapped. More specifically, the purpose of the study was to explore the effects of a secondary PM task (either time-based or event-based) on performance of a main time-based PM task. Four embedded conditions were tested: two event-based ones and two time-based ones. The time- and event-based interpolated tasks differed in how closely their target time was to the 20-minute response required by the main time-based task (16th and 19th min., respectively). The results indicated that when a main time-based prospective memory task shares a portion of the retention interval with a second time-based prospective task, this overlapping facilitated performance on the main task. However, the interpolated tasks appeared to be affected by the moment in which they were administered during the execution of the main time-based task. More specifically, a decrease in the interpolated task performance was observed when this was time-based and had to be executed very closely to the target time of the main task. On the contrary, when the two tasks were different (event-based vs. time-based), there was neither interference, nor facilitation.     

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.     

Strategic sequence planning and prospective memory impairments in frontally lesioned head trauma patients performing activities of daily living

The aim of this research was to study strategic sequence planning and prospective memory in activities of daily living (ADL) in 10 patients with frontal lobe lesions after a mild to moderate closed head injury (CHI). The lesions were documented radiologically. The CHI patients were compared to 12 normal controls with a neuropsychological test battery and a realistic simulation of complex multitask ADL (planning and preparing a meal). Though the CHI patients were significantly slow on one test and subject to interference on an attention test, they manifested no basic executive or memory deficit on the paper-pencil tests. However, the CHI patients manifested marked anomalies in the organization of behavior in the meal preparation task. While small sequences of actions were easily produced, large action sets could not be correctly executed. An outstanding difficulty in strategic planning and prospective memory, particularly time-based more than event-based, appears to be an important underpinning of the impairment of ADL observed in the CHI patients with frontal lobe lesions.     

Age-related effects in prospective memory are modulated by ongoing task complexity and relation to target cue

Two experiments examined the puzzling variation in the age-related patterns for event-based prospective memory tasks. Both experiments involved a famous faces ongoing task with a feature of the famous face as the target for the prospective memory task. In Experiment 1, a substantial age deficit was found on the prospective memory task when the cue was nonfocal (wearing glasses) to the ongoing task, replicating previous research, but this deficit was significantly reduced with a focal cue (first name John). In Experiment 2, the prospective memory cue (wearing glasses) was held constant and the demands of the ongoing task of naming faces were varied. The substantial age differences found with a nonfocal cue were eliminated when the ongoing task was made less challenging. The findings help reconcile the divergent age-related findings reported in the literature.     

Prospective memory in young and older adults: the effects of ongoing-task load

Prospective memory involves remembering to perform intended actions in the future. Previous work with the multinomial model of event-based prospective memory indicated that adult age-related differences in prospective-memory performance were due to the prospective (not the retrospective) component of the task (Smith & Bayen, 2006 , Journal of Experimental Psychology: Learning, Memory, and Cognition, 32, 623). However, ongoing-task performance was also lower in older adults in that study. In the current study with young and older adults, the difficulty of the ongoing task was manipulated by varying the number of colors per trial to create easier and harder versions of the ongoing task for each age group. The easier version included 2 colors per trial for older adults and 4 colors for young adults. The harder version included 4 colors for older adults and 6 colors for young adults. By adjusting the ongoing-task difficulty, older adults were able to perform the ongoing task as well or better than the young adults. Analyses with the multinomial model revealed that making the ongoing task easier for older adults (or more difficult for young adults) did not eliminate age-related differences in prospective-memory performance and the underlying prospective component.     

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.     

Planning and realization of complex intentions in traumatic brain injury and normal aging

The realization of delayed intentions (i.e., prospective memory) is a highly complex process composed of four phases: intention formation, retention, re-instantiation, and execution. The aim of this study was to investigate if executive functioning impairments are related to problems in the formation, re-instantiation, and execution of a delayed complex intention. In this context, it was another aim of the study to investigate the executive functioning hypothesis of cognitive aging in prospective memory performance. It was, therefore, explored if age-related prospective memory decline leads to similar decrements in the process of prospective remembering as executive functioning-related decline in young patients with traumatic brain injury. A group of patients with traumatic brain injury with retrospective memory within normal limits but impaired executive functions, a group of healthy older and a group of healthy younger adults completed a complex prospective memory task that allows for the separate assessment of the four phases of the prospective memory process. All groups showed a similarly high performance in the intention retention phase, whereas the patients with deficits in executive functioning and the older participants performed worse than the healthy young participants in the intention formation, re-instantiation and execution phases. The importance of executive functioning for prospective remembering in traumatic brain injury and normal aging is discussed.     

Prospective memory in young and older adults: The effects of task importance and ongoing task load

Remembering to perform an action in the future, called prospective memory, often shows age-related differences in favor of young adults when tested in the laboratory. Recently Smith, Horn, and Bayen (2012; Aging, Neuropsychology, and Cognition, 19, 495) embedded a PM task in an ongoing color-matching task and manipulated the difficulty of the ongoing task by varying the number of colors on each trial of the task. Smith et al. found that age-related differences in PM performance (lower PM performance for older adults relative to young adults) persisted even when older adults could perform the ongoing task as well or better than the young adults. The current study investigates a possible explanation for the pattern of results reported by Smith et al. by including a manipulation of task emphasis: for half of the participants the prospective memory task was emphasize, while for the other half the ongoing color-matching task was emphasized. Older adults performed a 4-color version of the ongoing color-matching task, while young adults completed either the 4-color or a more difficult 6-color version of the ongoing task. Older adults failed to perform as well as the young adults on the prospective memory task regardless of task emphasis, even when older adults were performing as well or better than the young adults on the ongoing color-matching task. The current results indicate that the lack of an effect of ongoing task load on prospective memory task performance is not due to a perception that one or the other task is more important than the other.     

Preliminary remarks on type of task and delay in children's prospective memory

This study investigated the extent to which the type of task influences children's prospective memory performance. 80 subjects, aged 7 to 11 yr. participated in an experiment in which the type of task (time-based vs event-based) and the retention interval (5 min. vs 10 min.) varied. The prospective memory task was embedded in a principal task lasting about 15 min. and required subjects perform an action at a given time or in response to a specific cue. Analysis indicated that the delay was associated with prospective memory performance only on a time-based task in which the intention has to be performed after 10 min. but not age. Analysis indicated also that time monitoring was associated with shorter latency between the target time and the execution of the intention on the time-based task. Implications were discussed.