Distinct and shared cognitive functions mediate event- and time-based prospective memory impairment in normal ageing

Prospective memory (PM) is the ability to remember to perform an action at a specific point in the future. Regarded as multidimensional, PM involves several cognitive functions that are known to be impaired in normal ageing. In the present study we set out to investigate the cognitive correlates of PM impairment in normal ageing. Manipulating cognitive load, we assessed event- and time-based PM, as well as several cognitive functions, including executive functions, working memory, and retrospective episodic memory, in healthy participants covering the entire adulthood. We found that normal ageing was characterised by PM decline in all conditions and that event-based PM was more sensitive to the effects of ageing than time-based PM. Whatever the conditions, PM was linked to inhibition and processing speed. However, while event-based PM was mainly mediated by binding and retrospective memory processes, time-based PM was mainly related to inhibition. The only distinction between high- and low-load PM cognitive correlates lies in an additional, but marginal, correlation between updating and the high-load PM condition. The association of distinct cognitive functions, as well as shared mechanisms with event- and time-based PM, confirm that each type of PM relies on a different set of processes.     

A meta-analytic review of prospective memory and aging

A meta-analysis of prospective memory (PM) studies revealed that in laboratory settings younger participants outperform older participants on tests of both time- and event-based PM (rs=-.39 and -.34, respectively). Event-based PM tasks that impose higher levels of controlled strategic demand are associated with significantly larger age effects than event-based PM tasks that are supported by relatively more automatic processes (rs=-.40 vs. -.14, respectively). However, contrary to the prevailing view in the literature, retrospective memory as measured by free recall is associated with significantly greater age-related decline (r=-.52) than PM, and older participants perform substantially better than their younger counterparts in naturalistic PM studies (rs=.35 and.52 for event- and time-based PM, respectively).     

Cognitive load and task condition in event- and time-based prospective memory: an experimental investigation

Prospective memory is memory for the realization of delayed intention. Researchers distinguish 2 kinds of prospective memory: event- and time-based (G. O. Einstein & M. A. McDaniel, 1990). Taking that distinction into account, the present authors explored participants' comparative performance under event- and time-based tasks. In an experimental study of 80 participants, the authors investigated the roles of cognitive load and task condition in prospective memory. Cognitive load (low vs. high) and task condition (event- vs. time-based task) were the independent variables. Accuracy in prospective memory was the dependent variable. Results showed significant differential effects under event- and time-based tasks. However, the effect of cognitive load was more detrimental in time-based prospective memory. Results also revealed that time monitoring is critical in successful performance of time estimation and so in time-based prospective memory. Similarly, participants' better performance on the event-based prospective memory task showed that they acted on the basis of environment cues. Event-based prospective memory was environmentally cued; time-based prospective memory required self-initiation.     

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.     

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.     

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.     

Exploring students' prospective memory inside and outside the lab

This study compared activity-based intentions with event- and time-based intentions. Forty-five participants completed a laboratory session that tested activity-, event-, and time-based prospective memory. Participants were then asked to keep a record of their planned academic and work-related activities for 1 week. Results revealed a main effect of context such that participants were better at performing intentions in the naturalistic setting than in the laboratory. A strong trend of intention type showed that event-based tasks were more likely to be performed than activity- and time-based tasks. An interaction of context and intention type suggested that participants were significantly better at performing time-based tasks in the naturalistic setting than in the lab. Nearly half of the participants reported using simple memory aids such as alarm clocks, parent or friend reminders, or other external cues. Strikingly, very few reported using electronic devices to aid their memory for future intentions.     

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.     

线索特征和提示对基于事件前瞻记忆的影响

前瞻记忆是一种记住在将来执行某个意向活动的记忆。研究采取2线索类型×2提示被试间设计探究了线索特征和有无提示对基于事件前瞻记忆的影响。结果表明:(1)提示使前瞻记忆的反应速度明显变慢,说明基于事件前瞻记忆的加工过程可能是自动完成的;(2)在具体线索条件下,被试完成进行中任务的速度显著快于概念线索条件下的速度。说明线索类型虽然没有影响到前瞻记忆加工,但是影响到了进行中任务的效率。     

Comparing time-based and event-based prospective memory over short delays

The current study compared monitoring in time- and event-based prospective memory (PM). Time- and event-based non-focal task instructions were given after a baseline block of a lexical decision ongoing task. Delay between instruction and presentation of PM cue/time was manipulated between-subjects to examine monitoring across short delays (1–6?min). Longer delays decreased performance in the event-based task, but not in the time-based task. This accuracy decline was accompanied by a decline in monitoring (as measured by PM cost to the ongoing task in the trials immediately before the PM cue was presented) between the 1 and 3?min delays. Monitoring was only evident for the time-based task at the 6?min delay as measured by PM cost to the ongoing task. Clock checks were also not affected by delay, but did increase in frequency as the response time neared. These results suggest that delay from the time of intention formation decreases both accuracy and monitoring in event-based tasks, but does not decrease accuracy or monitoring in time-based tasks.     

An investigation of the relations between stress and prospective memory

ABSTRACT

Prospective memory (PM), or remembering to perform intentions in the future, has important implications for one’s daily functioning and quality of life. Another common human experience is stress. Despite the significance and ubiquity of both PM and stress, our understanding of the relations between them is limited. The aim of the current study was to further delineate the relations between acute stress, chronic stress, non-focal event-based PM, and time-based PM. The results of the study revealed that acute stress induction after PM intention formation did not contribute to differences in non-focal event-based PM performance or time-based PM performance. However, self-reported chronic stress was significantly correlated with enhanced monitoring and time-based PM. In the present study, participants may have had optimal levels of enduring stress that contributed to enhanced monitoring behaviour (i.e. the prospective component of PM) and the ability to complete time-based intentions.     

背景任务刺激间的时距对前瞻干扰效应的影响

前瞻记忆是指形成和保持一个意向直到合适的情境或时间再执行的一种记忆任务。由于在执行背景任务的过程中保持和提取前瞻意向, 使成功执行前瞻记忆任务与加工背景任务之间存在着相互影响。保持前瞻记忆意向对背景任务的反应时和正确率有影响的现象称之为前瞻干扰效应。本研究通过操纵背景任务刺激间时距的两个实验, 考察了背景任务刺激间时距长度对时间性前瞻记忆和事件性前瞻记忆干扰效应量的对比关系的影响。结果发现随着背景任务刺激间时距缩短, 两类前瞻记忆干扰效应量的对比关系发生了变化, 且在背景任务刺激间时距长度不同的情况下执行时间性前瞻记忆任务时, 被试查看时钟的策略也有差异。提示了时间性前瞻记忆任务与事件性前瞻记忆任务认知加工机制上的不同。     

一种混合型前瞻记忆的加工机制

通过两个实验, 对以往研究忽略的一种基于事件进行反应、且具有时间线索的混合型前瞻记忆的加工过程进行考察。结果表明, 这种混合型的前瞻记忆可以通过控制加工或自动加工提取, 还可能两种加工交替存在, 被试在执行过程中, 根据时间信息, 有选择地、动态地将注意资源投入于不同时间段, 现有理论不能解释这种现象。对多重加工理论进行补充, 使之能够解释这种混合型前瞻记忆的加工机制。     

Prospective memory, emotional valence and ageing

Emotional factors have been found to be an important influence on memory. The current study investigated the influence of emotional salience and age on a laboratory measure of prospective memory (PM); Virtual Week. Thirty young and 30 old adults completed Virtual Week, in which the emotional salience of the tasks at encoding was manipulated to be positive, negative or neutral in content. For event-based, but not time-based tasks, positivity enhancement in both age groups was seen, with a greater number of positive PM tasks being performed relative to neutral tasks. There was no negativity enhancement effect. Older adults showed generally poorer levels of PM, but they also demonstrated greater beneficial effects of positive valence compared to young. These effects of emotion on PM accuracy do not appear to reflect the retrospective component of the task as a different pattern of emotion effects was seen on the recall of PM content. Results indicate that older adults' difficulties in prospective remembering can be reduced where the tasks to be remembered are positive.     

Memory deficits for non-amnestic mild cognitive impairment

Non-amnestic mild cognitive impairment (naMCI) is one of the clinical subtypes of mild cognitive impairment (MCI). However, the characteristics of memory deficits in naMCI as assessed by clinical neuropsychological evaluations are not clear. In this study, a battery of neuropsychological tests was administered to 122 cognitively normal controls (NC), 133 amnestic mild cognitive impairment (aMCI) patients, and 72 naMCI patients. The results showed that in individuals with naMCI, episodic memory, and other cognitive domains were impaired. The Prospective Memory Test (PMT) event-based prospective memory (EBPM), the Symbol Digit Modalities Test (SDMT) Accidental Memory, Stick test (ST) visuoconstructional memory, and ST Working Memory were impaired, yet did not reach the level of aMCI. Semantic memory was affected to a degree comparable with aMCI. Some functions like Auditory Verbal Learning Test (AVLT) recognition, and Judgment of Confidence (JOC) were maintained, as well as PMT Time-Based Prospective Memory (TBPM). This study verified that memory impairment among individuals with naMCI was mainly in memory functions mediated by the frontotemporal cortex.     

The role of white matter hyperintensities and medial temporal lobe atrophy in age-related executive dysfunctioning

Various studies support an association between white matter hyperintensities (WMH) and deficits in executive function in nondemented ageing. Studies examining executive functions and WMH have generally adopted executive function as a phrase including various functions such as flexibility, inhibition, and working memory. However, these functions include distinctive cognitive processes and not all may be affected as a result of WMH. Furthermore, atrophy of the medial temporal lobe (MTA) is frequently observed in ageing. Nevertheless, in previous studies of nondemented ageing MTA was not considered when examining a relationship between white matter and executive function. The goal of the present study was to examine how WMH and MTA relate to a variety of executive functions, including flexibility, fluency, inhibition, planning, set shifting, and working memory. Strong correlations were observed between WMH and MTA and most of the executive functions. However, only MTA was related to flexibility and set shifting performance. Regression analysis furthermore showed that MTA was the strongest predictor of working memory, after which no further significant association with WMH was noted. Alternatively, both MTA and periventricular hyperintensities independently predicted inhibition performance. These findings emphasize the importance of MTA when examining age-related decline in executive functioning.     

MPT模型在事件性前瞻记忆研究中的应用

前瞻性记忆是指对将要进行的活动或事件的记忆。前瞻记忆中,包含了前瞻成分和回溯成分。前人研究中,缺乏对前瞻成分和回溯成分有效的分离手段,使得对前瞻记忆机制的探讨缺乏深入挖掘。本文将MPT模型与Cohen等人的研究范式对比,分析了该模型在事件性前瞻记忆研究中的优势。文章对模型的理论基础,模型的主要内容,模型的数据计算方法,模型的效度以及模型的应用等几个方面进行了介绍,同时对模型使用中需要注意的问题进行了讨论。     

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.     

事件性前瞻记忆的加工机制：来自ERP的证据

采用事件相关电位技术,对前瞻记忆的加工机制——主要是执行前的加工机制进行研究。控制条件为单纯的背景任务,实验条件为背景任务含前瞻记忆任务,对两种条件下非靶线索的行为数据进行比较,结果表明实验条件下被试的反应时显著长于控制条件,可能说明两种条件的认知过程存在差异,这种差异在ERPs上主要体现为刺激呈现200ms以后,两种条件的波形和脑地形图存在显著差异。结果支持预备注意加工和记忆加工理论,也部分支持多重加工理论