Age-related differences and complexity of ongoing activities in time- and event-based prospective memory

Aging is presumed to disrupt self-initiated processing, and a time-based prospective memory task (i.e., action to be performed at a particular time) entails more self-initiated activities than an event-based prospective memory task (i.e., action to be performed to a critical event). Accordingly, older participants are predicted to be particularly bad in a time-based prospective memory task. However, the prediction is not always confirmed. Self-initiated activities entail central executive functioning. We therefore predicted the age deficit to emerge more clearly when the performance on the ongoing task also involved more central executive functioning. Time-based prospective memory among older adults collapsed when the complexity of the ongoing task increased. However, an age deficit was also obtained when the pacing of the event-based prospective memory task was high because of the general slowing of functioning by older adults.     

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.     

加工焦点性和任务负荷对不同认知方式大学生前瞻记忆的影响

采用双任务范式,探讨了加工焦点性和进行中任务负荷对不同认知方式大学生前瞻记忆的影响。包括两个实验:实验一探讨进行中任务与前瞻记忆任务加工的焦点性和加工类型的一致性对不同认知方式大学生前瞻记忆的影响;实验二探讨进行中任务负荷对不同认知方式大学生在在焦点加工和非焦点加工条件下前瞻记忆的影响。结果显示:焦点加工条件下的前瞻记忆成绩高于非焦点加工,且不受进行中任务负荷的影响;不管进行中任务与前瞻记忆任务的加工类型是否一致,在进行中任务负荷较高且非焦点加工条件下,场独立大学生的前瞻记忆成绩高于场依存大学生。本研究结果支持多重加工理论。     

When remembering the past suppresses memory for future actions

Remembering planned actions at the correct time in the future is an integral component of prospective cognition. Recent studies on future remembering have led to suggestions that prospective cognition might be based on past experience. To test this hypothesis, we focused on retrieval-induced forgetting (RIF), which usually indicates that remembering past events suppresses memory for related but different past events. The current study assessed RIF in two kinds of event-based prospective memory (PM) tasks using either focal or non-focal cues for ongoing tasks. Participants studied six members from each of eight taxonomic categories and then practiced recalling three of the six members from four of the eight categories using category-stem cues. This retrieval practice suppressed the detection of non-practiced members of the practiced categories during the PM task with non-focal cues (Experiment 1) but not with focal cues (Experiment 2). The results suggest that recall of certain items inhibits the function of the others as PM cues, but only if the PM task does not largely share its processing with the ongoing task.     

Prior task experience and comparable stimulus exposure nullify focal and nonfocal prospective memory retrieval differences

We explored the nature of focal versus nonfocal event-based prospective memory retrieval. In the context of a lexical decision task, people received an intention to respond to a single word (focal) in one condition and to a category label (nonfocal) for the other condition. Participants experienced both conditions, and their order was manipulated. The focal instruction condition was a single word presented multiple times. In Experiment 1, the stimuli in the nonfocal condition were different exemplars from a category, each presented once. In the nonfocal condition retrieval was poorer and reaction times were slower during the ongoing task as compared to the focal condition, replicating prior findings. In Experiment 2, the stimulus in the nonfocal condition was a single category exemplar repeated multiple times. When this single-exemplar nonfocal condition followed in time the single-item focal condition, focal versus nonfocal performance was virtually indistinguishable. These results demonstrate that people can modify their stimulus processing and expectations in event-based prospective memory tasks based on experience with the nature of prospective cues and with the ongoing task.     

Motivation,depression, and naturalistic time-based prospective remembering

This study investigated the effect of a motivational manipulation on naturalistic time-based prospective memory (PM) task performance. The association between depression and PM task performance was also investigated. First-year psychology students were required to send mobile phone text messages (SMSs) at a specific time 3 days and 6 days after an initial meeting. During the delay period participants recorded details of the retrieval whenever they remembered the SMS task. Participants given the incentive of extra course credit (motivation condition) outperformed their counterparts on the PM tasks, and showed a greater increase in the reported frequency of self-initiated retrievals on target days. Depression was negatively correlated with PM task performance. The findings suggest that motivational instructions impact the controlled processes underlying PM.     

Enhanced recognition of words previously presented in a task with nonfocal prospective memory requirements

Remembering to perform deferred actions when events are encountered in the future is referred to as event-based prospective memory. Individuals can be slower to respond to ongoing tasks when they have prospective memory task requirements. These costs are interpreted as evidence for cognitive control processes allocated to the prospective memory task, but we know little about these processes. In the present article, the recognition of nontargets previously presented in an ongoing task with prospective memory task requirements provided evidence for the differential processing of individual ongoing task items. Participants performed a lexical decision task, where some participants were required to make an alternative prospective memory response either to a specific word (focal) or to exemplars of a category (nonfocal). Participants were slower to respond to the ongoing task in the nonfocal conditions than in the control condition (costs), regardless of whether or not prospective memory task importance was emphasized. Participants were also slower to respond to the ongoing task in the focal conditions than in the control condition, but only when prospective memory task importance was emphasized. This task was followed by a surprise recognition memory test in which nontarget words from the lexical decision task were intermixed with new words. Focal conditions, but not nonfocal conditions, showed better discrimination on the recognition task, as compared with the control condition. Participants in nonfocal conditions mapped the semantic features of the ongoing task letter strings onto the semantic features of their prospective memory category, and this elaboration in the processing of individual nontargets increased incidental learning and produced the recognition benefit.     

On the relationship between effort toward an ongoing task and cue detection in event-based prospective memory

In recent theories of event-based prospective memory, researchers have debated what degree of resources are necessary to identify a cue as related to a previously established intention. In order to simulate natural variations in attention, the authors manipulated effort toward an ongoing cognitive task in which intention-related cues were embedded in 3 experiments. High effort toward the ongoing task resulted in decreased prospective memory only when the cognitive processing required to identify the cue was similar to the cognitive processing required to complete the ongoing activity. When the required processing was different for the 2 tasks, cue detection was not affected by manipulated effort, despite there being an overall cost to decision latencies in the ongoing tasks from possessing the intention. Resource allocation policies and factors that affect them are proposed to account for ongoing vs. prospective memory task performance.     

Acute pain disrupts prospective memory cue detection processes

Prospective memory refers to the planning, retention, retrieval, and execution of intentions for future behaviours and it is integral to the enterprise of daily living. Although prospective memory relies upon retrospective memory and executive processes often disrupted by pain, limited research has explored the influence of acute or chronic pain on the ability to complete prospective memory tasks. In the present study we investigated the influence of acute pain on prospective memory tasks that varied in their demands on executive processes (i.e., non-focal versus focal prospective memory cues). Complex-span working memory tasks were also administered to examine whether individual differences in working memory capacity moderated any negative impact of pain on prospective memory. Acute pain significantly impaired prospective memory performance in conditions that encouraged non-focal strategic processing of prospective memory cues, but not in conditions that encouraged more spontaneous focal processing. Individual differences in working memory capacity did not moderate the effect of acute pain on non-focal prospective memory. These findings provide new insights into prospective memory dysfunction created by painful experiences.     

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.     

Fitting an ex-Gaussian function to examine costs in event-based prospective memory: Evidence for a continuous monitoring profile

Event-based prospective memory (PM) tasks require individuals to remember to perform a deferred action when a target event occurs. PM task requirements can slow ongoing task responses on non-target trials (‘costs’) under conditions where the defining features of targets are non-focal to the ongoing task, which is indicative that individuals have allocated some form of cognitive control process to the PM task. Recent fits of the ex-Gaussian mathematical function to non-target trial response distributions by prior studies have indicated that these control processes are transiently allocated. In the current paper, fits of the ex-Gaussian function to data reported by Loft and Humphreys (2012) demonstrate a shift in the entire response time distribution (μ) and an increase in skew (τ) for a non-focal PM condition required to remember to make a PM response if presented with category exemplars, compared to a control condition. This change in μ is indicative of a more continuous PM monitoring profile than that reported by prior studies. In addition, within–subject variability in μ was reliably correlated with PM accuracy, suggesting that these control processes allocated on a regular basis were functional to PM accuracy. In contrast, when the ongoing task directed attention to the defining features of targets (focal PM) there was a trend level increase in μ, but the within–subject variability in μ was not correlated with PM accuracy, consistent with the theoretical premise that focal PM tasks are not as dependent on cognitive control as non-focal PM tasks.     

Individual differences in event-based prospective memory: Evidence for multiple processes supporting cue detection

The multiprocess view proposes that different processes can be used to detect event-based prospective memory cues, depending in part on the specificity of the cue. According to this theory, attentional processes are not necessary to detect focal cues, whereas detection of nonfocal cues requires some form of controlled attention. This notion was tested using a design in which we compared performance on a focal and on a nonfocal prospective memory task by participants with high or low working memory capacity. An interaction was found, such that participants with high and low working memory performed equally well on the focal task, whereas the participants with high working memory performed significantly better on the nonfocal task than did their counterparts with low working memory. Thus, controlled attention was only necessary for detecting event-based prospective memory cues in the nonfocal task. These results have implications for theories of prospective memory, the processes necessary for cue detection, and the successful fulfillment of intentions.     

执行意向影响事件性前瞻记忆的加工机制

本研究旨在探究不同执行意向编码形式对前瞻记忆加工机制的影响是否存在差异。结果显示在低认知负荷下,混合编码效果最好,仅执行意向编码次之,标准编码效果最差,而在高认知负荷下三种编码效果无差异。眼动指标显示在低认知负荷下混合编码的注视点数量最多,总注视时间最长;在混合编码条件下进行中任务和前瞻记忆任务的总注视时间均长于仅执行意向编码和标准编码。结果说明,执行意向编码容易受认知负荷的影响;在低认知负荷下混合编码的被试对任务刺激进行更多的监控和加工,而仅执行意向编码促进前瞻记忆任务的自动化加工。     

The influence of partial-match cues on event-based prospective memory

In event-based prospective memory tasks people form an intention to respond when an environmental cue signals that conditions are appropriate to fulfil an intended activity. In the ongoing activity the authors embedded partial-match cues that only partially, but not completely, satisfied the conditions required to make a prospective response. The consequence of encountering these partial-match cues was to increase responses to appropriate prospective memory cues encountered later. This outcome occurred both with semantic and orthographic cues, but only the former led to longer processing latencies of the partial-match cues. This asymmetry suggests that partial-match cues may not need to be processed consciously in order to benefit event-based prospective memory. A parametric manipulation of the number of partial-match cues resulted in numerically but not statistically better prospective memory. Consequently, partial-match cues may function as overt reminders of the intention to respond or they may serve to engage participants in self-initiated remindings of the intention.     

Varying the importance of a prospective memory task: differential effects across time- and event-based prospective memory

Only few studies have addressed the issue of task importance in prospective memory. Most of them, but not all, have shown that perceived task importance does improve prospective memory performance. However, there is little understanding of (1) the conditions under which importance of the prospective memory task makes a difference in performance and (2) the mechanisms by which perceived task importance has an effect on prospective memory performance. The present study reports two experiments that manipulate task importance in a time-based and an event-based prospective memory paradigm. Results show that importance has an effect on the time-based but not on the event-based task. Further analyses of the performance in the cover tasks as well as the monitoring behaviour indicate that importance improves prospective memory to the degree the task requires the strategic allocation of attentional resources.     

Threat-related processing supports prospective memory retrieval for people with obsessive tendencies

Obsessive-compulsive disorder can result in a variety of deficits to cognitive performance, including negative consequences for attention and memory performance. The question addressed in the current study concerned whether this disorder influenced performance in an event-based prospective memory task. The results from a subclinical population indicated that, relative to non-anxious controls and mildly depressed controls, people with obsessive-compulsive tendencies (washing compulsions) incur decrements in remembering to respond to cues related to a neutral intention (respond to animals). This deficit was ameliorated by giving the subclinical group an intention about a threat-related category (respond to bodily fluids) and cueing them with concepts that they had previously rated as particularly disturbing to them. Thus, their normal attentional bias for extended processing of threat-related information overcame their natural deficit in event-based prospective memory.     

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.     

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.     

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.