Commission errors in delay–execute prospective memory tasks

Individuals frequently retrieve an intention, but the execution of the task needs to be delayed due to ongoing task demands - so-called delay-execute prospective memory (PM) tasks. We investigated commission errors in the delay-execute paradigm. Participants were told that a PM task is finished (PM task has been executed and is now finished for a final phase) or cancelled (PM task has been cancelled immediately after introduction). We observed commission errors and ongoing task performance in the final phase which included several irrelevant PM cues. In two experiments, we observed significantly more commission errors for cancelled compared to the finished intentions. In Experiment 2, commission errors were eliminated if the final phase required divided attention, regardless of PM task status. In addition, we observed significantly more PM cue interference on the ongoing task in the cancelled compared to the finished group, indicating that the PM task was retrieved in the cancelled group but not in the finished group. As retrieval and execution of the PM task were separated by a delay, the results indicate that commission errors are not always the result of a quick, spontaneous retrieval-execution sequence and may also occur when retrieval and execution are temporally separated.     

The Role of Interruptions and Contextual Associations in Delayed‐Execute Prospective Memory

We conducted three experiments to examine the dynamics of a delayed‐execute prospective memory task involving task interruptions. In the delayed‐execute paradigm, participants must delay a response until some future condition is met. After an intention was formed to a salient cue, an interruption reduced prospective memory relative to a no‐interruption condition. Prospective memory for cues encountered during an interrupting task was worse than for cues occurring before an interruption, but the location of the cue in either the ongoing task or the interruption did not affect prospective memory. Importantly, reinstating the prevailing context after the interruption alleviated the negative influence of the interruption. Providing participants with information about the future context for making the delayed‐execute response also alleviated some of these deficits presumably because participants could encode more specific features of the performance context. These results highlight the potential importance of contextual associations and reminders in completing everyday intentions successfully. Copyright © 2013 John Wiley & Sons, Ltd.     

Effects of ongoing task context and target typicality on prospective memory performance: the importance of associative cueing

Two experiments examined whether prospective memory performance is influenced by contextual cues. In our automatic activation model, any information available at encoding and retrieval should aid recall of the prospective task. The first experiment demonstrated an effect of the ongoing task context; performance was better when information about the ongoing task present at retrieval was available at encoding. Performance was also improved by a strong association between the prospective memory target as it was presented at retrieval and the intention as it was encoded. Experiment 2 demonstrated boundary conditions of the ongoing task context effect, which implicate the association between the ongoing and prospective tasks formed at encoding as the source of the context effect. The results of this study are consistent with predictions based on automatic activation of intentions.     

Effects of ongoing task context and target typicality on prospective memory performance: The importance of associative cueing

Two experiments examined whether prospective memory performance is influenced by contextual cues. In our automatic activation model, any information available at encoding and retrieval should aid recall of the prospective task. The first experiment demonstrated an effect of the ongoing task context; performance was better when information about the ongoing task present at retrieval was available at encoding. Performance was also improved by a strong association between the prospective memory target as it was presented at retrieval and the intention as it was encoded. Experiment 2 demonstrated boundary conditions of the ongoing task context effect, which implicate the association between the ongoing and prospective tasks formed at encoding as the source of the context effect. The results of this study are consistent with predictions based on automatic activation of intentions.     

Dismantling the “age–prospective memory paradox”: The classic laboratory paradigm simulated in a naturalistic setting

Previous research has identified “the age–prospective memory paradox”—that adult ageing results in reliably poorer performance on laboratory-based tasks of prospective memory (PM), but improved performance on such tasks carried out in real-life settings. We hypothesized that even in their everyday environment, older adults might be worse at PM tasks that are triggered during an experimenter-generated ongoing activity. The present study used a task that captured the key features of the classic laboratory paradigm, but which was completed in a setting that met key criteria to be considered naturalistic. In their everyday setting, participants' PM was assessed, with the cue to remember occurring either (a) during their day-to-day activities, or (b) during an experimenter-generated ongoing task. The results confirmed previous naturalistic findings, in showing that older adults (n = 28) exhibited better PM than their younger counterparts (n = 65) when prompted during their everyday activities. However, older adults were also then subsequently less likely to show effective PM during experimenter-generated ongoing activity. Reproducing the paradox within a single dataset, these data indicate that older adults can effectively act on intentions during everyday activities, but have difficulty in prospective remembering during experimenter-generated ongoing tasks.     

Effects of delay of prospective memory cues in an ongoing task on prospective memory task performance

To address the mixed results reported in previous studies, the present experiments examined forgetting in prospective memory (PM) by manipulating the delay between the PM instructions and cue presentation in event-based PM tasks. PM performance was measured for delays of 2–20 min in Experiment 1 and for delays of approximately 1–10 min in Experiment 2. Experiment 2 included both focal and nonfocal PM tasks, and speed on the ongoing task was measured to examine evidence for monitoring processes across the delays tested. The results suggest that nonfocal PM performance follows a nonlinear forgetting function (i.e., rapid decline for shorter delays and slower decline for longer delays) when tested over delays from 1 to 20 min. No effect of delay was seen for the focal task tested in Experiment 2 from 1 to 10 min. In Experiment 2, ongoing-task costs were also found for the first delay but not for longer delays, suggesting that monitoring was significantly reduced between 1 and 2.5 min of the ongoing-task trials.     

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.     

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.     

绝对重要性和认知负荷影响基于事件的前瞻记忆

操作前瞻记忆任务的重要性的方式有两种,研究发现相对重要性会造成进行中任务的损耗,而绝对重要性的研究较少且结果不尽一致,这种差异可能与进行中任务占用认知资源的情况有关。我们使用绝对重要性的指导语来操纵前瞻记忆任务的重要性高或者低,并且以Stroop任务作为进行中任务,来考察绝对重要性和认知资源占用的交互影响。结果发现,在进行中任务一致条件下,绝对重要性的增高促进了进行中任务的完成;而不一致条件下,则会阻碍进行中任务的完成。这说明,进行中任务的认知资源变化与前瞻记忆任务重要性对进行中任务的影响有着交互调节作用。     

Conceptual and perceptual processes in prospective remembering: differential influence of attentional resources

Does prospective remembering rely on strategic, attentionally demanding processes? We report three experiments suggesting that the extent to which attentional processes are required varies according to the character of ongoing task processing. Study-test changes in the semantic context of targets had a negative effect on prospective memory performance when participants were engaged in a conceptually focused (sentence verification) task (Experiment 1). Similarly, prospective remembering was lower following study-test changes in perceptual format (font) in the context of a perceptually focused (readability rating) ongoing task (Experiment 2). However, although dividing attention at retrieval had a negative effect during the performance of an ongoing conceptual task (Experiments 1 and 3), it had no effect during an ongoing perceptual task (Experiments 2 and 3). Thus, both perceptual and conceptual process are implicated in prospective remembering, but the processing focus of the task in which remembering should occur may mediate the requirement for strategic processes. These findings suggest that more than one retrieval route is available for prospective remembering and that selection of the route depends on the nature of the task and the processing that occurs at encoding and retrieval.     

Context-specific prospective-memory processing: Evidence for flexible attention allocation adjustments after intention encoding

Prospective memory (PM) is remembering to fulfill intentions in the future. Interference of unfulfilled intentions with ongoing activities reflects the allocation of attention to the PM task. Prior research has shown that, when people know in which specific context PM cues will occur, attention allocation is adaptive, with slower responses in the PM-relevant context. We examined whether people flexibly adjust their attention allocation when the PM–context association is unknown at intention encoding and must be learned on-task. Different stimulus shapes represented contexts in an ongoing task, with PM cues only occurring in trials with one specific shape. Participants informed about the PM-relevant shape responded more slowly on trials with this shape. Participants instructed that only one, unspecified shape was PM-relevant learned the PM–context association and also allocated attention flexibly, depending on context relevance. However, participants with no context-related information at intention encoding failed to learn the PM–context association, resulting in inflexible attention allocation and poorer PM performance. The present study provides evidence that people can flexibly update their attention-allocation policy, and thereby optimize their PM performance after initial intention encoding, but self-guided learning of intention–context associations appears to be limited.     

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.     

Forgetting of intentions in demanding situations is rapid

Demanding work settings often require the deferral of intended actions. In 3 experiments, participants were to withhold a response until they encountered a task change (which occurred 5, 15, or 40 sec later). To approximate highly demanding settings, the experimenters sometimes divided attention during the delay period. During some of the delays the experimenters interrupted the participants with an additional task (Experiment 1). Demanding conditions as well as interruptions revealed rapid forgetting of intentions at levels that would be considered significant in applied settings. Experiments 2 and 3 showed that this rapid forgetting was not reduced by strategic rehearsal and implementation intention strategies. The results suggest that maintaining intentions over brief delays is not a trivial task for the human cognitive system.     

Delaying execution of intentions: overcoming the costs of interruptions

In real-world settings, execution of retrieved intentions must often be briefly delayed until an ongoing activity is completed (delayed-execute prospective memory tasks). Further, in demanding work settings, the ongoing activity itself can be interrupted. Experiment 1 examined the effects of the delay length (5, 15, 40 s), the presence of an interruption within that delay, and the length of the interruption on prospective memory performance. Delay length did not significantly affect performance, but interruptions produced significant decrements in performance relative to a delay alone. The length of the interruptions (10 vs. 20 s) did not significantly affect performance. Experiment 2 replicated the negative effects of interruptions, and found that these effects could be overcome with a simple external mnemonic. We suggest that in demanding work environments where interruptions are likely, external cues are advisable, especially where prospective memory failures have critical consequences. Copyright © 2004 John Wiley & Sons, Ltd.     

Resistance to the impact of interruptions during multitasking by healthy adults and dysexecutive patients

Two experiments (one with healthy adult volunteers and the other with controls and dysexecutive patients) assessed the impact of interruptions on a novel test of multitasking. The test involved switching repeatedly between four tasks (block construction, bead threading, paper folding, alphabetical searching) over a 10 min period. In Experiment 1, there were four groups of 20 healthy participants. One group attempted multitasking with no interruption, a second group was interrupted early in the test, a third group late in the test and a fourth group was interrupted both early and late. Interruption involved carrying out a fifth, unexpected task for a period of 1 min before returning to the four main tasks. There was no difference in multitasking performance between the groups. In Experiment 2 the participants were seven dysexecutive patients and 14 age-matched controls. A repeated measures approach was employed to assess the impact of two interruptions (early and late) for both groups. Contrary to predictions, the patients as well as controls were resistant to the effects of interruptions, despite their clearly impaired multitasking performance. These results suggest that the ability to deal with interruptions may be separable from the ability to organise and execute multiple tasks within a limited time frame.     

Strategic offloading of delayed intentions into the external environment

In everyday life, we often use external artefacts such as diaries to help us remember intended behaviours. In addition, we commonly manipulate our environment, for example by placing reminders in noticeable places. Yet strategic offloading of intentions to the external environment is not typically permitted in laboratory tasks examining memory for delayed intentions. What factors influence our use of such strategies, and what behavioural consequences do they have? This article describes four online experiments (N?=?1196) examining a novel web-based task in which participants hold intentions for brief periods, with the option to strategically externalize these intentions by creating a reminder. This task significantly predicted participants' fulfilment of a naturalistic intention embedded within their everyday activities up to one week later (with greater predictive ability than more traditional prospective memory tasks, albeit with weak effect size). Setting external reminders improved performance, and it was more prevalent in older adults. Furthermore, participants set reminders adaptively, based on (a) memory load, and (b) the likelihood of distraction. These results suggest the importance of metacognitive processes in triggering intention offloading, which can increase the probability that intentions are eventually fulfilled.     

Processing strategies and secondary memory in very rapid forgetting

When a memory test is unexpected, recall performance is quite poor at retention intervals as short as 2–4 seconds. Orienting tasks that change encoding conditions are known to affect forgetting in such “very rapid forgetting” paradigms where people are misled to believe that recall will not be required. We evaluated the hypothesis that differences in forgetting among orienting tasks are attributable to contributions of secondary memory during encoding in two experiments. In Experiment 1, short-term recall performance was inversely related to task demands during encoding, although long-term memory performance was not. Task demands were assessed by making the duration of stimulus presentation dependent on the time required to perform three different orienting tasks. In Experiment 2, we compared performance of that variable-length stimulus presentation to the fixed-length presentation used in most prior research. The results suggested that additional encoding or rehearsal time does not have an appreciable impact on short-term performance. Thus, differences in forgetting appeared to be a function of the contribution of secondary memory rather than a function of the time available to engage in primary memory rehearsal strategies.     

Stimulus context and duration discrimination

The ability of human observers to discriminate duration was assessed in two types of tasks: (1) pulse tasks, in which the observer compared the duration of two brief increments in an ongoing sinusoid, and (2) gap tasks, in which the observer compared the duration of two brief interruptions in an ongoing sinusoid. Performance in these tasks was assessed in three different contexts: noise alone, noise plus continuous sinusoids, and noise plus continuous sinusoids chosen to induce a pitch segregation effect. Performance in the pulse task was independent of the changes in context; however, performance in the gap task changed as a function of context condition. There was a large decrement in the observers’ ability to discriminate duration when the stimulus ensemble induced the pitch segregation effect. The results are discussed in terms of the relationship between duration discrimination and stimulus variations which do not carry duration information.     

Is task interference in event-based prospective memory dependent on cue presentation?

Whether having an intention produces a performance cost to ongoing activities (task interference) is central to theoretical claims regarding the mechanisms underlying cue detection in event-based prospective memory. Recent evidence suggests that task interference primarily reflects an attention allocation policy stored in memory when intentions are encoded. The present study examined whether these policies can change with ongoing task experience. In Experiment 1, task interference was more greatly reduced when expected cues were not presented than when they were. Experiment 2 replicated this effect when the importance of the prospective memory task was emphasized. In Experiment 3, task interference decreased with time, and this decrease was greater when expected cues were not presented than when they were. Cue presentation is crucial to maintenance of attention allocation policies established by task instructions. This is the first article to demonstrate changes in task interference with ongoing task experience without forewarning individuals of the relevance of upcoming ongoing task trials to 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。