Target preexposure eliminates the effect of distraction on event-based prospective memory

Prospective memory is critical to everyday functioning and can be vulnerable to distraction. We conducted an experiment to explore whether we could buffer prospective memory against distraction. For half the participants, we preexposed stimuli that were later designated as prospective memory targets. Then, all participants performed an ongoing task (in which the prospective memory task was embedded) under standard and high attentional demand (i.e., under full and divided attention). Target preexposure improved prospective memory and eliminated the significant divided attention effect. Thus, target preexposure seems to buffer prospective memory against the disruptive effect of dividing attention. Moreover, target preexposure seemed to help participants to respond with the correct intended action. This result implies that preexposure to the target stimuli facilitated the encoding of an association between the target stimuli and the intended action, perhaps promoting relatively more reflexive retrieval and thereby buffering prospective memory against distraction.     

Prospective remembering: Perceptually driven or conceptually driven processes?

Converging experimental operations and several prospective memory tasks were used across three experiments to determine the extent to which prospective remembering is supported by datadriven versus conceptually driven processes. In all experiments, subjects were asked to perform an action when a target item later occurred. When the semantic context changed from encoding to test, prospective memory significantly declined (Experiment 1). When the target event (the item, which in its subsequent appearance in the experiment was the signal to perform the action) was presented as a word (relative to picture presentation, Experiment 2) or was encoded nonsemantically (relative to semantic encoding, Experiment 3), there was a decline in prospective memory performance. Dividing attention during prospective memory retrieval substantially reduced prospective memory performance (Experiment 3). The results of this research indicated that prospective memory is largely conceptually driven, and it behaves more similarly to direct rather than indirect conceptual tests. We suggest that prospective remembering of the type studied here is mediated by a reflexive episodic associative memory system as proposed by Moscovitch (1994).     

Normal aging and prospective memory

We develop a laboratory paradigm for studying prospective memory and examine whether or not this type of memory is especially difficult for the elderly. In two experiments, young and old subjects were given a prospective memory test (they were asked to perform an action when a target event occurred) and three tests of retrospective memory (short-term memory, free recall, and recognition). From the perspective that aging disrupts mainly self-initiated retrieval processes, large age-related decrements in prospective memory were anticipated. However, despite showing reliable age differences on retrospective memory tests, both experiments showed no age deficits in prospective memory. Moreover, regression analyses produced no reliable relation between the prospective and retrospective memory tasks. Also, the experiments showed that external aids and unfamiliar target events benefit prospective memory performance. These results suggest some basic differences between prospective and retrospective memory.     

A two‐process model of strategic monitoring in event‐based prospective memory: Activation/retrieval mode and checking

Theorists have suggested that individuals may remember to execute event‐based intended actions by deploying executive or attentional resources to monitor for the markers or target events that indicate that it is appropriate to execute the intended actions (e.g., McDaniel & Einstein, 2000; Shallice & Burgess, 1991), but these strategic monitoring views are not specific about the processes that strategic monitoring entails. A more specific idea is outlined here (see also Guynn, 2001) and an experiment with results consistent with this view is reported. According to this two‐process view, strategic monitoring entails maintaining the cognitive system in a prospective memory retrieval mode, which may be mediated by increased activation of the prospective memory representation, plus checking whether the circumstances to execute the intended action are present. In the current experiment, concurrent task impairment on nontarget trials, on which participants were instructed to press a key if they saw a target event (i.e., experimental trials), relative to trials on which participants were not instructed to press a key if they saw a target event (i.e., control trials), provided a footprint of strategic monitoring. An interaction of trial type and whether the experimental and control trials alternated or were blocked revealed greater impairment on experimental trials relative to control trials when the trials were blocked than when the trials alternated. Performance on experimental trials did not vary whether the trials alternated or were blocked, while performance on control trials was significantly worse when the trials alternated than when the trials were blocked. The results are consistent with the two‐process view and the idea that participants maintained a retrieval mode/activation and checked on experimental trials, neither maintained a retrieval mode/activation nor checked on blocked control trials, and maintained a retrieval mode/activation but did not check on alternating control trials.     

Prospective memory: When reminders fail

A frequent assumption in the area of prospective memory is that a reminder to do an activity in the future improves the likelihood of doing the activity. The results of four experiments indicated, however, that the most general version of this assumption is incorrect. Subjects were either reminded of a prospective memory task several times during a retention interval or not reminded of the prospective memory task. The most effective reminders referred both to the prospective memory target events and to the intended activity. Reminders that referred only to the target events did not improve prospective memory (relative to a no-reminder control). Reminders that referred only to the intended activity did improve prospective memory, but not to the level of reminders that referred both to the target events and to the intended activity. Instructions to imagine oneself performing the prospective memory task did not further improve prospective memory. Neither the delay between the prospective memory instructions and the prospective memory cover task nor the delay between a reminder and a prospective memory target event significantly influenced performance. The results, which are discussed in terms of theoretical and practical implications, support a new theory of prospective memory and suggest surprising conditions under which reminders fail to benefit prospective memory.     

Multiple processes in prospective memory retrieval: factors determining monitoring versus spontaneous retrieval

Theoretically, prospective memory retrieval can be accomplished either by controlled monitoring of the environment for a target event or by a more reflexive process that spontaneously responds to the presence of a target event. These views were evaluated in Experiments 1-4 by examining whether performing a prospective memory task produced costs on the speed of performing the ongoing task. In Experiment 5, the authors directly tested for the existence of spontaneous retrieval. The results supported the multiprocess theory (M. A. McDaniel & G. O. Einstein, 2000) predictions that (a) spontaneous retrieval can occur and can support good prospective memory and (b) depending on task demands and individual differences, people rely to different degrees on monitoring versus spontaneous retrieval for prospective remembering.     

Discrepancy-plus-search processes in prospective memory retrieval

In the present study, we investigated the processes underlying prospective memory (PM) retrieval, focusing specifically on two possible spontaneous processes: discrepancy-plus-search and familiarity. Discrepancy was elicited by orthogonally manipulating the processing difficulties of the PM targets and the nontargets. Participants performed a PM task while solving anagrams with two levels of difficulty (easy or difficult). Assuming that the ease of processing easy anagrams would heighten a sense of familiarity, the familiarity view predicted better PM performance with easy anagrams as the PM targets. In contrast, the discrepancy-plus-search view predicted higher PM performance for the PM targets that were anagrams whose difficulty level mismatched that of the surrounding nontargets, as compared to PM targets whose difficulty matched that of the surrounding nontargets. This prediction was based on the idea that mismatching rather than matching difficulty levels would create discrepancy, thereby signaling significance for the target. Participants were more likely to perform the PM task for PM targets that were discrepant, supporting the discrepancy-plus-search view.     

前瞻记忆的理论模型综述

前瞻记忆是相对于回溯记忆提出的一种特殊的长时记忆,是指记住在将来某个恰当的时间执行先前意向的行为。本文介绍了近年来研究者提出的前瞻记忆认知和提取机制的理论模型,并对其做了评述。最后,本文针对目前研究中的薄弱环节尝试性地提出了今后前瞻记忆研究进一步发展的方向。     

Disentangling executive functions and memory processes in event‐based prospective remembering after brain damage: A neuropsychological study

Successful prospective remembering (PR) comprises at least two components: one retrospective component that refers to the encoding and retrieval of the content of the intention and a second prospective component that involves the retrieval of the intended action at the appropriate moment. Whereas the retrospective component is very similar to memory skills like learning and retention of new information, the prospective component is thought to rely mainly on executive function. Head injuries can disturb PR during both of these stages. To disentangle the relative impact of executive functions and retrospective memory processes on PR we embedded a PR task in a 2‐back verbal working memory paradigm. Fifty‐six neurological patients with brain damage of various aetiologies were divided pre‐experimentally into four groups on the basis of their delayed recall Index in the Wechsler Memory Scale‐Revised (WMS‐R, indicating absence or presence of deficits in retrospective memory functions) and their age‐corrected score in the Behavioural Assessment of the Dysexecutive Syndrome (BADS, indicating absence or presence of deficits in executive functions). Additionally, 19 controls matched for age and education were examined. We found that patients with deficits in executive functions detected fewer cues than any other group irrespective of their retrospective memory performance. However, eight patients with severe anterograde memory deficits could retain neither the intention nor its content. Thus, intactness of the retrospective component seems to be a necessary but not sufficient prerequisite for successful prospective remembering. For the execution of the intended action itself executive functions play a critical role.     

编码方式、认知负荷和线索数量对前瞻记忆的影响

采用2（编码方式：执行意向、练习）×2（认知负荷：高、低）×2（线索数量：单一线索、多线索）的混合设计探讨在不同认知负荷和线索数量下两种编码方式对前瞻记忆的影响。结果表明：认知负荷和编码方式交互作用显著,在高认知负荷条件下,练习编码显著好于执行意向编码;线索数量和编码方式交互作用显著,在多线索条件下,练习编码显著好于执行意向编码。说明执行意向编码更容易受认知负荷和线索数量的影响。研究支持了预备注意与记忆加工理论。     

Prospective memory: Effects of divided attention on spontaneous retrieval

We examined the effects of divided attention on the spontaneous retrieval of a prospective memory intention. Participants performed an ongoing lexical decision task with an embedded prospective memory demand, and also performed a divided-attention task during some segments of lexical decision trials. In all experiments, monitoring was highly discouraged, and we observed no evidence that participants engaged monitoring processes. In Experiment 1, performing a moderately demanding divided-attention task (a digit detection task) did not affect prospective memory performance. In Experiment 2, performing a more challenging divided-attention task (random number generation) impaired prospective memory. Experiment 3 showed that this impairment was eliminated when the prospective memory cue was perceptually salient. Taken together, the results indicate that spontaneous retrieval is not automatic and that challenging divided-attention tasks interfere with spontaneous retrieval and not with the execution of a retrieved intention.     

任务规律性对前瞻记忆的影响

采用混合实验设计,结合行为和眼动数据,探讨任务规律性对前瞻记忆的影响。行为结果显示规律已知条件下前瞻记忆成绩显著高于规律未知和无规律条件,规律未知条件下的前瞻记忆成绩在靶线索之后刺激上有高于无规律条件的趋势;眼动结果显示规律已知条件下的注视点最多,首次注视时间最长。结果说明:(1)任务规律性对前瞻记忆成绩具有促进作用;(2)任务规律性促进了对前瞻记忆任务的自动化加工;(3)在规律已知条件下前瞻记忆的加工过程呈现出动态交替的特点。     

Direct and indirect memory tests: What they reveal about age differences in interference

The effects of interference on memory in younger and older adults were examined in a series of three experiments. In the study task, subjects were presented with a series of sentences, each having both a target, to-be-remembered ending, and a nontarget ending. Older adults showed equal priming of targets and nontargets on an indirect memory test (Experiment 1), whereas younger adults showed greater priming of the targets. In contrast, on direct memory tests (Experiments 2 and 3) both age groups were more accurate for targets than nontargets. This pattern of results is interpreted as evidence that age differences in interference involve selective attention mechanisms, but not elaborative rehearsal processes.     

The costs of target prioritization and the external requirements for using a recall-to-reject strategy in memory exclusion tasks: a meta-analysis

In event-related potential (ERP) studies, the left-parietal old/new effect is commonly considered as a neural correlate of recollection. In memory exclusion tasks, the effect is usually observed when the targeted information is identified, but it is not necessarily present when studied items are rejected as nontargets. Interestingly, both the presence and the absence of such old/new effects to nontargets have been regarded as indicator for strategic retrieval. We reviewed previous ERP studies using memory exclusion tasks to analyze the reaction time (RT) pattern in such studies, as well as the influence of task difficulty on the occurrence of nontarget retrieval. We identified 44 test conditions, reported in 24 studies, and subjected the behavioral data to a meta-analysis. The RTs to correctly rejected new items were shorter than the RTs to hits, in particular in studies that required differentiating conceptual or perceptual information at test. When the retrieval of target information was prioritized, RTs to nontargets were delayed relative to targets. Without such prioritization, no such RT differences were observed. For test conditions with nontarget retrieval, the retrieval accuracy was poorer compared with test conditions without such retrieval. The findings support previous studies that claimed that nontarget retrieval becomes more likely when target retrieval is difficult, but the strong overlap in task difficulty between conditions with and without nontarget retrieval indicates that other, partly yet to-be-identified factors contribute to the occurrence of nontarget retrieval as well.     

Implementation intentions facilitate prospective memory under high attention demands

An implementation intention is a planning technique that involves specifying a situation for initiating an intended action and linking these specific cues to the intention. In two experiments with young adults, we found significant increases in prospective memory with implementation intentions. With an implementation intention, but not with standard instructions, prospective memory performance was maintained under demanding attentional conditions (Experiment 2). Ongoing task performance did not decline, however, in relation with a no prospective memory control. Positive effects were not observed when the imagery component of the implementation intention was isolated from the verbal component. We suggest that implementation intention planning (relative to standard instructions) increases the likelihood that people will encode a robust associative link between the target cue and the intended action, thereby promoting reflexive triggering of the intended action on presentation of the target cue.     

Prospective memory and aging: preserved spontaneous retrieval,but impaired deactivation,in older adults

Prospective remembering is partially supported by cue-driven spontaneous retrieval processes. We investigated spontaneous retrieval processes in younger and older adults by presenting prospective memory target cues during a lexical decision task following instructions that the prospective memory task was finished. Spontaneous retrieval was inferred from slowed lexical decision responses to target cues (i.e., intention interference). When the intention was finished, younger adults efficiently deactivated their intention, but the older adults continued to retrieve their intentions. Levels of inhibitory functioning were negatively associated with intention interference in the older adult group, but not in the younger adult group. These results indicate that normal aging might not compromise spontaneous retrieval processes but that the ability to deactivate completed intentions is impaired.     

Methylphenidate reduces abnormalities of stimulus classification in adolescents with attention deficit disorder.

Forty-eight adolescents with attention deficit disorder (ADD) received placebo and methylphenidate (M = 35.21 mg/day) for 3 consecutive weeks each. ADD patients who received placebo in the first phase of treatment were compared with unmedicated normal adolescents. ADD and normal adolescents did not differ in slope of reaction time as a function of memory load in a Sternberg (1969) memory task. These results may be interpreted as reflecting normal rates of memory search in ADD. However, in comparison with normal subjects, ADD subjects made disproportionately more errors to targets and lacked faster latencies of the P3b component of event-related potentials for targets than nontargets. These findings suggest abnormalities in stimulus classification. Methylphenidate did not affect ADD patients' rates of memory search, but it did reduce misclassifications of targets at high memory loads. The drug also evoked the normal pattern of slower P3b latencies for nontargets by shortening latencies for targets. Thus the stimulant reduced ADD adolescents' abnormalities in stimulus classification.     

The Compensatory Role of Implementation Intentions for Young Adults with Low Working Memory Capacity

Many factors improve prospective memory performance both inside and outside of the laboratory, including the detailed planning of the situational cue and intended action (i.e., implementation intentions). In the current study, we obtained measures of working memory capacity and laboratory event‐based prospective memory performance in college‐aged adults. Half of our participants formed an implementation intention in the prospective memory task. Because of evidence that implementation intentions increase the encoding/retrieval efficiency of the prospective memory, it was predicted that forming an implementation intention would serve as a compensatory strategy for those with low working memory ability. Our results supported this hypothesis in that working memory capacity no longer correlated with prospective memory performance when participants employed an implementation intention encoding strategy. These findings suggest that implementation intentions may be an effective way for individuals with low working memory capacity to improve their performance in an attentionally demanding prospective memory task. Copyright © 2015 John Wiley & Sons, Ltd.     

Do novel associative word stem completion and cued recall share the same memory retrieval processes?

The aim of this study was to determine whether word stem completion for novel associations between cue and target words was mediated by automatic unconscious memory processes or effortful memory processes under conscious control. This was done by applying full and divided attention conditions at test to stem completion, cued recall, and recognition, and by administering a questionnaire that probed the memory strategies used by subjects during the completion test. Divided attention had no effect on stem completion performance, but did reduce associative cued recall. Recognition performance was weakened overall by divided attention, but the associative effect was similar under both attention conditions. This suggested that novel associative word stem completion was mediated by automatic retrieval processes. However, the results of the questionnaire indicated that only subjects who attempted to remember the words from the study phase during the completion task showed any novel associative effect. It is concluded that novel association word stem completion and cued recall share automatic retrieval processes, which nevertheless give rise to the experience of remembering.     

Age-related deficits in prospective memory: the influence of task complexity.

Younger and older subjects were asked to perform an action whenever target words occurred during a short-term memory task. The difficulty of this prospective memory task was manipulated by varying the delay preceding the occurrence of a target event and by varying the number of different target events. Age-related performance differences emerged when there were several different target events but not when there was one target event presented several times. Age-related performance differences, when they occurred, were associated with poorer retrospective memory for the target events. The results were interpreted in terms of a componential analysis of prospective memory, which assumes both similarities and differences between prospective and retrospective memory.