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.     

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.     

Implementation intentions about nonfocal event-based prospective memory tasks

Implementation intentions are detailed and systematic plans that are developed during intention formation. We compared two different implementation intentions to standard event-based prospective memory instructions using three different kinds of intentions. Two of these intentions involved nonfocal cues whereas the remaining intention was about specific, focal cues. Implementation intentions dramatically increased detection performance for the nonfocal intentions. Because the exact cues could not be specified during intention formation, we argue that cue salience and that strengthening the cue to target action association are not very viable mechanisms to explain all instances of the beneficial consequences of forming implementation intentions.     

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。     

Evidence for spontaneous retrieval of suspended but not finished prospective memories

McDaniel and Einstein (2007) argued that prospective memories can be retrieved through spontaneous retrieval processes stimulated by the presence of a target cue. To test this claim, we investigated whether presenting a prospective memory cue during a task that did not require an intention to be performed spontaneously triggered remembering of that intention. In two experiments, participants performed an image-rating task in which a prospective memory task (to press the “Q” key when a target word appeared) was embedded. Then, participants were told that their intention was finished or suspended. Finally, participants performed a lexical decision task in which each target (and a matched control) word appeared. RTs were slower to target words than to control words when the intention was suspended but not when it was finished. These results suggest that target cues associated with suspended intentions can spontaneously trigger remembering but that finished intentions are quickly deactivated.     

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.     

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.     

Investigating the encoding and retrieval of intentions with event-related potentials

Strong evidence exists in the literature that remembering to complete intentions involves executive processing subserved by the frontal lobes. Event-related potentials were measured during the encoding of actions with the intention to perform versus more neutral material about which there was no such intentionality. Event-related potentials were also measured in a two-alternative discrimination task requiring identification of the to-be-performed actions and to-be-memorized actions. The results suggest that formation and retrieval of intentions differs from encoding and retrieval of similar material committed to memory. Additionally, the results suggest that right frontal areas may play an important role in the formation of prospective actions and that intentions are kept active in memory by processing mediated by the left frontal pole.     

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.     

Evidence for a detrimental relationship between hypertension history, prospective memory, and prefrontal cortex white matter in cognitively normal older adults

Hypertension affects many older adults and is associated with impaired neural and cognitive functioning. We investigated whether a history of hypertension was associated with impairments to prospective memory, which refers to the ability to remember to perform delayed intentions, such as remembering to take medication. Thirty-two cognitively normal older adult participants with or without a history of hypertension (self-reported) performed two laboratory prospective memory tasks, one that relied more strongly on executive control (nonfocal prospective memory) and one that relied more strongly on spontaneous memory retrieval processes (focal prospective memory). We observed hypertension-related impairments for nonfocal, but not focal, prospective memory. To complement our behavioral approach, we conducted a retrospective analysis of available structural magnetic resonance imaging data. Lower white matter volume estimates in the anterior prefrontal cortex were associated with lower nonfocal prospective memory and with a history of hypertension. A history of hypertension may be associated with worsened executive control and lower prefrontal white matter volume. The translational implication is that individuals who must remember to take antihypertensive medications and to monitor their blood pressure at home may be impaired in the executive control process that helps to support these prospective memory behaviors.     

The effects of implementation intention strategies on prospective memory cue encoding

Implementation intentions, which include a structured verbal statement and mental imagery, improve prospective memory performance (i.e. remembering to execute delayed intentions). To investigate whether, and how, implementation intention strategies affect encoding processes we had participants complete a thought probe procedure immediately after forming the intention to remember to press Q when seeing fruit words. In Experiment 1, an implementation intention verbal statement (relative to control statement) significantly increased generation of high typicality exemplars (apple, banana, orange). In Experiment 2, an implementation intention imagery procedure (relative to control imagery) produced similar outcomes. In Experiment 3, combining the statement and imagery components of the implementation intention (relative to control statement and imagery) demonstrated even more potent effects (e.g. three-fold increase in fruit exemplars generated). In Experiment 4, we tested whether the control statement versus control imagery procedure differentially affected encoding, but these control procedures showed no significant differences. An interesting, unanticipated finding was that there was significantly less mind wandering in the implementation intention conditions relative to the control conditions. The current experiments provide novel information on the processes operating during intention encoding, and support the classic view that implementation intentions increase the encoding of specific retrieval cues.     

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.     

Remembering intentions: testing a new method of investigation

The paper examines some of the methodological difficulties associated with the investigation of remembering intentions in a laboratory and reports the development of a new and easily administered naturalistic task. The task requires participants to act as a narrator and read aloud a story that they are informed will help the experimenter to obtain necessary test material for another study. Remembering intentions (‘prospective memory’) is examined by presenting a plausible cover story requiring to make a correct substitution for a ‘target’ word which appears on several occasions during the story. This method seems to capture adequately the nature of prospective remembering and preclude the occurrence of ceiling, floor and practice effects in performance. By distinguishing late responses from on-time or successful prospective memory responses it also stresses the importance of taking into account the speed with which one recovers from his or her prospective memory failures. Finally, this task enables us to collect reliable and consistent quantitative measures of remembering intentions and to investigate a variety of methodologically and theoretically important problems. The results of Experiments 1a and 1b (Study 1) suggest that both the type of prospective memory task (main versus extra) and subjects' awareness of the phenomenon under investigation are important influences on performance. On the other hand, no effects of (1) a short 5-minute delay between prospective memory instruction and onset of background activity and (2) information about the frequency of target word were revealed (Study 2). The design of a popular experimental paradigm (Einstein and McDaniel, 1990) is examined in the light of these findings. Copyright © 1998 John Wiley & Sons, Ltd.     

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。     

Assessing absentmindedness: Prospective memory complaint and impairment in middle-aged adults

In two experiments, metamemorial differences between prospective and retrospective memory performance were examined. Participants in Experiment 1 were recruited through newspaper advertisements and comprised middle-aged women who experienced exceptional problems in prospective remembering. Experiment 2 involved self-reporters and nonreporters of retrospective memory problems, who were selected from a large population-based sample of middle-aged adults. In both experiments, memory performance was assessed by using a variety of tasks, including five retrospective memory tasks and three prospective memory tasks that varied in level of realism and retrieval support. In both experiments, there were selective differences in memory performance, so that participants who experienced (retrospective or prospective) memory problems showed impaired performance in prospective, but not in retrospective, memory tasks. These findings suggest that memory for future intentions provides a more sensitive task criterion than does memory for past events for assessing individual differences in self-reports of episodic memory problems. Task-specific differences in reliance on frontally mediated executive processes might underlie these differences.     

Memory for/and execution of future intentions: evidence from patients with Herpes Simplex Encephalitis

Prospective remembering was studied in a group of patients who suffered from Herpes Simplex Encephalitis (HSE). All patients showed a marked deficit in executing intentions for future actions under all the given constraints. The deficit extended to both time- and event-based intentions. The analysis of errors showed somewhat different patterns and some dissociations with evidence for selective preservation or damage to specific components involved in prospective remembering. These patients, in fact, may fail because of a difficulty in taking into account all given constraints or in activating stored intentions and in forming intentions or in remembering the content of the actions. Time- and event-based tasks seem to show different sources of errors also in the same patient.     

The dynamics of intention retrieval and coordination of action in event-based prospective memory

Event-based prospective memory requires responding to cues in the environment that are associated with a previously established intention. Some researchers believe that intentions reside in memory with an above baseline level of activation, a phenomenon called the intention superiority effect. The authors of this study predicted that intention superiority would be masked by additional cognitive processes associated with successful event-based prospective memory. These additional processes include noticing the cue, retrieving the intention, and coordinating intention execution with the ongoing activity. In 3 experiments, intention superiority was demonstrated by faster latencies to the ongoing activity on failed prospective trials and the existence of the additional processes was demonstrated by slower latencies on successful trials. This study demonstrates the importance of investigating the microstructure of the cognitive components involved with processing and responding to an event-based prospective memory cue.     

The effects of familiar size on judgments of size and distance: An interaction of viewing attitude with spatial cues

Two hypotheses about the effects of familiar size on judgments of size and distance, the cue-conflict hypothesis and the viewing-attitude hypothesis, were examined. In Experiment 1, observers estimated the size and distance of familiar targets with apparent or assumptive instructions under three different spatial cue conditions. In Experiment 2, observers performed tasks similar to those of Experiment 1 with no specific instructions. The main results were: (1) Assumptive instructions facilitate the effects of familiar size in both size and distance judgments, but reducing spatial cues does not, and (2) viewing attitude changes from the apparent to the assumptive when available spatial cues are reduced. Thus, it was concluded that the viewing-attitude hypothesis gives a better account of the effects of familiar size, but that the cue-conflict hypothesis cannot be abandoned, because the number of conflicting cues contributes to the formation of viewing attitude.     

Prospective Memory and Divided Attention

In three experiments, we manipulated the processing demands of a concurrent task to test the hypothesis that an event-based prospective memory task satisfies a criterion of automaticity proposed by Hasher and Zacks (1979). As in the previous studies, a prospective memory task (pressing a key whenever a target word was presented) was embedded within a short-term memory task (remembering seven words). In addition, participants performed a concurrent memory task which varied in difficulty. Participants repeated either 0 to 6 randomly generated digits or a single word. In all three experiments, short-term memory performance was influenced by the concurrent memory load. Prospective performance, in contrast, was not affected by the memory load even though an attempt was made to increase the difficulty of the prospective task by manipulating the specificity of the target instructions (Experiment 2) and the number of target words (Experiments 2 and 3). The results are discussed within the framework of automatic processing.