The effects of working memory resource availability on prospective memory: a formal modeling approach

The PAM theory of event-based prospective memory (Smith, 2003; Smith & Bayen, 2004a) proposes that successful prospective memory performance demands upon the interaction of preparatory attentional processes and retrospective memory processes. The two experiments in the current study represent the first application of a formal model to investigate the sensitivity of these underlying processes to variations in working memory resource availability. Multinomial modeling of data from prospective-memory tasks showed that working memory span influenced preparatory attentional processes and retrospective-memory processes.     

Remembered duration: working memory and the reproduction of intervals

On the basis of attention allocation models of time estimation, the role of working memory in prospective duration reproduction is explored. In four experiments, adult participants performed a counting task (duration, 400 sec) that allowed coordinative and sequential demands on working memory to be varied. After completing the counting task, the participants reproduced the time that they had worked on this task It emerged that (1) increased coordinative demands on working memory (but not increased sequential demands) reduced the accuracy of prospective duration reproduction (Experiments 1 and 2), (2) presenting context information during the reproduction phase enhanced the accuracy of the reproduced duration (Experiment 3), and (3) individual differences in coordinative working memory capacity affected duration reproduction in the same direction as the experimental manipulation of coordinative task demands (Experiment 4). The results suggest that attention allocation models of time estimation may benefit from taking a more differentiated view of the types of attentional demands that affect temporal cognition.     

Beliefs about Memory as a Mediator of Relations between Metacognitive Beliefs and Actual Memory Performance

The goal of the present study was to investigate relationships between personal beliefs about memory, metacognitive beliefs, and actual memory performance. One hundred thirty-seven participants' (aged 20 to 60 years) metacognitive beliefs were measured using the Metacognition Questionnaire (MCQ-30), memory beliefs were measured using the Personal Beliefs about Memory Instrument (PBMI), and an episodic memory task was used to measure actual memory performance, memory predictions, and postdictions. Younger adults had lower scores on the positive beliefs subfactor of the MCQ-30, higher scores on retrospective change and control subfactors of the PBMI, and outperformed middle-aged adults on recall and recall postdiction. Path analysis showed that individuals' beliefs about memory mediate the relationship between metacognitive beliefs and actual memory performance. Specifically, low lack of confidence (or less worry) in one's own memory and attentional capabilities was related to higher memory performance and positive personal beliefs regarding specific memory ability mediated relationship.     

Prospective memory in the rat

The content of prospective memory is comprised of representations of an action to perform in the future. When people form prospective memories, they temporarily put the memory representation in an inactive state while engaging in other activities, and then activate the representation in the future. Ultimately, successful activation of the memory representation yields an action at an appropriate, but temporally distant, time. A hallmark of prospective memory is that activation of the memory representation has a deleterious effect on current ongoing activity. Recent evidence suggests that scrub jays and non-human primates, but not other species, are capable of future planning. We hypothesized that prospective memory produces a selective deficit in performance at the time when rats access a memory representation but not when the memory representation is inactive. Rats were trained in a temporal bisection task (90 min/day). Immediately after the bisection task, half of the rats received an 8-g meal (meal group) and the other rats received no additional food (no-meal group). Sensitivity to time in the bisection task was reduced as the 90-min interval elapsed for the meal group but not for the no-meal group. This time-based prospective-memory effect was not based on response competition, an attentional limit, anticipatory contrast, or fatigue. Our results suggest that rats form prospective memories, which produces a negative side effect on ongoing activity.     

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.     

Optimistic metacognitive judgments predict poor performance in relatively complex visual tasks

In some cases, people overestimate how much they can see. This can produce a metacognitive blind spot that may lead participants to devote fewer cognitive resources than a visual task demands. However, little research has tested whether individuals who are particularly optimistic about their visual capabilities are susceptible to poor visual performance. We tested whether optimistic metacognitive judgments would predict poor performance in a visual task, especially when it placed a large attentional load on the participant, and when it required balancing between multiple sources of information. We tested participants in a simplified battle command simulation in which they were asked to detect visual changes. Participants who predicted spatially expansive visual attention performance performed more poorly in the change detection task when the task required tracking larger numbers of aircraft, and when it included a secondary change-list display.     

Retrieval experience in prospective memory: strategic monitoring and spontaneous retrieval

According to the multi-process model of prospective memory (McDaniel & Einstein, 2000), performance in a prospective memory task may be due to spontaneous retrieval processes or due to strategic monitoring. Spontaneous retrieval is typically accompanied by a pop up experience and strategic monitoring by a search experience. In this study we report two experiments with young adults in which we systematically investigated whether retrieval experience differed across experimental conditions. In Experiment 1 some prospective memory targets were preceded by associated primes. We expected that presenting primes would enhance performance by an automatic activation of the intention and hence lead to an increase in pop up experiences. In Experiment 2 half of the participants received instructions containing information about the specific context in which the prospective memory task would occur, whereas the other half of the participants received no such information. We expected that specific context instructions would enhance performance by legitimate anticipation of the prospective memory task and hence would lead to an increase in search experiences. The results confirmed these expectations. They indicate that the assessment of retrieval experience can provide valuable insights into the processes underlying prospective memory performance. They also suggest that retrieval experience can vary systematically across experimental situations as predicted by the multi-process model.     

A characterization of individual differences in prospective memory monitoring using the Complex Ongoing Serial Task

Prospective memory--remembering to retrieve and execute future goals--is essential to daily life. Prospective remembering is often achieved through effortful monitoring; however, potential individual differences in monitoring patterns have not been characterized. We propose 3 candidate models to characterize the individual differences present in prospective memory monitoring: attentional focus, secondary memory retrieval, and information thresholding. Two experiments using a novel paradigm, the Complex Ongoing Serial Task (COST), investigated the resource allocation patterns underlying individual differences in monitoring. Individuals exhibited differential resource allocation patterns, and the differences remained relatively stable across experimental sessions. Resource allocation patterns associated with information thresholding (high prospective memory, preserved ongoing task performance) and attentional focus (high prospective memory, inefficient ongoing task performance) were superior to secondary memory retrieval (low prospective memory, very inefficient ongoing task performance). Importantly, personality (openness, prevention focus) and cognitive (primary, working, and secondary memory) individual differences influenced monitoring patterns. This research represents the first explicit attempt to elucidate individual differences in prospective memory monitoring patterns.     

The interplay of intention maintenance and cue monitoring in younger and older adults’ prospective memory

The retention phase of a prospective memory (PM) task poses different challenges, including demands to store or maintain an intended action and to realize the right moment for action execution. The interplay of these processes in younger and older adults has not been explored so far. In this study, the authors examined the impact of maintenance load and task focality on PM in 84 younger and in 83 older adults. Results indicated that PM performance and ongoing task response times were strongly affected by maintenance load and age. However, a focality effect only emerged when maintenance load was low but not when attentional resources were deployed for maintaining a more demanding intention. These findings suggest that maintenance and monitoring requirements compete for similar attentional resources. Furthermore, maintenance load may affect postretrieval processes through its impact on working-memory resources, which can restrain the typical advantage of focal over nonfocal PM tasks.     

Prospective memory and pediatric traumatic brain injury: effects of cognitive demand.

This study investigated the effects of pediatric traumatic brain injury (TBI) on prospective memory. Fourteen children and 14 adolescents with TBI were compared with 25 and 23 noninjured children and adolescents, respectively. Based on a prefrontal model, the cognitive demand on the ongoing component of a prospective-memory task was manipulated. Overall, those with TBI had poorer prospective-memory performance than their noninjured peers. Performance was worse in a high cognitive-demand condition than a low, and younger children performed worse than adolescents. Decreases in performance from the low- to high-demand conditions were not significantly different between the two children's groups but were between the two adolescents' groups. Furthermore, the age and injury effects were reflected in the performances on executive function tests: the Self-ordered Pointing Task (SOPT), and the Stroop Color Word Interference Test. The Tower of London (TOL), which did not produce age or injury effects, was nevertheless found to be an important predictor of performance on the high-demand task in those with TBI. Although previous research has demonstrated impaired prospective memory performance in children with TBI, this study attempted to explain why this might occur, specifically that the prefrontal regions might be implicated.     

Prospective memory in young and older adults: the effects of ongoing-task load

Prospective memory involves remembering to perform intended actions in the future. Previous work with the multinomial model of event-based prospective memory indicated that adult age-related differences in prospective-memory performance were due to the prospective (not the retrospective) component of the task (Smith & Bayen, 2006 , Journal of Experimental Psychology: Learning, Memory, and Cognition, 32, 623). However, ongoing-task performance was also lower in older adults in that study. In the current study with young and older adults, the difficulty of the ongoing task was manipulated by varying the number of colors per trial to create easier and harder versions of the ongoing task for each age group. The easier version included 2 colors per trial for older adults and 4 colors for young adults. The harder version included 4 colors for older adults and 6 colors for young adults. By adjusting the ongoing-task difficulty, older adults were able to perform the ongoing task as well or better than the young adults. Analyses with the multinomial model revealed that making the ongoing task easier for older adults (or more difficult for young adults) did not eliminate age-related differences in prospective-memory performance and the underlying prospective component.     

Negative prospective memory: Remembering not to perform an action

Sometimes it is important to remember not to perform an action, such as remembering to stop taking seasonal allergy medicine when it is no longer needed. Mistakes in accomplishing this goal can involve prospective memory commission errors when individuals mistakenly perform a prospective response. In two experiments, we investigated the role of attentional resources in preventing prospective memory errors to cues that had been associated with a habitual prospective response. In Phase 1 of our experiments, participants performed a prospective memory task during which they either routinely responded to prospective memory cues or responded to these cues one time only. On a subsequent prospective memory task, the participants who had routinely responded to prospective memory cues were vulnerable to commission errors when their attentional resources were taxed. By contrast, dividing attention did not increase commission errors to cues that had not been routinely performed on an earlier task. These data indicate that attentional resources are needed to withhold making habitual prospective memory responses, and they suggest that inhibitory failures are a cause of these prospective memory errors. Finally, we suggest a broader definition of prospective memory that includes remembering to withhold performing actions.     

Importance effects on performance in event-based prospective memory tasks

In the present study we manipulated the importance of performing two event-based prospective memory tasks. In Experiment 1, the event-based task was assumed to rely on relatively automatic processes, whereas in Experiment 2 the event-based task was assumed to rely on a more demanding monitoring process. In contrast to the first experiment, the second experiment showed that importance had a positive effect on prospective memory performance. In addition, the occurrence of an importance effect on prospective memory performance seemed to be mainly due to the features of the prospective memory task itself, and not to the characteristics of the ongoing tasks that only influenced the size of the importance effect. The results suggest that importance instructions may improve prospective memory if the prospective task requires the strategic allocation of attentional monitoring resources.     

Prospective Memory and Pediatric Traumatic Brain Injury: Effects of Cognitive Demand

This study investigated the effects of pediatric traumatic brain injury (TBI) on prospective memory. Fourteen children and 14 adolescents with TBI were compared with 25 and 23 noninjured children and adolescents, respectively. Based on a prefrontal model, the cognitive demand on the ongoing component of a prospective-memory task was manipulated. Overall, those with TBI had poorer prospective-memory performance than their noninjured peers. Performance was worse in a high cognitive-demand condition than a low, and younger children performed worse than adolescents. Decreases in performance from the low- to high-demand conditions were not significantly different between the two children's groups but were between the two adolescents' groups. Furthermore, the age and injury effects were reflected in the performances on executive function tests: the Self-ordered Pointing Task (SOPT), and the Stroop Color Word Interference Test. The Tower of London (TOL), which did not produce age or injury effects, was nevertheless found to be an important predictor of performance on the high-demand task in those with TBI. Although previous research has demonstrated impaired prospective memory performance in children with TBI, this study attempted to explain why this might occur, specifically that the prefrontal regions might be implicated.     

Importance effects on performance in event‐based prospective memory tasks

In the present study we manipulated the importance of performing two event‐based prospective memory tasks. In Experiment 1, the event‐based task was assumed to rely on relatively automatic processes, whereas in Experiment 2 the event‐based task was assumed to rely on a more demanding monitoring process. In contrast to the first experiment, the second experiment showed that importance had a positive effect on prospective memory performance. In addition, the occurrence of an importance effect on prospective memory performance seemed to be mainly due to the features of the prospective memory task itself, and not to the characteristics of the ongoing tasks that only influenced the size of the importance effect. The results suggest that importance instructions may improve prospective memory if the prospective task requires the strategic allocation of attentional monitoring resources.     

Age-related changes in event-related prospective memory performance: a comparison of four prospective memory tasks

The primary purpose of the study was to identify event-based prospective-memory tasks that provide sensitive and reliable tools for assessing effects of normal aging in prospective-memory performance. Four prospective-memory tasks were selected from the literature or were newly developed, with the tasks differing on various dimensions that, for theoretical reasons or based on previous evidence, might determine task sensitivity to age effects on prospective-memory performance: perceptual saliency of prospective target events, frequency of occurrence of prospective target events, complexity of prospective-memory instructions, and provision of feedback after prospective-memory errors. Two of the four tasks yielded large and robust age effects on prospective-memory performance. Correlational analyses suggested that these age effects on prospective-memory performance were mediated, at least in part, by a reduced ability of older adults to maintain prospective intentions in a highly activated state and not by age effects on basic mental speed alone.     

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。     

Retrospective and prospective metacognitive judgments in rhesus macaques (Macaca mulatta)

A growing body of research suggests that some non-human animals are capable of making accurate metacognitive judgments. In previous studies, non-human animals have made either retrospective or prospective judgments (about how they did on a test or how they will do on a test, respectively). These two types of judgments are dissociable in humans. The current study tested the abilities of two rhesus macaque monkeys to make both retrospective and prospective judgments about their performance on the same memory task. Both monkeys had been trained previously to make retrospective confidence judgments. Both monkeys successfully demonstrated transfer of retrospective metacognitive judgments to the new memory task. Furthermore, both monkeys transferred their retrospective judgments to the prospective task (one, immediately, and one, following the elimination of a response bias). This study is the first to demonstrate both retrospective and prospective monitoring abilities in the same monkeys and on the same task, suggesting a greater level of flexibility in animals’ metacognitive monitoring abilities than has been reported previously.     

Age Differences in Multiple Outcome Measures of Time-Based Prospective Memory

ABSTRACT

This study examined time-based prospective memory performance in relation to age, monitoring strategy, response accuracy, and dual-task demands. Young, middle-aged and older adults (N?=?115) completed a prospective memory task, in which they indicated the passing of time every 5 min while listening to a short story (low task demands) or completing a series of cognitive tasks (high task demands). Young and older adults showed similar patterns of monitoring behavior, with low rates of clock checking during the early phase of each 5-min interval, followed by linearly accelerating monitoring functions. However, to obtain the same level of prospective memory performance older adults needed more frequent clock checks than young adults. Furthermore, older adults' compensatory monitoring strategy was associated with an additional cost in primary task performance. Finally, increased primary task demands shifted age differences in prospective memory from monitoring frequency to response accuracy. These findings suggest that goal-directed behavior requires efficient task coordination and resource allocation, and that age-related differences in time-based prospective memory should be evaluated by using multiple outcome measures.     

Distractor filtering in media multitaskers

A growing amount of modern media is consumed simultaneously, a phenomenon known as 'media multitasking'. Individuals who regularly engage in this activity, heavy media multitaskers (HMMs), are more affected by irrelevant information that can intrude into a primary task than are light media multitaskers (LMMs--Ophir et al, 2009 Proceedings of the National Academy of Sciences of the USA 106 15583). However, the locus of this deficit is unknown, as previous research is consistent with both memory and attentional explanations. Here, we isolated attentional processes by employing a singleton distractor task with low working-memory demands. In this task, LMMs used top-down information to improve their performance, yet HMMs did not. This difference in performance in an established attentional capture task argues for the presence of attentional differences in HMMs and is consistent with the idea that HMMs maintain a wider attentional scope than LMMs, even when instructed otherwise.