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.     

The effects of age, enactment, and cue-action relatedness on memory for intentions in the Virtual Week task

ABSTRACT The current study investigated the influence of encoding modality and cue-action relatedness on prospective memory (PM) performance in young and older adults using a modified version of the Virtual Week task. Participants encoded regular and irregular intentions either verbally or by physically performing the action during encoding. For half of the intentions there was a close semantic relation between the retrieval cue and the intended action, while for the remaining intentions the cue and action were semantically unrelated. For irregular tasks, both age groups showed superior PM for related intentions compared to unrelated intentions in both encoding conditions. While older adults retrieved fewer irregular intentions than young adults after verbal encoding, there was no age difference following enactment. Possible mechanisms of enactment and relatedness effects are discussed in the context of current theories of event-based PM.     

The effects of age,enactment, and cue-action relatedness on memory for intentions in the Virtual Week task

ABSTRACT

The current study investigated the influence of encoding modality and cue-action relatedness on prospective memory (PM) performance in young and older adults using a modified version of the Virtual Week task. Participants encoded regular and irregular intentions either verbally or by physically performing the action during encoding. For half of the intentions there was a close semantic relation between the retrieval cue and the intended action, while for the remaining intentions the cue and action were semantically unrelated. For irregular tasks, both age groups showed superior PM for related intentions compared to unrelated intentions in both encoding conditions. While older adults retrieved fewer irregular intentions than young adults after verbal encoding, there was no age difference following enactment. Possible mechanisms of enactment and relatedness effects are discussed in the context of current theories of event-based PM.     

Differences in target monitoring in a prospective memory task

The goal of the present study was to examine individual differences in the degree to which controlled attention is allocated towards a prospective memory (PM) task. Using a PM task that should require high levels of controlled attention in a sample of 138 young, middle-aged, and older adults, two subgroups of participants could be identified, i.e., participants who clearly demonstrated evidence for monitoring and those for whom no clear evidence for monitoring was revealed. A control group (n=95) was tested to control for practice effects in the ongoing task. Differences between subgroups were examined in terms of age, PM accuracy, baseline ongoing task performance, and general negative mood. Nonmonitorers and monitorers differed in age (more older adults being nonmonitorers), ongoing task accuracy (a nonsignificant trend was observed here), PM task accuracy (both young and middle-aged/older monitorers were more accurate than nonmonitorers), and the number of reported depressive symptoms (nonmonitorers > monitorers). Moreover, results showed that even in nonmonitorers PM accuracy was above floor level, indicating that noticing and reacting to some of PM cues is possible without strongly investing in resource demanding monitoring processes.     

Growth curve models in retrospective memory and prospective memory: the relationship between prediction and performance with task experience

Older adults commonly experience declines in episodic memory that affect their daily lives. The aim was to examine whether the acquired metacognitive awareness that comes with task experience, indexed by meta-retrospective memory (meta-RM)/meta-prospective memory (meta-PM), influences how older adults predict performance on later trials. Participants were 178 community-dwelling older adults. RM performance and predictions were measured using a multi-trial word-list learning task. Predictions and performance for PM were measured using a PM paradigm. Change in RM/PM performance and predictions over the trials/blocks were modelled using latent growth curve analyses. For RM, both predictions and performance increased with task experience. However, for PM, neither performance nor predictions changed with task experience. Hierarchical multiple regressions revealed that metacognitive awareness acquired during the RM and PM tasks influenced how older adults’ modified their predictions of subsequent task performance. Findings are consistent with [Toglia and Kirk’s (2000). Understanding awareness deficits following brain injury. NeuroRehabilitation, 15(1), 57–70] hypothesis that individuals compare ongoing performance to expectations based on metacognitive knowledge, such that a discrepancy between actual and expected performance may influence emergent awareness.     

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

ABSTRACT

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 Smith, R. E. and Bayen, U. J. 2006. The source of age differences in event-based prospective memory: A multinomial modeling approach. Journal of Experimental Psychology: Learning, Memory, and Cognition, 32: 623–635. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 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.     

Age, Focal Processing, and Monitoring in Event-Based Prospective Memory

While there is some consensus that prospective memory (PM) declines with age, the reasons for differences in performance across age groups are not fully understood. This experiment examines two factors that are likely to affect the magnitude of observed age group differences: type of PM task and whether participants monitor the task environment for the opportunity to complete the PM task. Younger and older adults were engaged in an ongoing test of short-term memory and were asked to perform one of two different event-based PM tasks. Younger adults performed better than older adults on both focal and nonfocal PM tasks. In addition, younger adults were able to perform both types of tasks equally well, but older adults were more successful on the focal task than on the nonfocal task. Age group differences in self-reported PM monitoring were also evident and were related to performance. These findings and their implications for current theoretical conceptions of PM aging are discussed.     

Effects of context expectation on prospective memory performance among older and younger adults

This experiment examined the impact of context expectation on prospective memory (PM) performance among older and younger adults. Participants responded to PM target words embedded in an ongoing lexical decision task (LDT). Older and younger adults performed similarly on the PM task. Regardless of age, PM was significantly better for participants in the correct context expectation condition and significantly worse in the incorrect context expectation condition relative to participants who held no expectations about the context in which targets would appear. Participants’ LDT response latencies were used to assess cost of the PM task to the ongoing task. Latencies were discernibly longer in the LDT block where the PM targets were expected compared to the block where they were not expected. The findings provide new information about how context can be used to support PM aging and suggest that contextual information can be equally beneficial for older and younger adults.     

Influences on the efficiency of prospective memory in younger and older adults.

The influence of 4 factors on age-related declines in prospective memory (PM) was considered in 2 experiments. The results of the experiments reveal that age-related differences in PM were not moderated by the degree of match between the nature of processing required in the ongoing activity and the defining features of the PM cue. Age-related differences in the accuracy of PM responses were primarily attributable to an increase in the number of omission errors committed by older adults. Age-related differences in PM were somewhat independent of the ability to recall the PM cues and intentions following task performance and were mediated by the cognitive resources of processing speed, inhibitory control, and working memory.     

Task coordination and aging: explorations of executive control processes in the task switching paradigm.

A number of models of cognitive aging suggest that older adults exhibit disproportionate performance decrements on tasks which require executive control processes. In a series of three studies we examined age-related differences in executive control processes and more specifically in the executive control processes which underlie performance in the task switching paradigm. Young and old adults were presented with rows of digits and were required to indicate whether the number of digits (element number task) or the value of the digits (digit value task) were greater than or less than five. Switch costs were assessed by subtracting the reaction times obtained on non-switch trials from trials following a task switch. Several theoretically interesting results were obtained. First, large age-related differences in switch costs were found early in practice. Second, and most surprising, after relatively modest amounts of practice old and young adults switch costs were equivalent. Older adults showed large practice effects on switch trials. Third, age-equivalent switch costs were maintained across a two month retention period. Finally, the main constraint on whether age equivalence was observed in task switching performance was memory load. Older adults were unable to capitalize on practice under high memory loads. These data are discussed in terms of their implications for both general and process specific cognitive aging models.     

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.     

Prospective memory performance across adolescence

In the present study, the authors explored age differences in event-based prospective memory (PM) across adolescence. The tasks consisted of an ongoing task (OT; i.e., personality questionnaire items, math problems) and an embedded prospective task that required participants to remember to make a special response whenever they encountered a PM cue (i.e., a negative word in the OT). The 341 participants (aged 13-22 years) revealed a significant main effect of age, which indicated better PM performance of young adults compared with teenagers. Moreover, when emphasizing the OT versus the PM task, teenagers' PM profited from PM emphasis more than did young adults' PM. The authors discuss the data in the context of limited executive capacity as a factor influencing cognitive development across adolescence.     

Future thinking instructions improve prospective memory performance in adolescents

Studies on prospective memory (PM) development in adolescents point to age-related increases through to adulthood. The goal of the present study was to examine whether instructing adolescents to engage in an episodic prospection of themselves executing future actions (i.e., future thinking) when forming an intention would improve their PM performance and reduce age-related differences. Further, we set out to explore whether future thinking instructions result in stronger memory traces and/or stronger cue–context associations by evaluating retrospective memory for the PM cues after task completion and monitoring costs during PM task processing. Adolescents and young adults were allocated to either the future thinking, repeated-encoding or standard condition. As expected, adolescents had fewer correct PM responses than young adults. Across age groups, PM performance in the standard condition was lower than in the other encoding conditions. Importantly, the results indicate a significant interaction of age by encoding condition. While adolescents benefited most from future thinking instructions, young adults performed best in the repeated-encoding condition. The results also indicate that the beneficial effects of future thinking may result from deeper intention-encoding through the simulation of future task performance.     

Emotional target cues eliminate age differences in prospective memory

Cue saliency is known to influence prospective memory performance, whereby perceptually or conceptually distinct cues facilitate remembering and attenuate adult age-related deficits. The present study investigated whether similar benefits for older adults are also seen for emotional valence. A total of 41 older and 41 younger adults performed a prospective memory task in which the emotional valence of the prospective memory cues was manipulated. Emotionally valenced cues increased prospective memory performance across both groups. Age deficits were only observed when neutral (but not positive or negative) prospective cues were presented. Findings are consistent with predictions that salient cues facilitate participants' prospective memory performance and reduce age-related differences, while extending the concept of saliency to include emotional valence.     

Effects of age and type of picture on visuospatial working memory assessed with a computerized jigsaw-puzzle task

We investigated the effect of age and color in a computerized version of the jigsaw-puzzle task. In Experiment 1, young and older adults were presented with puzzles in color and black-and-white line drawings, varying in difficulty from 4 to 9 pieces. Older adults performed the task better with the black-and-white stimuli and younger adults performed better with the color ones. In Experiment 2, new older and young adults identified the same fragmented pictures as fast and accurately as possible. The older group identified the black-and-white stimuli faster than those presented in color, while the younger adults identified both similarly. In Experiment 3A, new older and young groups performed the puzzle task with the same color pictures and their monochrome versions. In Experiment 3B, participants performed a speeded identification task with the two sets. The findings of these experiments showed that older adults have a memory not a perceptual difficulty.     

The effects of aging and dual task demands on language production

A digital pursuit rotor task was used to measure dual task costs of language production by young and older adults. After training on the pursuit rotor, participants were asked to track the moving target while providing a language sample. When simultaneously engaged, young adults experienced greater dual task costs to tracking, fluency, and grammatical complexity than older adults. Older adults were able to preserve their tracking performance by speaking more slowly. Individual differences in working memory, processing speed, and Stroop interference affected vulnerability to dual task costs. These results demonstrate the utility of using a digital pursuit rotor to study the effects of aging and dual task demands on language production and confirm prior findings that young and older adults use different strategies to accommodate to dual task demands.     

The age prospective memory paradox: young adults may not give their best outside of the lab

Previous research has identified the age prospective memory paradox of age-related declines in laboratory settings in contrast to age benefits in naturalistic settings. Various factors are assumed to account for this paradox, yet empirical evidence on this issue is scarce. In 2 experiments, the present study examined the effect of task setting in a laboratory task and the effect of motivation in a naturalistic task on prospective memory performance in young and older adults. For the laboratory task (Experiment 1, n = 40), we used a board game to simulate a week of daily activities and varied features of the prospective memory task (e.g., task regularity). For the naturalistic task (Experiment 2, n = 80), we instructed participants to try to remember to contact the experimenter repeatedly over the course of 1 week. Results from the laboratory prospective memory tasks indicated significant age-related decline for irregular tasks (p = .006) but not for regular and focal tasks. In addition, in the naturalistic task, the age benefit was eliminated when young adults were motivated by incentives (F < 1). In conclusion, the present results indicate that the variability of age differences in laboratory prospective memory tasks may be due in part to differences in the features of the prospective memory task. Furthermore, increases in motivation to perform the prospective task seem to help remedy prospective memory deficits in young adults in the naturalistic setting.     

Prospective memory, emotional valence and ageing

Emotional factors have been found to be an important influence on memory. The current study investigated the influence of emotional salience and age on a laboratory measure of prospective memory (PM); Virtual Week. Thirty young and 30 old adults completed Virtual Week, in which the emotional salience of the tasks at encoding was manipulated to be positive, negative or neutral in content. For event-based, but not time-based tasks, positivity enhancement in both age groups was seen, with a greater number of positive PM tasks being performed relative to neutral tasks. There was no negativity enhancement effect. Older adults showed generally poorer levels of PM, but they also demonstrated greater beneficial effects of positive valence compared to young. These effects of emotion on PM accuracy do not appear to reflect the retrospective component of the task as a different pattern of emotion effects was seen on the recall of PM content. Results indicate that older adults' difficulties in prospective remembering can be reduced where the tasks to be remembered are positive.     

Prospective memory and aging: The effects of working memory and prospective memory task load

Abstract

A person's level of engagement in other actions may influence whether a prospective action is correctly performed. This study used a computerized prospective memory task in which participants remembered to perform an action when a specified background pattern appeared while they simultaneously performed a verbal working memory task. Amount of engagement in the working memory task was manipulated by increasing the number of words to be recalled. Prospective memory load was manipulated by varying the number of prospective targets. Older adults performed more poorly than younger adults on the prospective memory task under higher working memory load and also higher prospective load. Participants with lower working memory load performed better on the prospective task, regardless of age. There were no significant age differences in the absolute accuracy of performance postdictions (post experiment performance awareness). Age differences were also found with a second prospective memory task in which participants were told to write the day of the week (DOW) on the top of answer sheets for tasks performed later in the experiment. No significant correlations were observed between the two prospective memory tasks for either age group.     

Age-related changes in neural mechanisms of prospective memory

The capability to remember and execute intentions in the future – termed prospective memory (PM) – may be of special significance for older adults to enable successful completion of important activities of daily living. Despite the importance of this cognitive function, mixed findings have been obtained regarding age-related decline in PM, and, currently, there is limited understanding of potential contributing mechanisms. In the current study, older (N=41) and younger adults (N=47) underwent task-functional MRI during performance of PM conditions that encouraged either spontaneous retrieval (Focal) or sustained attentional monitoring (Non-focal) to detect PM targets. Older adults exhibited a reduction in PM-related sustained activity within the anterior prefrontal cortex (aPFC) and associated dorsal frontoparietal cognitive control network, due to an increase in non-specific sustained activation in (no-PM) control blocks (i.e., an age-related compensatory shift). Transient PM-trial specific activity was observed in both age groups within a ventral parietal memory network that included the precuneus. However, within a left posterior inferior parietal node of this network, transient PM-related activity was selectively reduced in older adults during the non-focal condition. These age differences in sustained and transient brain activity statistically mediated age-related declines in PM performance, and were potentially linked via age-related changes in functional connectivity between the aPFC and precuneus. Together, they support an account consistent with the Dual Mechanisms of Control framework, in which age-related PM declines are due to neural mechanisms that support proactive cognitive control processes, such as sustained attentional monitoring, while leaving reactive control mechanisms relatively spared.