Michael K. Scullin

Control of Cost in Prospective Memory: Evidence for Spontaneous Retrieval Processes.

To examine the processes that support prospective remembering, previous research has often examined whether the presence of a prospective memory task slows overall responding on an ongoing task. Although slowed task performance suggests that monitoring is present, this method does not clearly establish whether monitoring is functionally related to prospective memory performance. According to the multiprocess theory (McDaniel & Einstein, 2000), monitoring should be necessary to prospective memory performance with nonfocal cues but not with focal cues. To test this hypothesis, we varied monitoring by presenting items that were related (or unrelated) to the prospective memory task proximal to target events. Notably, whereas monitoring proximal to target events led to a large increase in nonfocal prospective memory performance, focal prospective remembering was high in the absence of monitoring, and monitoring in this condition provided no additional benefits. These results suggest that when monitoring is absent, spontaneous retrieval processes can support focal prospective remembering. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Focal/Nonfocal Cue Effects in Prospective Memory: Monitoring Difficulty or Different Retrieval Processes?

We investigated whether focal/nonfocal effects (e.g., Einstein et al., 2005) in prospective memory (PM) are explained by cue differences in monitoring difficulty. In Experiment 1, we show that syllable cues (used in Einstein et al., 2005) are more difficult to monitor for than are word cues; however, initial-letter cues (in words) are similar in monitoring difficulty to word cues (Experiments 2a and 2b). Accordingly, in Experiments 3 and 4, we designated either an initial letter or a particular word as a PM cue in the context of a lexical decision task, a task that presumably directs attention to focal processing of words but not initial letters. We found that the nonfocal condition was more likely than the focal condition to produce costs to the lexical decision task (task interference). Furthermore, when task interference was minimal or absent, focal PM performance remained relatively high, whereas nonfocal PM performance was near floor (Experiment 4). Collectively, these results suggest that qualitatively different retrieval processes can support prospective remembering for focal versus nonfocal cues.

Sleep, Cognition, and Normal Aging Integrating a Half Century of Multidisciplinary Research

Sleep is implicated in cognitive functioning in young adults. With increasing age, there are substantial changes to sleep quantity and quality, including changes to slow-wave sleep, spindle density, and sleep continuity/fragmentation. A provocative question for the field of cognitive aging is whether such changes in sleep physiology affect cognition (e.g., memory consolidation). We review nearly a half century of research across seven diverse correlational and experimental domains that historically have had little crosstalk. Broadly speaking, sleep and cognitive functions are often related in advancing age, though the prevalence of null effects in healthy older adults (including correlations in the unexpected, negative direction) indicates that age may be an effect modifier of these associations. We interpret the literature as suggesting that maintaining good sleep quality, at least in young adulthood and middle age, promotes better cognitive functioning and serves to protect against age-related cognitive declines.

Implementation intention encoding does not automatize prospective memory responding

An implementation intention encoding, one that specifies the concrete situation that is appropriate for initiating an intended action and links that situational cue to the intended action, has been shown to improve prospective memory. One proposed mechanism is that implementation intentions create automatized prospective remembering. This view anticipates that implementation intentions should prevent prospective memory decline in highly cognitively demanding situations. Contrary to this expectation, although implementation intention encoding enhanced prospective memory (Experiments 1 and 2), implementation-intention encoding did not buffer against significant prospective memory decline in high-cognitive-demand conditions (Experiments 1–3), and in Experiment 3, implementation intention encoding produced lower levels of prospective memory performance than did behavioral practice in the high-cognitive-demand situation. We suggest that although implementation intentions may stimulate a strong associative encoding (between an anticipated environmental cue and an intended action), that encoding does not support a completely automatized prospective memory response.

Sleep, Memory, and Aging: The Link Between Slow-Wave Sleep and Episodic Memory Changes From Younger to Older Adults

In younger adults, recently learned episodic memories are reactivated and consolidated during slow-wave sleep (SWS). It is interesting that SWS declines across the life span, but little research has examined whether sleep-dependent memory consolidation occurs in older adults. In this study, younger adults and healthy older adults encoded word pairs in the morning or evening and then returned following a sleep or no-sleep interval. Sleep-stage scoring was obtained by using a home sleep-stage monitoring system. In the younger adult group, there was a positive correlation between word retention and amount of SWS during the retention interval. In contrast, the older adults demonstrated no significant positive correlations but one significant negative correlation between memory and SWS. These findings suggest that the link between episodic memory and SWS that is typically observed in younger adults may be weakened or otherwise changed in the healthy older adult population.

The Dynamic Multiprocess Framework: Evidence from prospective memory with contextual variability

The ability to remember to execute delayed intentions is referred to as prospective memory. Previous theoretical and empirical work has focused on isolating whether a particular prospective memory task is supported either by effortful monitoring processes or by cue-driven spontaneous processes. In the present work, we advance the Dynamic Multiprocess Framework, which contends that both monitoring and spontaneous retrieval may be utilized dynamically to support prospective remembering. To capture the dynamic interplay between monitoring and spontaneous retrieval, we had participants perform many ongoing tasks and told them that their prospective memory cue may occur in any context. Following either a 20-min or a 12-h retention interval, the prospective memory cues were presented infrequently across three separate ongoing tasks. The monitoring patterns (measured as ongoing task cost relative to a between-subjects control condition) were consistent and robust across the three contexts. There was no evidence for monitoring prior to the initial prospective memory cue; however, individuals who successfully spontaneously retrieved the prospective memory intention, thereby realizing that prospective memory cues could be expected within that context, subsequently monitored. These data support the Dynamic Multiprocess Framework, which contends that individuals will engage monitoring when prospective memory cues are expected, disengage monitoring when cues are not expected, and that when monitoring is disengaged, a probabilistic spontaneous retrieval mechanism can support prospective remembering.

Remembering to Execute a Goal Sleep on It

Remembering to execute deferred goals (prospective memory) is a ubiquitous memory challenge, and one that is often not successfully accomplished. Could sleeping after goal encoding promote later execution? We evaluated this possibility by instructing participants to execute a prospective memory goal after a short delay (20 min), a 12-hr wake delay, or a 12-hr sleep delay. Goal execution declined after the 12-hr wake delay relative to the short delay. In contrast, goal execution was relatively preserved after the 12-hr sleep delay relative to the short delay. The sleep-enhanced goal execution was not accompanied by a decline in performance of an ongoing task in which the prospective memory goal was embedded, which suggests that the effect was not a consequence of attentional resources being reallocated from the ongoing task to the prospective memory goal. Our results suggest that consolidation processes active during sleep increase the probability that a goal will be spontaneously retrieved and executed.

Dissociable Neural Routes to Successful Prospective Memory

Identifying the processes by which people remember to execute an intention at an appropriate moment (prospective memory) remains a fundamental theoretical challenge. According to one account, top-down attentional control is required to maintain activation of the intention, initiate intention retrieval, or support monitoring. A diverging account suggests that bottom-up, spontaneous retrieval can be triggered by cues that have been associated with the intention and that sustained attentional processes are not required. We used a specialized experimental design and functional MRI methods to selectively marshal and identify each process. Results revealed a clear dissociation. One prospective-memory task recruited sustained activity in attentional-control areas, such as the anterior prefrontal cortex; the other engaged purely transient activity in parietal and ventral brain regions associated with attentional capture, target detection, and episodic retrieval. These patterns provide critical evidence that there are two neural routes to prospective memory, with each route emerging under different circumstances.

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.

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.