Tactile short-term memory

Subjects tried to recall the location of a tactile stimulus on the underside of the forearm after delays of 0, 3, 5, 10, 15, 30, 45 and 60 sec. When “rehearsal” was prevented by requiring subjects to count backwards during the delay, accuracy of recall decreased systematically reaching an asymptote after 45 sec. When subjects were left free to “rehearse,” this did not affect the decline in accuracy over the first 10 sec. Between 10 and 15 sec. there was a significant increase in accuracy followed by a slow decline which had not reached asymptote by 60 sec. It is suggested that tactile STM (short-term memory) depends on two processes, a fading sensory trace which is unaffected by distraction and a less labile system which does not appear to be verbal but which depends on “rehearsal.”     

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.     

Influence of articulation rate on two memory tasks in young and older adults

This study investigated the relation between phonological loop functioning and age. Phonological loop is a time-based subsystem of the Working Memory Model of Baddeley and Wilson, which uses rehearsal of information as an active process to avoid phonological decay. Performance differences were examined between young and older adults in two speech-based memory tasks, such as the immediate serial recall of words and the Digit Ordering Task. Analysis showed that performance on both tasks was lower for the older group. Articulation rate was also measured to test the hypothesis that the impairment of some cognitive functions in adults can be associated to their slowness or the greater time needed by older adults for the rehearsal process. A significant negative correlation was found for articulation rate with age. When the effect of articulation rate on Serial Recall and Digit Ordering Tasks was partialled out, the difference between the two groups was eliminated.     

Cognitively impaired older adults exhibit comparable difficulties on naturalistic and laboratory prospective memory tasks

Prospective memory, or remembering future intentions, is critical for independent living for all ages, but especially older adults. Previous laboratory research has found that cognitively impaired older adults may have particular difficulties with prospective memory, but previous studies have not examined whether these difficulties occur in everyday life. In normal ageing, a dissociation between settings has been observed, with older adults selectively impaired in laboratory (but not naturalistic) contexts. Consequently, in the present study 15 cognitively impaired older adults were compared to demographically matched controls on laboratory and naturalistic measures of prospective memory. The results indicated that the cognitively impaired group performed more poorly on both measures, with the magnitude of the deficit comparable across setting. These results indicate that for older adults who present with cognitive impairment prospective memory deficits observed in laboratory settings may be a valid indicator of difficulties experienced executing delayed intentions in everyday life. Copyright © 2008 John Wiley & Sons, Ltd.     

Task preparation based on precues versus memory: Precues lead to superior performance with two tasks but not with four tasks

There is considerable evidence that task switching proceeds more efficiently with preparation based on explicit precues than on the basis of a learned sequence of tasks. However, this evidence stems almost exclusively from experiments in which participants switched between only two tasks. In two experiments stronger preparation effects with explicit precues compared to memory-based preparation was replicated with two tasks. With four tasks, however, preparation based on memory was at least as efficient as preparation based on precues. A third experiment ruled out the possibility that this latter finding was due to increased difficulty of cue processing with two-dimensional cues. These findings question the generalisability of observations regarding preparation effects that are based on two-task situations. It is suggested that one crucial factor regarding the relative efficiency of precue-based and memory-based preparation pertains to the fact that with two tasks, the relevant task can be determined by knowing only the previous task and whether a switch is required or not. This is not possible with four tasks that require a more elaborated task representation at the outset, which in turn may be more apt to support memory-based preparation.     

Memory for to-be-performed tasks versus memory for performed tasks

Memory for subject-performed tasks—that is, for simple actions such as lifting a pen, which subjects perform overtly—is better than memory for verbal tasks—that is, when subjects only listen to the action phrases. Here I investigated whether this effect depends on actual performance or whether it also shows up when there is only an intention to perform the task. Koriat, Ben-Zur, and Nussbaum (1990) found that the intention to perform items at test enhanced free recall more than did verbal tasks. Brooks and Gardiner (1994), however, were not able to replicate this finding. In four experiments, I attempted to reconcile this discrepancy by comparing subject-performed tasks, to-beperformed tasks, and verbal tasks under different conditions. The outcome depended on whether a within-subjects design or a between-subjects design was used. In the between-subjects design, memory for subject-performed tasks was better than memory for to-be-performed tasks, and both of these led to better recall performance than did verbal tasks. In a within-subjects design, in contrast, memory for to-be-performed tasks was no different from memory for verbal tasks. These results were independent of whether the test mode was congruent or incongruent. Thus, the discrepant findings of Koriat et al. and of Brooks and Gardiner seem to be due to the design used, pointing to encoding processes as the critical variable. The present results are interpreted to show that actual performance of actions at study provides more information than does only the intention to perform actions at test.     

The effect of orienting tasks on recognition memory

The effect of orienting tasks on recognition memory for words and faces was investigated. It was found that relevant orienting tasks improved recognition memory for both classes of stimuli compared with a nonrelevant orienting task and the control condition of testing recognition memory without an orienting task. Attention is drawn to the possibility of qualitative differences between recall and recognition for the effect of orienting tasks. The findings are related to recognition theories. It is suggested that the findings lend support to those theories which hold that retrieval processes play a major role in recognition memory.     

Interruptions create prospective memory tasks

When the theory of prospective memory is brought to bear on the ubiquitous experience of failing to resume interrupted tasks, the cognitive reasons for these failures may be understood and addressed. We examine three features of interruptions that may account for these failures: (1) Interruptions often abruptly divert attention, which may prevent adequate encoding of an intention to resume and forming an implementation plan, (2) New task demands after an interruption's end reduce opportunity to interpret resumption cues, (3) The transition after an interruption to new ongoing task demands is not distinctive because it is defined conceptually, rather than by a single perceptual cue. Hypotheses based on these three features receive support from two experiments that respectively manipulate encoding and retrieval conditions. The data support our contention that interrupted tasks are a special case of prospective memory, and allow us to suggest practical ways of reducing vulnerability to resumption failure. Copyright © 2008 John Wiley & Sons, Ltd.     

Differential effects of age on prospective and retrospective memory tasks in young, young-old, and old-old adults

Remembering to do something in the future (termed prospective memory) is distinguished from remembering information from the past (retrospective memory). Because prospective memory requires strong self-initiation, Craik (1986) predicted that age decrements should be larger in prospective than retrospective memory tasks. The aim of the present study was to assess Craik's prediction by examining the onset of age decline in two retrospective and three prospective memory tasks in the samples of young (18-30 years), young-old (61-70 years), and old-old (71-80 years) participants recruited from the local community. Results showed that although the magnitude of age effects varied across the laboratory prospective memory tasks, they were smaller than age effects in a simple three-item free recall task. Moreover, while reliable age decrements in both retrospective memory tasks of recognition and free recall were already present in the young-old group, in laboratory tasks of prospective memory they were mostly present in the old-old group only. In addition, older participants were more likely to report a retrospective than prospective memory failure as their most recent memory lapse, while the opposite pattern was present in young participants. Taken together, these findings highlight the theoretical importance of distinguishing effects of ageing on prospective and retrospective memory, and support and extend the results of a recent meta-analysis by Henry, MacLeod, Phillips, and Crawford (2004).     

Working memory training improvements and gains in non-trained cognitive tasks in young and older adults

Previous studies on working memory training have indicated that transfer to non-trained tasks of other cognitive domains may be possible. The aim of this study is to compare working memory training and transfer effects between younger and older adults (n = 60). A novel approach to adaptive n-back training (12 sessions) was implemented by varying the working memory load and the presentation speed. All participants completed a neuropsychological battery of tests before and after the training. On average, younger training participants achieved difficulty level 12 after training, while older training participants only reached difficulty level 5. In younger participants, transfer to Verbal Fluency and Digit Symbol Substitution test was found. In older participants, we observed a transfer to Digit Span Forward, CERAD Delayed Recall, and Digit Symbol Substitution test. Results suggest that working memory training may be a beneficial intervention for maintaining and improving cognitive functioning in old age.     

Functional decay of memory for tasks

Correct performance often depends on remembering the task one has been instructed to do. When the task periodically changes, memory for the current task must decay (lose activation) to prevent it from interfering with memory for the next task when that is encoded. Three task-switching experiments examine this decay process. Each shows within-run slowing, a performance decline occurring as memory for the current task decays. In experiment 1, slowing is attenuated when memory for the task is optional, suggesting that memory is indeed causal. Experiment 2 finds slowing despite a flat hazard rate for task instructions, suggesting that slowing is not an artifact of instruction anticipation. Experiment 3 finds slowing in the familiar alternating-runs paradigm (Rogers & Monsell, 1995), suggesting that it may lurk elsewhere. A process model of activation explains within-run slowing and relates it to switch cost and "restart cost" (Allport & Wylie, 2000) in functional terms.     

Positive effects of subclinical depression in prospective memory and ongoing tasks in young and old adults

Results reported in the literature show that depression can have either negative or neutral effects on prospective memory (PM). The goal of the present study was to broaden the analysis of depression-related effects on PM, with regard to the possibility that subclinical depression may have positive influence on PM. A total of 120 participants from four groups (young/old, subclinically depressed/non-depressed) completed event- and time-based PM tasks embedded in the linear orders task or stories task, respectively. In the event-based PM task no effects of depression were found, whereas depressed participants were more accurate in the time-based PM task, where higher monitoring during the last minute of the task was observed. It was also found that depressed participants built a mental model in the linear orders task more accurately than controls. Results of the present study are discussed with reference to the analytical rumination hypothesis.     

Dissociative tendencies and memory performance on directed-forgetting tasks

The current article presents two studies that aimed to replicate DePrince and Freyd's (2001, 2004) studies demonstrating that high and low dissociators differentially recall neutral and trauma words under conditions of varying cognitive load. We did not find this effect. This lack of replication was apparent for both free recall and word recognition memory and in both studies. In effect, we found little evidence to support betrayal trauma theory, yet observed increased memory fallibility, as demonstrated by lower general recall and (in one study) commission errors, in high dissociators.     

Tactile short-term memory in relation to the two-point threshold

The purpose of the present work was to discover whether there was a relationship between the sensitivity of a body site as measured by the two-point threshold and the degree or rate of forgetting of a location stimulated at that body site. In Experiment I, it was found that the higher the two-point threshold, the greater the distance between two successive points of stimulation erroneonously thought to be identical (12 body sites). In Experiment II, it was found that forgetting over time was greater when the retention interval was filled with movement or other tactile stimulation than when the retention interval was unfilled (six body sites). It was concluded that highly sensitive areas also show the least degree of forgetting as compared with less sensitive sites, but this statement should be qualified in various ways.     

Encoding processes in memory scanning tasks

Three experiments are presented that deal with the effect of stimulus probability on the encoding of both alphanumeric characters and nonsense figures. Experiment I replicated a previous finding of an interaction between stimulus probability and stimulus quality in a memory scanning task with numbers as stimuli. Experiments II and III investigated the same paradigm with unfamiliar visual forms as stimuli, and no interaction was found. Results were interpreted as showing that probability affects the encoding mechanism only when the encoding process results in a representation of the name of the stimulus. When stimulus materials are visual forms without names, probability does not appear to affect encoding processes.     

A framework for reproductive memory tasks

The present papers present a framework for reproductive memory tasks. It is proposed that the notion of predictability of presentation is of prime importance to performance in reproductive tasks and that this notion may be decomposed into three critical dimensions, viz. the item expectancy, the type-of-recall and recall expectancy dimensions. The first dimension refers to the manipulation of inter-item intervals; the second to backward, forward or free recall and the third to when recall is prompted. Moreover, a study was conducted, wherein these three dimension were combined. The main results demonstrated superior performance for prerecency items (the first four items) with fast inter-item intervals in the beginning of list presentation and also reliable effects for recency items (the last four items). Precueing and postcueing (recall expectancy) interacted with the item expectancy dimension and also with the type of recall expectancy dimension in systematic ways. The data obtained could not be accouted for a traditional encoding, storage, retrieval or rehearsal terms, whereas the predictability notion seemed more viable. Finally, implications for a general interactionistic theory were also discussed, where the interplay between cognitive skills and predictability characteristics of the task constitute the basic factors.     

Preferences for emotional information in older and younger adults: a meta-analysis of memory and attention tasks

The authors conducted a meta-analysis to determine the magnitude of older and younger adults' preferences for emotional stimuli in studies of attention and memory. Analyses involved 1,085 older adults from 37 independent samples and 3,150 younger adults from 86 independent samples. Both age groups exhibited small to medium emotion salience effects (i.e., preference for emotionally valenced stimuli over neutral stimuli) as well as positivity preferences (i.e., preference for positively valenced stimuli over neutral stimuli) and negativity preferences (i.e., preference for negatively valenced stimuli to neutral stimuli). There were few age differences overall. Type of measurement appeared to influence the magnitude of effects; recognition studies indicated significant age effects, where older adults showed smaller effects for emotion salience and negativity preferences than younger adults.     

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.