Normal aging and prospective memory

We develop a laboratory paradigm for studying prospective memory and examine whether or not this type of memory is especially difficult for the elderly. In two experiments, young and old subjects were given a prospective memory test (they were asked to perform an action when a target event occurred) and three tests of retrospective memory (short-term memory, free recall, and recognition). From the perspective that aging disrupts mainly self-initiated retrieval processes, large age-related decrements in prospective memory were anticipated. However, despite showing reliable age differences on retrospective memory tests, both experiments showed no age deficits in prospective memory. Moreover, regression analyses produced no reliable relation between the prospective and retrospective memory tasks. Also, the experiments showed that external aids and unfamiliar target events benefit prospective memory performance. These results suggest some basic differences between prospective and retrospective memory.     

Prospective memory across the lifespan: Investigating the contribution of retrospective and prospective processes

Prospective memory performance follows an inverted U-shaped function across the lifespan. Findings on the relative contribution of purely prospective memory and retrospective memory processes within prospective memory to this trajectory are scarce and inconclusive. We analyzed age-related differences in prospective memory performance across the lifespan in a cross-sectional design including six age groups (N = 99, 7–83 years) and investigated possible mechanisms by experimentally disentangling the relative contributions of retrospective memory and purely prospective memory processes. Results confirmed the inverted U-shaped function of prospective memory performance across the lifespan. A significant interaction between process type and age group was observed indicating differential relative contributions of retrospective memory and purely prospective memory processes on the development of prospective memory performance. Our results showed that mainly the pure prospective memory processes within prospective memory lead to lower prospective memory performance in young children and old adults. Moreover, the relative contributions of the retrospective memory and purely prospective memory processes are not uniform at both ends of the lifespan, i.e., in later adulthood the purely prospective memory processes seem to determine performance to an even greater extent than in childhood. Nevertheless, age effects were also observed in the retrospective component which thus contributed to the prospective memory performance differences between the age groups.     

The role of age and inhibitory efficiency in working memory processing and storage components

In this study, we examined the extent to which inhibitory efficiency accounted for age-related decline in the processing and storage components of working memory. Older and younger adults performed a sequential task, which served as an index of deletion-type inhibition (the ability to suppress no-longer-relevant information). The reading span task was used to measure working memory components by examining processing accuracy, processing time, and end-word recall of sentences presented. Reduced inhibitory efficiency, which was poorer in older adults, predicted age-related decline in recall, over and above the effects of processing speed. Similar results were observed for processing accuracy, although the age effect in this component was marginal. These results highlight the important role of deletion-type inhibition in explaining age-related decline in working memory performance, particularly in the storage component, and extend previous research by examining this relationship at a componential level.     

The role of age and inhibitory efficiency in working memory processing and storage components

In this study, we examined the extent to which inhibitory efficiency accounted for age-related decline in the processing and storage components of working memory. Older and younger adults performed a sequential task, which served as an index of deletion-type inhibition (the ability to suppress no-longer-relevant information). The reading span task was used to measure working memory components by examining processing accuracy, processing time, and end-word recall of sentences presented. Reduced inhibitory efficiency, which was poorer in older adults, predicted age-related decline in recall, over and above the effects of processing speed. Similar results were observed for processing accuracy, although the age effect in this component was marginal. These results highlight the important role of deletion-type inhibition in explaining age-related decline in working memory performance, particularly in the storage component, and extend previous research by examining this relationship at a componential level.     

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.     

Contents Index Volume 8

In a group of 62 young and 75 older subjects, LISREL models were used to predict ordered list recall from age category, self-reported strategy use and selected cognitive abilities. It was found that: (a) age differences in the strategies of associating and repetition/testing were completely explained by speed of mental processing and associative memory; (b) only these two age-related strategies were efficacious strategies, the one not age-related strategy (concentrating) was not; (c) a large proportion of the age-related variance in list recall performance was mediated by speed and associative memory; and (d) this influence of speed and associative memory on ordered list recall was partly mediated by strategies. These results support a moderate version of the production deficiency explanation of memory aging, in which age differences in efficacious strategy use are explained by age differences in basic cognitive abilities.     

工作记忆和感觉运动速度在心算加工年老化过程中的作用

对心算加工年老化研究有助于阐明认知老化规律,然而有关心算老化的少量研究结果仍存在不一致甚至矛盾之处。导致这种不一致的原因十分复杂,表面上看,不同认知老化研究所采用的统计方法不尽相同导致了结果的歧异。例如,在心算的年老化研究中,有的研究结论基于群体的数据分析,如层级回归分析(hierarchical regres-sion analyses)或方差分析,如Sahhouse和Coon(1994);另有一些研究先对每一个体数据作线性回归分析,如此得到斜率和截距(分别表示心算的中枢加工时间和外周感觉运动时间),然后再行层级回归分析或方差分析,如Al-len等(1992,1997)。这两类统计分析所得的结果很不一致。从理论上看,只要所采用的统计方法是合理的,统计方法的不尽相同应不会导致矛盾。但在实际情况下,统计分析误差增加了结论不一致的可能性,从而增大了揭示心算老化复杂性规律的难度。事实上,心算活动的年龄差异可能来自于记忆、加工速度等不同认知资源的老化差异。为了深入探讨这一问题,我们进一步研究了工作记忆和感觉运动速度在心算加工年老化过程中的作用。被试共161人,20—79岁,身体健康,受教育年限12年以上,以10岁段划分为6个年龄组,组间文化程度基本匹配。被试任务包括：(1)连续减法心算,分别为1000—3、1000—7、1000—13及1000—17等4种,在排除了被试看屏幕和按键的感觉运动时间后得到心算所需的时间;(2)数字计算工作记忆,根据工作记忆对信息同时进行加工和储存的特点,要求被试计算完题后再回忆答案,以获得工作记忆广度指标;(3)“数字复制”(digit copying),以获得感觉运动速度指标。实验在386微机上进行。对所得数据分别进行了上述群体数据与个体数据分析。两种数据分析方法得到了相同的结果,一致表明,在控制工作记忆与感觉运动速度的年龄差异后,心算活动的年龄差异显著降低。而且,控制感觉运动速度的年龄差异后心算活动年龄差异的降低程度要大于控制工作记忆的年龄差异后心算活动年龄差异的降低程度。这说明,感觉运动速度在心算加工年老化过程中发挥了更大作用。但是,工作记忆与感觉运动速度二者的年龄差异并不能完全解释心算活动的年龄差异,表明心算加工的年老化存在其特殊性过程,不支持认知老化的普遍减慢假说(genenalized slowing hypotllesis)。     

Executive Function and Processing Resources as Predictors of Adult Age Differences in the Implementation of Encoding Strategies

This research examined adult age differences in recall of word lists under different encoding conditions: association (story generation), rehearsal, and a control condition. Executive function and cognitive processing resources (speed and working memory) were investigated as mediators of these age differences. Younger (aged 17-48 years) and older (aged 65-88 years) adults completed a battery of tests of executive function, speed of information processing, working memory, and recall. Age differences in recall were evident for those who used the complex association encoding strategy only. For those using the association strategy, an examination of encoding strategy protocols revealed age differences in the integration of words, which were also related to subsequent recall performance. The association between integration and recall was accounted for by executive function and working memory, but not by speed of processing. Speed accounted for age differences in recall but its contribution to recall was largely independent from that of the impact of integration during encoding.     

Cognitive Mediators of Age-Related Differences in Language Comprehension and Verbal Memory Performance

The present study tried to specify how much processing speed, working memory capacity, and inhibition capability contribute to the effects of aging on language performance. An individual-differences approach was used to examine the component processes that predict performance in language comprehension and verbal long-term memory tasks. A total of 151 participants aged 31-80 completed language processing tasks and a battery of tasks designed to assess processing speed, working memory, and resistance to interference. Latent-construct structural equation modeling was used to examine the relationships of these factors and age to different types of language tasks. The best fit model showed first that all the significant relationships between age and language performance are mediated through reductions in speed, resistance to interference, and working memory; this confirms the validity of the general factor approach of age-related differences in cognitive performance. The best fit model, however, also showed that the contribution of speed and resistance to interference is indirect and mediated by working memory, which appears to play a crucial role in explaining age-related differences in language performance.     

基于事件的前瞻性记忆的年老化

采用类别判断任务作为正在进行任务,采用Einstein的研究范式探讨了前瞻性记忆是否随年龄的老化而出现年老化现象。结果表明,当前瞻性记忆任务和当前进行的任务要求的认知过程一致时,前瞻性记忆成绩不会随增龄下降;当前瞻性记忆任务和当前进行的任务要求的认知过程不一致时,前瞻性记忆出现了年老化现象;前瞻性记忆成绩和自由回忆成绩无显著相关     

Pro- and Retrospective Memory in Late Adulthood

Everyday tasks, such as getting groceries en route from work, involve two distinct components, one prospective (i.e., remembering the plan) and the other retrospective (i.e., remembering the grocery list). The present investigation examined the size of the age-related performance declines in these components, as well as the relationship between these components and age-related differences in processing resources. The subjects were 133 community-dwelling adults between 65 and 95 years of age. They completed a large battery of tests, including tests of pro- and retrospective memory as well as tests for indexing processing resources. The results showed similar age-related declines in pro- and retrospective memory. There was only a weak relationship between pro- and retrospective memory, and the age-related decline in processing resources was related more strongly to retro- than prospective memory.     

Effects of age and anxiety on episodic memory: selectivity and variability

Selective age-related differences in source memory relative to item memory, and individual differences in memory performance in relation to anxiety were explored with high- and low-anxious subjects screened from normal young and elderly adults. They were read false facts about the locations of well-known and unknown sights in a male or female voice. Intentional and incidental learning instructions were administered for source memory. Selective age-related deficits in source memory were observed under both encoding conditions. Higher level of anxiety was related to lower memory performance only in the old group; this relation was stronger in source recall. The findings suggest that the presence of such selectivity is unrelated to the tradeoff between item encoding and source encoding. Anxiety affects the variability, and mediates the selectivity of age effects on episodic memory.     

Verbal knowledge, working memory, and processing speed as predictors of verbal learning in older adults

The present study aimed at modeling individual differences in a verbal learning task by means of a latent structured growth curve approach based on an exponential function that yielded 3 parameters: initial recall, learning rate, and asymptotic performance. Three cognitive variables-speed of information processing, verbal knowledge, working memory-and the participant's age were included in the model in order to explain individual differences in the learning parameters. The data come from the second wave of the Zurich Longitudinal Study on Cognitive Aging (D. Zimprich, Martin, et al., 2008) comprising 334 participants ranging in age from 66 to 81 years (M = 74.43, SD = 4.41). Among the logistic, the Gompertz, and the hyperbolic function, the exponential function described the data best. Reliable individual differences were found in all 3 learning parameters. The cognitive predictor variables affected the verbal learning parameters differentially: All 3 predictors affected positively initial recall, the asymptotic performance increased with better working memory and faster processing speed, and the learning rate was positively associated with verbal knowledge only. Age did not affect the learning parameters but correlated negatively with working memory and processing speed. The finding of large and reliable individual differences in learning is seen as evidence that the potential for positive change, or plasticity in adulthood is maintained and that it is worthwhile to enhance the determinants of learning or learning itself.     

PROCESSING SPEED, WORKING MEMORY, AND FLUID INTELLIGENCE:

Abstract— Processing speed, working memory capacity, and fluid intelligence were assessed in a large sample ( N = 214) of children, adolescents, and young adults (ages 7 to 19 years) Results of path analyses revealed that almost half of the age-related increase in fluid intelligence was mediated by developmental changes in processing speed and marking memory and nearly three fourths of the improvement in working memory was mediated by developmental changes in processing speed Moreover, even when age-related differences in speed, working memory and fluid intelligence were statistically controlled, individual differences in speed had a direct effect on working memory capacity which, in turn was a direct determinant of individual differences in fluid intelligence     

Cognitive Mechanisms Underlying Decrements in Mental Synthesis in Older Adults

The extent and nature of age-related differences in mental synthesis was examined in light of Baddeley's working memory model and resource theories. Mental synthesis performance of 30 young, young-old, middle-old and old-old adults was examined using a dual-task experiment and individual differences approach. Age-related differences in mental synthesis were shown, with an unprecedented heightened decrement evident after the age of 85. The central executive was not a mechanism of this decline. Executive function, speed of information processing, and working memory capacity were mechanisms underlying this decline, and together accounted for 86% of the age-related variance in mental synthesis. Environmental support enhanced mental synthesis.     

Ability correlates of memory performance in adulthood and aging

The predictive relationships between an array of cognitive process and intellectual ability variables and text- and word-recall performance were examined. A sample of 584 men and women from 3 age groups (19-36, 55-69, and 70-86 years) completed a battery of 23 tasks marking 2 latent criterion variables and 10 latent predictor variables. The results indicated that (a) individual differences in process and ability variables predict performance on text and word recall, accounting for approximately half of the variance; (b) the pattern of predictors is quite similar for text and word recall; (c) age-related differences in text and word recall can be substantially accounted for by individual differences in constituent abilities, particularly indicators of verbal speed and working memory; and (d) there is some evidence to suggest that the pattern of ability-performance relationships varies across age, but such interactions appear to be relatively small.     

Prospective memory performance in preschoolers: Inhibitory control matters

The present study focuses on prospective memory in preschoolers. We specifically investigated the effects of age, retrospective memory, and task interruption on prospective memory performance. In the first experiment, testing 60 children aged 3, 4 and 5 years with a prospective memory task that required active ongoing task interruption we obtained an age effect indicating better prospective memory performance for the two older cohorts. Varying retrospective memory load did influence prospective memory response time but did not affect prospective memory accuracy. However, retrospective memory performance showed an age effect and individual differences in retrospective memory ability were related to individual differences in prospective memory performance, even after partialling age. In the second study, we applied a prospective memory task that did not require active ongoing task interruption. Here, testing 62 children aged 3, 4 and 5 years we still found an age effect in retrospective memory but neither an effect of age nor retrospective memory on prospective memory performance. It is concluded that preschoolers even at the age of 3 years can perform prospective memory tasks to a certain extent. Moreover, while retrospective memory still seems to be somewhat related to prospective memory in preschoolers, inhibitory control required for ongoing task interruption seems to be an especially important factor influencing task performance in preschoolers.     

Recall of Subject-Performed Tasks,Verbal Tasks,and Cognitive Activities Across the Adult Life Span: Parallel Age-Related Deficits

Motor activity during encoding of verbal information has been suggested to reduce age differences in episodic memory. Here we examined memory for sentences encoded with enactment (SPTs, subject-performed tasks) or without enactment (VTs, verbal tasks) in a population-based sample consisting of 10 groups ranging in age from 35 to 80 years (N = 1000). Memory performance was assessed by immediate free- and category-cued recall. Degree of clustering was measured by the adjusted ratio of clustering score. Recall of cognitive activities served as a complementary measure of memory for performed tasks. Sentence recall showed a gradual decline across age, of about the same magnitude for SPTs and VTs, in both free and cued recall. Clustering in free recall was higher for SPTs than for VTs, but there were no age differences in clustering. A pattern of gradual decline from age 35 was observed also in activity recall, regardless of whether the activities involved motor activity or not. Across the memory measures, differences in education accounted for all of the age-related variance in performance among the younger (35-55 years) but not the older groups (60-80 years), suggesting that genuine aging effects in these measures are more prominent in old age. Together, the results indicate that age differences in episodic memory, in line with most, if not all, types of encoding support, generalize across the performed/non-performed distinction.     

Speech-processing capacity in young and older adults: a dual-task study

Adult age differences in processing speech were examined with a dual-task paradigm. Subjects listened to spoken passages for later recall while performing a concurrent reaction time task intended to index cognitive capacity usage on the speech memory task. Age differences in secondary task decision latencies were eliminated when subgroups of young and older subjects were matched on working memory span. These findings are interpreted as showing that an age-related reduction in working memory efficiency contributes to age differences in processing discourse for memory.     

Temporal clustering and sequencing in short-term memory and episodic memory

A model of short-term memory and episodic memory is presented, with the core assumptions that (a) people parse their continuous experience into episodic clusters and (b) items are clustered together in memory as episodes by binding information within an episode to a common temporal context. Along with the additional assumption that information within a cluster is serially ordered, the model accounts for a number of phenomena from short-term memory (with a focus on serial recall) and episodic memory (with a focus on free recall). The model also accounts for the effects of aging on serial and free recall, apparent temporal isolation effects in short- and long-term memory, and the relation between individual differences in working memory and episodic memory performance.