Episodic feeling-of-knowing accuracy and cued recall in the elderly: evidence for double dissociation involving executive functioning and processing speed

This research investigated adult age differences in a metamemory monitoring task-episodic feeling-of-knowing (FOK) and in an episodic memory task-cued recall. Executive functioning and processing speed were examined as mediators of these age differences. Young and elderly adults were administered an episodic FOK task, a cued recall task, executive tests and speed tests. Age-related decline was observed on all the measures. Correlation analyses revealed a pattern of double dissociation which indicates a specific relationship between executive score and FOK accuracy, and between speed score and cued recall. When executive functioning and processing speed were evaluated concurrently on FOK and cued recall variables, hierarchical regression analyses showed that executive score was a better mediator of age-related variance in FOK, and that speed score was the better mediator of age-related variance in cued recall.     

Executive functioning and processing speed in age-related differences in time estimation: a comparison of young,old, and very old adults

Age-related differences in time estimation were examined by comparing the temporal performance of young, young–old, and old–old adults, in relation to two major theories of cognitive aging: executive decline and cognitive slowing. We tested the hypothesis that processing speed and executive function are differentially involved in timing depending on the temporal task used. We also tested the assumption of greater age-related effects in time estimation in old–old participants. Participants performed two standard temporal tasks: duration production and duration reproduction. They also completed tests measuring executive function and processing speed. Findings supported the view that executive function is the best mediator of reproduction performance and inversely that processing speed is the best mediator of production performance. They also showed that young–old participants provide relatively accurate temporal judgments compared to old–old participants. These findings are discussed in terms of compensation mechanisms in aging.     

Do attentional capacities and processing speed mediate the effect of age on executive functioning?

The executive processes are well known to decline with age, and similar data also exists for attentional capacities and processing speed. Therefore, we investigated whether these two last nonexecutive variables would mediate the effect of age on executive functions (inhibition, shifting, updating, and dual-task coordination). We administered a large battery of executive, attentional and processing speed tasks to 104 young and 71 older people, and we performed mediation analyses with variables showing a significant age effect. All executive and processing speed measures showed age-related effects while only the visual scanning task performance (selective attention) was explained by age when controlled for gender and educational level. Regarding mediation analyses, visual scanning partially mediated the age effect on updating while processing speed partially mediated the age effect on shifting, updating and dual-task coordination. In a more exploratory way, inhibition was also found to partially mediate the effect of age on the three other executive functions. Attention did not greatly influence executive functioning in aging while, in agreement with the literature, processing speed seems to be a major mediator of the age effect on these processes. Interestingly, the global pattern of results seems also to indicate an influence of inhibition but further studies are needed to confirm the role of that variable as a mediator and its relative importance by comparison with processing speed.     

Age-related changes in duration reproduction: involvement of working memory processes

The aim of the present research was to study age-related changes in duration reproduction by differentiating the working memory processes underlying this time estimation task. We compared performances of young and elderly adults in a duration reproduction task performed in simple and concurrent task conditions. Participants were also administered working memory tests to measure storage and central executive functions. Findings indicated a differential involvement of working memory storage and central executive functions in age-related differences in temporal tasks. The limited storage capacities explained age-related changes in the simple task of duration reproduction, and the dysfunctioning of central executive functions accounted for age-related changes in duration reproduction performed in a concurrent task condition, which involves greater attentional resources.     

抑制和加工速度与液态智力的年老化

研究抑制能力和加工速度在液态智力年老化过程中的相对作用。被试为142名18~85岁健康成年人,完成包括抑制优势反应、加工速度和液态智力共13项测验。分层回归分析显示,抑制能力与年龄相关的特异性变异,在控制简单的速度变量时较控制复杂的速度变量时更大;结构方程分析表明,对液态智力年老化的中介作用,当选取较复杂的速度变量时加工速度的作用更大,而当选取较简单的速度变量时抑制能力的作用更大。研究结果表明,在液态智力的年老化过程中,除了加工速度的作用之外,抑制能力也起重要的中介作用。该结果为认知年老化的抑制理论和执行衰退假说提供了认知行为学研究的证据,并且对加工速度理论作了有益的补充和修正     

The cerebellum in thought and action: a fronto-cerebellar aging hypothesis

Normal aging is associated with deficits in both memory and executive control. While a number of theories of cognitive aging have proposed that decrements in frontally mediated executive control processes can account for many of the age-related changes observed, the models proposed to date have not adequately accounted for age changes in processing speed, intra-individual variability and automaticity of information processing. These basic aspects of information processing efficiency may be of central importance for our understanding of age-related cognitive changes and more elaborate neurological models are needed that incorporate explanatory mechanisms which account for their influence. In this paper, it is proposed that the dual role played by frontal and cerebellar degeneration and the disruption of fronto-cerebellar feedback and feedforward control loops may be of central importance for a model of age-related changes in processing speed, intra-individual variability, automaticity, and higher level cognitive functions like memory and executive control.     

Measures of fluency as predictors of incidental memory among older adults

This study investigated fluency performance as a mediator of age-related declines in incidental memory performance as both are thought to rely on strategic retrieval processes. A large sample of community dwelling older adults completed a battery of tests assessing fluency, verbal knowledge, speed of information processing, and incidental recall. Fluency measures included initial and excluded letter fluency and the Uses for Objects Test, and they were assumed to reflect increasing reliance on strategic retrieval search. Speed emerged as the best mediator of age-related variance in incidental recall, and Uses for Objects Test performance added to the variance after controlling for verbal knowledge and speed. The results suggest that age-related decline in incidental recall is largely due to speed and the strategic search of memory.     

Differential trajectories of age-related changes in components of executive and memory processes

Several studies have demonstrated age-related declines in general executive function and memory. In this study, we examined cross-sectional and longitudinal age effects in more specific cognitive processes that constitute executive function and memory. We postulated that, whereas some components of executive and memory functions would show age differences and longitudinal declines, other specific abilities would be maintained or even improve with repeated testing. In a sample of individuals ≥55 years old from the Baltimore Longitudinal Study of Aging, we found longitudinal declines in inhibition, manipulation, semantic retrieval, phonological retrieval, switching, and long-term memory over a maximum of 14 years follow-up. In contrast, abstraction, capacity, chunking, discrimination, and short-term memory were maintained or even improved longitudinally, probably due in part to repeated testing. Moreover, whereas several different abilities were correlated across participants' cross-sectional performance, longitudinal changes in performance showed more heterogeneous trajectories. Finally, compared with cross-sectional performance, longitudinal trajectories showed better distinction between participants with and those without later cognitive impairment. These results show that longitudinal cognitive aging of executive and memory functions is not a uniform process but a heterogeneous one and suggest that certain executive and memory functions remain stable despite age-related declines in other component processes. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Age-related differences in acquisition of perceptual-motor skills: working memory as a mediator

Aging is associated with reduced performance on information processing speed, memory, and executive functions tasks. Although older adults are also less apt in acquiring new perceptual-motor skills, it is unclear whether and how skill acquisition difficulties are associated with age-related general cognitive differences. We addressed this question by examining structural relations among measures of cognitive resources (working memory) and indices of perceptual-motor skill acquisition (pursuit rotor and mirror tracing) in 96 healthy adults aged 19-80 years of age. Three competing structural models were tested: a single (common) factor model, a dual correlated factors model, and a hierarchical dual-factor model. The third model provided the best fit to the data, indicating age differences in simple perceptual-motor skill are partially mediated by more complex abilities.     

Age related differences in metacognitive control: role of executive functioning

To examine whether aging affects metacognitive control, elderly and young adults carried out a readiness-recall task, in which subjects monitor their own learning procedure, allowing strategy manipulation (study time and rehearsal) to be measured. Age differences were observed in metamemory control performance. Younger adults were found to be better at adjusting study time and rehearsal to the task. Moreover, to determine whether age-related differences in strategy manipulation may mediate age-related differences in memory performance, performance on the readiness-recall task was compared to performance on an experimenter-paced task. Results indicated that younger adults recalled significantly more words in the readiness-recall task than in the experimenter test. This was not the case for older adults. Furthermore, a hierarchical regression analysis revealed that age-related differences in strategy manipulation mediate some age-related differences in memory performance. Our aim was also to determine whether metacognitive control is related to executive functions. Thus, all participants were administered standard neuropsychological tests used to assess executive functioning. Significant partial correlation appeared between metamemory control and executive functioning. Finally, a hierarchical regression analysis indicated that age-related decline in metamemory control may be largely the result of executive limitations associated with aging.     

Age-Related Differences in Acquisition of Perceptual-Motor Skills: Working Memory as a Mediator

ABSTRACT

Aging is associated with reduced performance on information processing speed, memory, and executive functions tasks. Although older adults are also less apt in acquiring new perceptual-motor skills, it is unclear whether and how skill acquisition difficulties are associated with age-related general cognitive differences. We addressed this question by examining structural relations among measures of cognitive resources (working memory) and indices of perceptual-motor skill acquisition (pursuit rotor and mirror tracing) in 96 healthy adults aged 19–80 years of age. Three competing structural models were tested: a single (common) factor model, a dual correlated factors model, and a hierarchical dual-factor model. The third model provided the best fit to the data, indicating age differences in simple perceptual-motor skill are partially mediated by more complex abilities.     

Individual differences in executive functions are almost entirely genetic in origin

Recent psychological and neuropsychological research suggests that executive functions--the cognitive control processes that regulate thought and action--are multifaceted and that different types of executive functions are correlated but separable. The present multivariate twin study of 3 executive functions (inhibiting dominant responses, updating working memory representations, and shifting between task sets), measured as latent variables, examined why people vary in these executive control abilities and why these abilities are correlated but separable from a behavioral genetic perspective. Results indicated that executive functions are correlated because they are influenced by a highly heritable (99%) common factor that goes beyond general intelligence or perceptual speed, and they are separable because of additional genetic influences unique to particular executive functions. This combination of general and specific genetic influences places executive functions among the most heritable psychological traits. These results highlight the potential of genetic approaches for uncovering the biological underpinnings of executive functions and suggest a need for examining multiple types of executive functions to distinguish different levels of genetic influences.     

Central executive system impairment in traumatic brain injury

The aim of the present study was to identify cognitive functions affected by traumatic brain injury (TBI) and to verify the mechanism underlying cognitive impairment. More precisely, cognitive deficits following TBI can be considered as a consequence of (a) a speed processing deficit, that is a general slowing of perceptual, motor and cognitive subroutines; (b) an impairment of the Central Executive System of working memory (CES).Thirty-seven patients were submitted to a neuropsychological battery, aimed to evaluate different cognitive functions.Results showed severe deficits in speed processing, divided attention,working memory, executive functions and long term memory.Regression analyses, performed to test the two hypotheses, showed that the working memory deficit hypothesis is able to explain divided attention, executive functions and long term memory deficits more than speed processing hypothesis.     

儿童青少年时期加工速度和执行功能在流体智力发展中的作用

以7~15岁儿童青少年为研究对象,考察加工速度和执行功能对流体智力的影响。研究结果表明,随着年龄的增长,感觉运动加工速度、知觉加工速度对流体智力从具有直接影响到只通过执行功能中的记忆更新成分产生间接影响,但这种影响存在年龄间的差异。在童年中期（7~9岁）,知觉加工速度对流体智力不仅具有直接的预测作用,还通过记忆更新对其产生间接的影响。童年晚期（10~12岁）,感觉运动加工速度和知觉加工速度不再对流体智力具有直接预测作用,都是通过记忆更新和抑制/转换合成成分间接对流体智力起作用。青春期（13~15岁）,知觉加工速度对流体智力只通过记忆更新产生间接影响。     

Age effects on different components of theory of mind

The effects of aging on the cognitive and affective dimensions of theory of mind (ToM), and on the latter’s links with other cognitive processes, such as information processing speed, executive functions and episodic memory, are still unclear. We therefore investigated these effects in young (n = 25), middle-aged (n = 20) and older adults (n = 25), using separate subjective and objective assessment tasks. Furthermore, a novel composite task probed participants’ abilities to infer both cognitive and affective mental states in an interpersonal context. Although age affected the objective ToM tests, results revealed a direct aging effect on the second-order ToM, but an indirect one on the first-order cognitive ToM, mediated mainly by age-related declines in executive functions. This study supports the notion of an age-related distinction between subjective and objective assessments of ToM, and confirms that ToM is a complex mental ability with several characteristics reliant to some extent on executive processes.     

Perceptual and lexical components of auditory repetition priming in young and older adults

In the present study, we examined whether age modulates the processing of lexical and perceptual information in auditory implicit and explicit memory tests. Young and older adults performed a surface encoding task on spoken and printed words and then either identified degraded words or made explicit recognition judgments. The implicit test of perceptual identification yielded no evidence of age-related declines in the processing of either lexical information or coarse perceptual details (modality of presentation). The same test, however, produced marked age-related declines in the processing of fine-grained perceptual details (voice) when subjects were not familiarized with the talkers' voices prior to the encoding task. Marked age differences were also observed in recognition memory. These findings suggest that although aging preserves the encoding and incidental retrieval of lexical and coarse perceptual information, it affects the encoding of fine-grained perceptual information and deliberate retrieval processes.     

Decomposing adult age differences in symbol arithmetic

A componential analysis was conducted to determine the locus of adult age differences in symbol arithmetic. Measures of the duration of two proposed components, substitution of digits for symbols and the addition or subtraction of the digits resulting from these substitutions, were obtained from 52 young adults and 52 older adults. Tests of working memory, perceptual speed, motor speed, and associative learning were also administered to all subjects. The results were most consistent with an interpretation postulating that the speed of many different cognitive processes decreases with increased age. Considerable age-related variance remained in the measures of symbol arithmetic performance after statistical control of working memory and associative learning performance, casting doubt on alternative hypotheses of the source of age-related differences in this task.     

The influence of complex working memory span task administration methods on prediction of higher level cognition and metacognitive control of response times

Participants between the ages of 18 and 80 were tested on a complex working memory span task that was administered either using a typical experimenter-paced method or using a method in which the processing component was presented at a fixed, limited-pace presentation rate. Path analyses revealed that even after controlling for individual differences in general processing speed, the limited-pace task predicted unique variance in episodic memory, executive functioning, and fluid intelligence, whereas the experimenter-paced task did not. For the experimenter-paced task, slower responses on the processing component of the task were associated with better recall, but only when individual differences in processing speed were controlled. These findings suggest that metacognitive control of response times affects recall from working memory span tasks, as well as the relationship between span task recall and high-level cognition. These results support resource-sharing explanations of working memory and suggest that limiting processing times using computer pacing of complex span tasks can be an effective way to efficiently measure working memory capacity.     

Impairment of executive functions in boys with attention deficit/hyperactivity disorder.

The main aim of the present study is to compare the efficiency of executive control processes in 24 boys with attention deficit/hyperactivity disorder (ADHD) and 58 normal controls of similar age (between 8 and 11 years). Three reaction time (RT) paradigms were utilized: a dual task that requires coordination of two tasks responses, a shift task that makes it necessary to disengage attention from one task and engage into another one, and a stimulus-response spatial compatibility task that requires participants to inhibit a prepotent response. Another purpose of the study is to examine whether Barkley's (1997) executive dysfunction or Sergeant et al.'s (1999) resource allocation/arousal model best account for the behavioral deficits associated with ADHD. Examination of raw RT data showed significantly poorer performance in ADHD children with respect to age-matched controls on both the higher-level cognitive functions of executive control and on lower-level abilities (e.g., speed of processing) of all tasks of this study. However, using proportional transformations of raw RT data, we could demonstrate that, in addition to differences in processing speed, also executive control processes were significantly impaired in children with ADHD.     

Changes in executive control across the life span: examination of task-switching performance

A study was conducted to examine changes in executive control processes over the life span. More specifically, changes in processes responsible for preparation and interference control that underlie the ability to flexibly alternate between two different tasks were examined. Individuals (N = 152) ranging in age from 7 to 82 years participated in the study. A U-shaped function was obtained for switch costs (i.e., the time required to switch between tasks compared with a repeated-task baseline), with larger costs found for young children and older adults. Switch costs were reduced with practice, particularly for children. All age groups benefited from increased preparation time, with larger benefits observed for children and older adults. Adults benefited to a greater extent than children when the interval between the response to one task and the cue indicating which task to perform next was lengthened, which suggested faster decay of interference from the old task set for adults than for children. A series of hierarchical analyses indicated that the age-related variance in task-switching performance is independent, at least in part, from the age-related variance in other cognitive processes such as perceptual speed and working memory. The results are discussed in terms of the development and decline of executive control processes across the life span.