Typical intellectual engagement and cognition in the ninth decade of life: The Lothian Birth Cohort 1921

Investment traits-the tendency to seek out and engage in cognitive activity-might affect intellectual growth across the life span, specifically the development from fluid to crystallized intelligence. Here we explore how childhood IQ at age 11 years, IQ at age 79, and the investment trait Typical Intellectual Engagement (TIE) at age 81 affect the mean level and change in verbal fluency scores, used as an indicator of crystallized intelligence, across the ages 79, 83, and 87 in the Lothian Birth Cohort 1921 (maximum N = 569; Deary, Whiteman, Starr, Whalley, & Fox, 2004). A first latent growth model showed significant variance in the mean level of verbal fluency and significant decline in verbal fluency from age 79 to age 87. The rate of change was invariant across study participants in the Lothian Birth Cohort 1921. A second model found that IQ at age 11 significantly predicted IQ at age 79 (β = .66; p < .001), which in turn predicted verbal fluency and TIE in the ninth decade of life with standardized path parameters of .46 and .15 (p < .001), respectively. TIE had a significant association with verbal fluency (β = .14, p = .002); together, IQ at age 11 and 79 and TIE accounted for 25.5% of the variance in verbal fluency. A final model identified the TIE subfactor of intellectual curiosity as a significant mediator of the effect of IQ on verbal fluency; the TIE subfactors abstract thinking, reading, and problem solving showed no significant associations. In summary, TIE-in particular, intellectual curiosity-significantly mediated the effects of IQ on crystallized intelligence in old age. Because there was no significant between-subjects variance in verbal fluency trajectories in the current study, neither TIE nor IQ were associated with individual differences in cognitive decline. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Placing inspection time, reaction time, and perceptual speed in the broader context of cognitive ability: The VPR model in the Lothian Birth Cohort 1936

The idea that information processing speed is related to cognitive ability has a long history. Much evidence has been amassed in its support, with respect to both individual differences in general intelligence and developmental trajectories. Two so-called elementary cognitive tasks, reaction time and inspection time, have been used to compile this evidence, but most studies have used either one or the other. Relations between speed and fluid intelligence have tended to be stronger than those between speed and crystallized intelligence, but studies testing this have confounded verbal abilities with crystallized intelligence and spatial/perceptual abilities with fluid intelligence. Questions have also been raised regarding whether speed contributes directly to general intelligence or to more specific cognitive abilities to which general intelligence also contributes. We used 18 ability and speed measures in the Lothian Birth Cohort 1936, assessed at approximately age 70, to construct alternative versions of the Verbal-Perceptual-Image Rotation (Johnson & Bouchard, 2005a) model of cognitive ability to test different hypotheses regarding these issues. Though differences in the extents to which our models fit the data were relatively small, they suggested that reaction and inspection time tasks were comparable indicators of information processing speed with respect to general intelligence, that verbal and spatial abilities were similarly related to information processing speed, and that spatial, verbal, and perceptual speed abilities were more directly related to information processing speed than was general intelligence. We discuss the theoretical implications of these results.     

The three-stratum theory of cognitive abilities: Test of the structure of intelligence across the life span

Recently a three-stratum theory of intelligence that combines the major aspects of Spearman's (1927) theory of general intelligence (g) and Horn and Cattell's (1966) theory of crystallized and fluid intelligence (G_f-G_c) has been proposed (Carroll, 1993a). The purpose of this study was to test the three-stratum theory using hierarchical confirmatory factor analysis with the LISREL computer program. Developmental changes in the structure of intelligence were also investigated. Results provided support for the three-stratum theory and suggested the possibility of intermediate factors between the second and third strata but did not support developmental changes in the organization of cognitive abilities over the life span.     

Typical intellectual engagement and cognition in old age

Typical Intellectual Engagement (TIE) comprises the preference to engage in cognitively demanding activities and has been proposed as a potential explanatory variable of individual differences in cognitive abilities. Little is known, however, about the factorial structure of TIE, its relations to socio-demographic variables, and its influence on intellectual functioning in old age. In the present study, data of 364 adults (65-81 years) from the Zurich Longitudinal Study on Cognitive Aging (ZULU) were used to investigate the factorial structure of TIE and to examine the hypothesis that TIE is associated more strongly with crystallized intelligence than with fluid intelligence in old age. A measurement model of a second order factor based on a structure of four correlated first order factors (Reading, Problem Solving, Abstract Thinking, and Intellectual Curiosity) evinced an excellent fit. After controlling for age, sex, and formal education, TIE was more strongly associated with crystallized intelligence than with fluid intelligence, comparable to results in younger persons. More detailed analyses showed that this association is mostly defined via Reading and Intellectual Curiosity.     

Typical Intellectual Engagement and Cognition in Old Age

ABSTRACT

Typical Intellectual Engagement (TIE) comprises the preference to engage in cognitively demanding activities and has been proposed as a potential explanatory variable of individual differences in cognitive abilities. Little is known, however, about the factorial structure of TIE, its relations to socio-demographic variables, and its influence on intellectual functioning in old age. In the present study, data of 364 adults (65–81 years) from the Zurich Longitudinal Study on Cognitive Aging (ZULU) were used to investigate the factorial structure of TIE and to examine the hypothesis that TIE is associated more strongly with crystallized intelligence than with fluid intelligence in old age. A measurement model of a second order factor based on a structure of four correlated first order factors (Reading, Problem Solving, Abstract Thinking, and Intellectual Curiosity) evinced an excellent fit. After controlling for age, sex, and formal education, TIE was more strongly associated with crystallized intelligence than with fluid intelligence, comparable to results in younger persons. More detailed analyses showed that this association is mostly defined via Reading and Intellectual Curiosity.     

Age changes in processing speed as a leading indicator of cognitive aging

Bivariate dual change score models were applied to longitudinal data from the Swedish Adoption/Twin Study of Aging to compare the dynamic predictions of 2-component theories of intelligence and the processing speed theory of cognitive aging. Data from up to 5 measurement occasions covering a 16-year period were available from 806 participants ranging in age from 50 to 88 years at the first measurement wave. Factors were generated to tap 4 general cognitive domains: verbal ability, spatial ability, memory, and processing speed. Model fitting indicated no dynamic relationship between verbal and spatial factors, providing no support for the hypothesis that age changes in fluid abilities drive age changes in crystallized abilities. The results suggest that, as predicted by the processing speed theory of cognitive aging, processing speed is a leading indicator of age changes in memory and spatial ability, but not verbal ability.     

Social support,physical functioning,and cognitive functioning among older African American adults

ABSTRACT

Social support and functional ability are related to a number of outcomes in later life among African Americans, including cognitive performance. This study examined how providing and receiving social support was related to fluid and crystallized cognitive abilities among aging African American adults after accounting for functional limitations, age, education, sex, income, and self-reported health. Data from 602 African American adults (M?=?69.08, SD?=?9.74; 25% male) were analyzed using latent variable modeling. Fluid ability was a second-order factor indicated by measures that assessed verbal memory, working memory, perceptual speed, and inductive reasoning. Crystallized ability was a first-order factor indicated by three measures that assessed vocabulary (Shipley Verbal Meaning Test and parts A and B of the ETS Vocabulary Test). Results indicated that the receipt of social support was negatively related to both fluid and crystallized abilities, while the provision of support was positively related to fluid and crystallized ability. Follow-up tests found that the receipt of support was more strongly related to fluid ability than crystallized ability. There was no significant difference regarding the relationship of provision of support with fluid ability compared to crystallized ability. Results discuss the importance of considering the social context of older adults when examining cognitive ability.     

Vision and intelligence at age 83 in the Lothian Birth Cohort 1921

The extent to which visual function, measured as near and distant visual acuity and contrast sensitivity, is correlated with concurrently measured cognitive function and prior intellectual ability was investigated in a narrow age range group known as the Lothian Birth Cohort of 1921 (LBC1921). Participants were aged ~ 83 years at the time of testing (N = 321). A well-fitting structural equation model highlighted a significant contribution of a latent visual trait to a general fluid intelligence factor in old age, independent of the contribution from childhood intelligence. Additionally, childhood intelligence made a significant contribution to the general visual factor in old age. However, the model fitted equally well when the fluid intelligence factor is assumed to be a cause of the visual function latent trait, in which case childhood intelligence does not significantly influence vision in old age. We discuss these results with respect to four possible mechanisms by which vision and cognition can come to be correlated over the lifecourse.     

The impact of childhood intelligence on later life: following up the Scottish mental surveys of 1932 and 1947

The Scottish Mental Surveys of 1932 and 1947 collected valid IQ-type test scores for almost everyone born in 1921 and 1936 and attending school on June 1, 1932 (N=89,498) and June 4, 1947 (N=70,805). These surveys are described. This research, using the surveys' data, examined (a) the stability of intelligence differences across the life span, (b) the determinants of cognitive change from childhood to old age, and (c) the impact of childhood intelligence on survival and health in old age. Surviving participants of the Scottish Mental Surveys were tested, and the surveys' data were linked with public and health records. Novel findings on the stability of IQ scores from age 11 to age 80; sex differences in cognitive aging; the dedifferentiation hypothesis of cognitive aging; and the effect of childhood IQ on all-cause and specific mortality, morbidity, and frailty in old age are presented.     

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。     

Contribution de la neuropsychologie développementale à l'étude des sujets à haut potentiel : une revue de questions

Developmental neuropsychology studies cognitive development in relation with brain maturation and cerebral plasticity. Some authors have reported physiological correlates of intellectual precocity with the purpose of demonstrating neural basis of intelligence. A part of the literature also reports various cognitive profile and specific talents in information processing in the clinical population of gifted children. Thus, the study of exceptional performances may contribute to our knowledge of functional brain organization taking into consideration individual differences.     

Can fluid intelligence be reduced to ‘simple’ short-term storage?

Much is written regarding the associations between human intelligence and cognition. However, it is unusual to find comprehensive studies. Here twenty four measures tapping eight cognitive abilities and skills are considered for assessing a sample of one hundred and eighty five young adults. The simultaneous relationships among fluid, crystallized, and spatial intelligence, along with short-term memory, working memory capacity, executive updating, attention, and processing speed are analyzed using a latent-variable approach. The key findings show that (a) short-term storage, working memory, and updating are hardly distinguishable, and (b) fluid intelligence is near-perfectly correlated with these three cognitive functions. It is concluded that this nuclear intelligence component can be largely identified with basic and general short-term storage processes, namely, encoding, maintenance, and retrieval.     

Reserve capacity of the elderly in aging-sensitive tests of fluid intelligence: replication and extension

Fluid intelligence belongs to that cluster of intellectual abilities evincing aging loss. To examine further the range of intellectual reserve available to aging individuals and the question of replicability in a new cultural and laboratory setting, 204 healthy older adults (mean age = 72 years; range = 60-86) participated in a short-term longitudinal training study. For experimental subjects, 10 sessions consisted of cognitive training involving two subability tests (Figural Relations, Induction) of fluid intelligence. The pattern of outcomes replicates and expands on earlier studies. Older adults have the reserve to evince substantial increases in levels of performance in fluid intelligence tests. Transfer of training, however, is narrow in scope. Training also increases accuracy of performance and the ability to solve more difficult test items. Difficulty level was estimated in a separate study, with a comparable sample of N = 112 elderly adults. Future research is suggested to examine whether intellectual reserve extends to near-maximum levels of performance.     

Une redéfinition des relations entre la personnalité « Ouverte à l’expérience » et l’intelligence

Previous investigations of the relations between the Big Five personality traits and cognitive abilities have consistently supported that higher levels of openness to experience are associated with higher levels of crystallized abilities or knowledge. However, consistent with the idea that crystallized abilities are the product of the exercise of fluid abilities in the past, a moderately strong correlation between both types of abilities is generally found. Then, the first purpose of the current project was to examine the role of fluid abilities in the relation between openness to experience and crystallized abilities. It aimed at determining whether the relation of openness to crystallized abilities was still significant after controlling for the specific contribution of fluid intelligence to crystallized abilities; or conversely, whether this relation was explained by the relation of openness to fluid intelligence. The second purpose was to determine if the relation of openness to experience to both fluid and crystallized abilities varied as a function of age. The possibility that openness to experience differentially contributes to the variance in fluid and crystallized abilities as a function of age was examined. One hundred and sixty-four participants, aged 18 to 96, completed the openness to experience scale (French version of the IPIP, Goldberg, 1999. Personality psychology in Europe), in addition to several tests of fluid and crystallized abilities. After controlling for the variance associated with fluid abilities in crystallized abilities, Openness to experience was not related to crystallized abilities anymore. Moreover, the contribution of the personality trait of Openness to the variation in fluid and crystallized intelligences was similar at different ages in adulthood. Several possible interpretations and their respective implications are discussed. First, people more open may exercise fluid abilities more than people who are less open, and then increase the efficiency of these abilities. Second, fluid abilities may influence the development of the personality trait of openness to experience, that is people's tendency to seek out for novelty and curiosity. And third, the openness to experience scale may only reflect people's self-assessments of their abilities, such as a self-assessed intelligence construct. In any case, our results strongly suggest that the openness-cognition relation reflects something different from a relation between activity and knowledge acquisition.     

Aging, attention, and intelligence

The aims of this study were (a) to find out if attentional ability factors that are separate from the well-established ability factors (e.g., fluid intelligence, crystallized intelligence, and short-term acquisition and retrieval function) can be identified, and (b) to establish, through the use of part correlations, whether attentional abilities play a role in the changes in fluid and crystallized intelligence that occur with increasing age. A battery of 36 tests (19 psychometric tests and 17 measures of attentional processes) were given to 100 people. 20 of whom were in each age decade between 20 and 70. Results indicated that three attentional factors--Search, Concentration, and Attentional Flexibility--exist at the primary-ability level and that all three define fluid intelligence at the second-order level. Results also indicate that the decline in fluid intelligence with increasing age disappears if attentional factors are parted-out. Similarly, the increase in crystallized intelligence with increasing age becomes even greater if one controls for attentional processes. I conclude that changes in attentional processes play an important part in changes in human intelligence with age.     

Training research in aging on the fluid ability of inductive reasoning

The modifiability of older adults' performance on Induction tasks was examined through cognitive training. The posttraining performance of 52 older adults ($\text{X}\text{age = 70.3}\text{years}$) was assessed with regard to a transfer-of-training paradigm and maintenance of training effects at three posttests (one week, one month, six months). A pattern of differential training transfer across the posttest battery of fluid and crystallized intelligence measures was predicted, with the largest training effects expected for near transfer (Induction) measures. The predicted pattern of training transfer was obtained at one-week and one-month posttests, with significant training effects to the nearest Induction measure. Large retest (practice) effects across posttests also occurred for training and control groups. This research contributes to the position that modifiability of intellectual performance through cognitive intervention extends across the adult life span.     

Factors predicting the use of technology: findings from the Center for Research and Education on Aging and Technology Enhancement (CREATE)

The successful adoption of technology is becoming increasingly important to functional independence. The present article reports findings from the Center for Research and Education on Aging and Technology Enhancement (CREATE) on the use of technology among community-dwelling adults. The sample included 1,204 individuals ranging in age from 18-91 years. All participants completed a battery that included measures of demographic characteristics, self-rated health, experience with technology, attitudes toward computers, and component cognitive abilities. Findings indicate that the older adults were less likely than younger adults to use technology in general, computers, and the World Wide Web. The results also indicate that computer anxiety, fluid intelligence, and crystallized intelligence were important predictors of the use of technology. The relationship between age and adoption of technology was mediated by cognitive abilities, computer self-efficacy, and computer anxiety. These findings are discussed in terms of training strategies to promote technology adoption.     

Lifespan development of stimulus-response conflict cost: similarities and differences between maturation and senescence

Age gradient of the mechanism of stimulus-response conflict cost was investigated in a population-based representative sample of 291 individuals, covering the age range from 6 to 89 years. Stimulus-response conflict cost, indicated by the amount of additional processing time required when there is a conflict between stimulus and response options, follows a U-shaped function across the lifespan. Lifespan age gradient of conflict cost parallels closely those of processing fluctuation and fluid intelligence. Individuals at both ends of the lifespan displayed a greater amount of processing fluctuation and at the same time a larger amount of conflict cost and a lower level of fluid intelligence. After controlling for chronological age and baseline processing speed, conflict cost continues to correlate significantly with fluid intelligence in adulthood and old age and with processing fluctuation in old age. The relation between processing fluctuation and conflict cost in old age lends further support for the neuromodulation of neuronal noise theory of cognitive aging as well as for theories of dopaminergic modulation of conflict monitoring.     

Single tests,competing tasks and their relationship to the broad factors of intelligence

This paper presents the results of three studies in which scores obtained on single and competing tests were correlated with the composites representing fluid intelligence, crystallized intelligence, and the short-term acquisition and retrieval function. The results indicate that competing tasks have higher correlations with intelligence than single tests. Since in two studies of this paper no decrements in performance were observed on the competing as compared with the single task, the concept of limited central processing capacity cannot account for individual differences in performance of these cognitive tasks. It is suggested that the concept of efficient processing of information, perhaps efficient encoding, may be the basis for individual differences in cognitive abilities.     

Concepts of intellect in relation to learning and adult development

This article is a summary and integration of results from studies of the organization and development of human abilities. Several kinds of results are interpreted as converging toward support of theories stipulating a hierarchy of intellectual functions. Near the top of this hierarchy, most related to intelligence as this is usually conceived, are the two broad sets of abilities known as fluid intelligence (Gf) and crystallized intelligence (Gc). The major focus of the review is on the decline of Gf through the “vital years of adulthood,” from 20 to 60 years of age. Major conclusions are:1. Sensory detector functions, near the bottom of the hierarchy of intellectual capacities, decline with development through the vital years, but this kind of decline is not responsible for aging decline of the major features of fluid intelligence: keenness of sensory function is not of the sine qua non of mature expressions of human intelligence.2. Memory abilities are somewhat higher in the hierarchy of intellectual functions, and thus are more strongly related to intelligence, than are sensory detectors. With increase in time interval over which retention is required, there is increase in the relationship of memory to Gf and to decline of Gf over the vital years. Accompanying this increase is an increase in the extent to which memory is dependent upon adequacy of organization at the stage of encoding. This, in turn, reflects the adequacy of eduction of relations and correlates, which is an essential feature of Gf.3. To the extent that very short-term memory is implicated in fluid intelligence, and the decline of this, it is intimately related to either a capacity or inclination to maintain close attention under conditions of high demand for attention.4. The speed with which one obtains correct answers to difficult problems is not closely related to the number of correct answers obtained when all subjects attempt all items in fluid intelligence tests, but clerical/perpetual speed, as indicated in tasks of quickly finding a particular symbol among others or tasks of making same/different judgments, is related to aging decline of Gf. As with short-term memory, this form of intellectual speediness appears to be closely related to capacities (or inclinations) for maintaining attention, dividing attention, and holding things in mind while doing other things.5. Crystallized intelligence probably increases over the vital years. This reflects dynamic restructuring of knowledge systems. It appears that there is not only an aging increase in knowledge but also an increase in the accessibility of information, a result being that humans become more creative (in one sense) as age increases through the vital years.6. Results from multivariate cross-sectional studies of intelligence are seen to be consistent with comparable results obtained with other kinds of research strategies.