Examining Preschool Cognitive Abilities Using a CHC Framework

Although there has been a substantial growth in the number of published studies examining tests of cognitive abilities and using contemporary theories of cognitive abilities, to date none have done so with preschool cognitive tests. In this study the relation between cognitive ability measures for young children and Cattell-Horn-Carroll (CHC) theory is examined. Tests and subtests from the Differential Ability Scales: Upper Preschool Level and the Woodcock-Johnson Tests of Cognitive Ability-Revised with a sample of 158 children between 4 and 5 years of age were used in a series of joint factor analyses. Although a series of models were explored, the model representative of the CHC theory of cognitive abilities was best supported by the data. This provides evidence for a greater differentiation of young children's cognitive abilities than are typically interpreted. Results are discussed with regard to understanding the link between contemporary theories of intelligence and young children's cognitive abilities, as well as implications for intellectual assessment practices with young children.     

“To g or not to g?” — Analysis of the dimensional structure of a cognitive abilities’ battery

Over the past century there has been an extensive debate in Psychology over whether intelligence structure is best represented through a single general ability, multiple specific abilities, or a hierarchical structure of abilities. This study aims at contributing to this debate through an analysis of the dimensional structure of a cognitive abilities’ battery aiming to evaluate, in combination, differentiated cognitive processes of increasing complexity (comprehension, reasoning, and problem solving) through items of different contents (verbal, numerical, and spatial). A Portuguese representative sample of 2546 adolescents enrolled in secondary education participated in the study. Confirmatory factor analyses were carried out and the results showed that: (1) the hierarchical model is the only presenting an acceptable fit to the data (RMSEA = .07; CFI = .96; TLI = .92), (2) the existence of specific factors cannot be neglected, and (3) contents of the subtests assume relevance to explain the levels of adolescents’ cognitive performance. These results are discussed taking into account the contribution of school experience for the development and differentiation of adolescents’ cognitive abilities.     

Comparison of age and time-to-death in the dedifferentiation of late-life cognitive abilities

The dedifferentiation hypothesis proposes that specific cognitive abilities become more highly associated with general ability in old age as a result of increasing biological constraints on fluid intelligence. There is limited evidence for the hypothesis, and research has not tended to clearly distinguish age dedifferentiation from ability differentiation and other age-related phenomena. The present study examined age dedifferentiation using a structural equation model that controlled for ability differentiation, along with linear and quadratic effects of age. Time-to-death was examined as an alternative time metric to chronological age, as it may better represent biological constraints. The Canberra Longitudinal Study community-based cohort, consisting of 896 Australian adults aged 70 and over, provided data from 687 decedents who were followed for up to 17 years. Results indicated little support for the age dedifferentiation hypothesis, with only two of seven cognitive tests showing significant age dedifferentiation. The time-to-death metric showed more evidence of dedifferentiation, with four of the seven tests exhibiting dedifferentiation. However, after excluding participants with possible cognitive impairment, all of the dedifferentiation effects were attenuated to nonsignificance. Age dedifferentiation effects may therefore reflect dementia and other mortality-related pathology rather than being an inevitable outcome of advanced age. Alternative developmental theories for cognitive function must better account for the diversity of late-life abilities and pathology.     

智力结构的分化假设

该文探讨了智力结构随能力、年龄等个体差异而变化的可能性。认知分化假设认为,能力水平更高的人有“更多”的智力,其智力结构中g因素的作用随IQ水平的增加而递减。年龄分化假设指出,从童年期到青年早期,g因素在认知能力中的作用随年龄的增加而减小;相反,从青年早期到成年晚期,g因素的作用递增,智力结构中其他因素的数量和重要性则递减。该领域未来的研究应当解决测量和评估工具的问题,扩大被试的能力水平和年龄范围     

Does the level at which cognitive change occurs change with age?

Increased age in adulthood is associated with systematically more negative cognitive change, but relatively little is known about the nature of change at different ages. The present study capitalized on the hierarchical structure of cognitive abilities to investigate possible age differences in the level at which change operates. Reductions in the longitudinal associations between test scores when across-time relations were specified at different levels in the hierarchical structure were used to infer contributions to change from the level of abilities and from the level of a general factor. Although the pattern of influences varied across different cognitive abilities, the results revealed little or no age differences in the relative contributions to change from different levels in the hierarchy.     

Relations between Preschool Children’s Fine Motor Skills and General Cognitive Abilities

ABSTRACT

An increasing number of findings suggest that cognition is grounded in sensorimotor experiences. Research suggests that fine motor skills (FMS) link to cognitive abilities. Existing studies, however, lack conceptual and methodological differentiation regarding FMS and little is known about the directional nature of links. In study 1, we measured three types of FMS, namely dexterity, grapho-motor skill, speed-dominated FMS in a sample of preschool children (n = 78) aged 4.42 years, and analyzed their links with nonverbal reasoning and general knowledge. Factor analyses verified the existence of these three distinct subsets of FMS. A unique link was found for dexterity and reasoning after controlling for age, attention and processing speed. In study 2, using a cross-lagged-panel design with two measurement points one year apart in preschool (n = 84), a cross-lagged link from four-year-old children’s dexterity to their reasoning skills at age five was demonstrated. Findings support the idea of FMS being involved in the development of cognitive abilities.     

Testing specific cognitive abilities by telephone and mail

The two goals of this research were to develop a brief battery of tests of specific cognitive abilities that can be administered via telephone to adolescents and to assess the psychometric properties of the battery. In a sample of 212 adolescents from 10 to 15 years of age, factor analyses supported the hypothesized structure of verbal, spatial, perceptual speed, and memory abilities, with three tests intended to mark each factor. For a subsample of 62 subjects, retest correlations were .81, .73, .82, and .57, respectively, for the four specific cognitive abilities; scores from telephone testing and face-to-face testing correlated near the reliabilities of the telephone tests. Recommendations are made for shortening the 60-min battery to 35 min by using only two tests to mark each factor.     

Task control and cognitive abilities of self and spouse in collaboration in middle-aged and older couples

Collaborative problem solving may be used by older couples to optimize cognitive functioning, with some suggestion that older couples exhibit greater collaborative expertise. The study explored age differences in 2 aspects of collaborative expertise: spouses' knowledge of their own and their spouse's cognitive abilities and the ability to fit task control to these cognitive abilities. The participants were 300 middle-aged and older couples who completed a hypothetical errand task. The interactions were coded for control asserted by husbands and wives. Fluid intelligence was assessed, and spouses rated their own and their spouse's cognitive abilities. The results revealed no age differences in couple expertise, either in the ability to predict their own and their spouse's cognitive abilities or in the ability to fit task control to abilities. However, gender differences were found. Women fit task control to their own and their spouse's cognitive abilities; men only fit task control to their spouse's cognitive abilities. For women only, the fit between control and abilities was associated with better performance. The results indicate no age differences in couple expertise but point to gender as a factor in optimal collaboration.     

A parent-offspring adoption study of cognitive abilities in early childhood

Do cognitive abilities in early childhood relate genetically and/or environmentally to isomorphic abilities in adulthood? Are specific cognitive abilities diffentiated in early childhood in terms of their prediction of adult cognitive abilities? The present study, the first behavioral genetic analysis of specific cognitive abilities in early childhood, explored these questions using parent-offspring data for 186 adopted children and 151 nonadopted children tested in the longitudinal Colorado Adoption Project at 3 years of age and 162 adopted children and 138 nonadopted children tested at 4 years. The children's Stanford-Binet IQ and scores for four specific cognitive abilities (verbal, spatial, perceptual speed, and memory) were correlated with corresponding measures for their parents—the biological and adoptive parents of the adopted children and the natural parents of the nonadopted children. Significant correlations were found between biological mothers' IQ and the IQ of their adopted away offspring at 3 and 4 years of age, suggesting genetic influence for IQ. However, specific cognitive abilities yielded no significant correlations between biological mothers and their adopted-away offspring. These results suggest that substantial genetic continuity exists for IQ from early childhood to adulthood, but not for specific cognitive abilities.     

Exploring Factor Model Parameters across Continuous Variables with Local Structural Equation Models

Using an empirical data set, we investigated variation in factor model parameters across a continuous moderator variable and demonstrated three modeling approaches: multiple-group mean and covariance structure (MGMCS) analyses, local structural equation modeling (LSEM), and moderated factor analysis (MFA). We focused on how to study variation in factor model parameters as a function of continuous variables such as age, socioeconomic status, ability levels, acculturation, and so forth. Specifically, we formalized the LSEM approach in detail as compared with previous work and investigated its statistical properties with an analytical derivation and a simulation study. We also provide code for the easy implementation of LSEM. The illustration of methods was based on cross-sectional cognitive ability data from individuals ranging in age from 4 to 23 years. Variations in factor loadings across age were examined with regard to the age differentiation hypothesis. LSEM and MFA converged with respect to the conclusions. When there was a broad age range within groups and varying relations between the indicator variables and the common factor across age, MGMCS produced distorted parameter estimates. We discuss the pros of LSEM compared with MFA and recommend using the two tools as complementary approaches for investigating moderation in factor model parameters.     

Relationships Among Education,Age, and Cognitive Functioning in Older African Americans: The Impact of Desegregation

The current study sought to examine whether there were differences in the structure of specific cognitive abilities and their association with age and education in a sample of African American elders with two different early educational experiences. The study was conducted with a sample of 197 community dwelling older adults ranging in age from 50 to 79 years (mean age = 61.50 years, SD = 7.30 years). The sample included 79 individuals who attended a desegregated school at anytime during their formal education, while 118 participants completed their schooling without ever attending a desegregated school. Major results included: (1) typical patterns among cognitive abilities and age as well as years of education were found in the full sample of participants; (2) the pattern of age differences in cognition differed between the two groups. Regarding the latter, the desegregated sample exhibited significant negative age differences for some cognitive abilities, while the segregated group did not. Discussion focuses on the importance of considering the nature of the educational experience when examining cognitive aging in African American elders.     

The differentiation hypothesis and the Flynn effect

Many studies have shown that IQs have been increasing over the last half century. These increases have come to be known as "the Flynn effect". The "Flynn effect" represents a difference on ability-level between groups of the same age but different cohort. The ability-level differentiation hypothesis represents a difference on the relevance of cognitive factors between groups of high and low ability. Hence, it should be possible to imitate the ability-level differentiation effect by comparing groups of the same age but different cohort. The indifferentiation hypothesis represents no differences on the relevance of cognitive abilities in all age groups within the same cohort. The aim of the present study is to test the relationships between these phenomena. For this purpose we analyzed the American standardisation samples of the WISC, WISC-R and WISC-III. Results support the link between the Flynn effect and the differentiation hypothesis. Also, reported evidence replicate previous findings supporting the indifferentiation hypothesis. Implications for the assessment of the intelligence are discussed.     

Associations between cortical thickness and general intelligence in children,adolescents and young adults

Neuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throughout both brain hemispheres. In this study, we performed a cortical thickness mapping analysis on data from 182 healthy typically developing males and females ages 9 to 24 years to identify correlates of general intelligence (g) scores. To determine if these correlates also mediate associations of specific cognitive abilities with cortical thickness, we regressed specific cognitive test scores on g scores and analyzed the residuals with respect to cortical thickness. The effect of age on the association between cortical thickness and intelligence was examined. We found a widely distributed pattern of positive associations between cortical thickness and g scores, as derived from the first unrotated principal factor of a factor analysis of Wechsler Abbreviated Scale of Intelligence (WASI) subtest scores. After WASI specific cognitive subtest scores were regressed on g factor scores, the residual score variances did not correlate significantly with cortical thickness in the full sample with age covaried. When participants were grouped at the age median, significant positive associations of cortical thickness were obtained in the older group for g-residualized scores on Block Design (a measure of visual-motor integrative processing) while significant negative associations of cortical thickness were observed in the younger group for g-residualized Vocabulary scores. These results regarding correlates of general intelligence are concordant with the existing literature, while the findings from younger versus older subgroups have implications for future research on brain structural correlates of specific cognitive abilities, as well as the cognitive domain specificity of behavioral performance correlates of normative gray matter thinning during adolescence.     

Quantitative genetic analysis of latent growth curve models of cognitive abilities in adulthood

Though many cognitive abilities exhibit marked decline over the adult years, individual differences in rates of change have been observed. In the current study, biometrical latent growth models were used to examine sources of variability for ability level (intercept) and change (linear and quadratic effects) for verbal, fluid, memory, and perceptual speed abilities in the Swedish Adoption/Twin Study of Aging. Genetic influences were more important for ability level at age 65 and quadratic change than for linear slope at age 65. Expected variance components indicated decreasing genetic and increasing nonshared environmental variation over age. Exceptions included one verbal and two memory measures that showed increasing genetic and nonshared environmental variance. The present findings provide support for theories of the increasing influence of the environment with age on cognitive abilities.     

Personality-cognition relations across adulthood

Although an increasing number of studies have investigated relations between dimensions of personality and level of cognitive functioning, the research results have been somewhat inconsistent. Furthermore, relatively little is known about whether the personality-cognition relations vary as a function of age in adulthood. The current project examined these issues with data from a sample of 2,317 adults between 18 and 96 years of age who each completed a personality inventory and performed a broad battery of cognitive tests. The results revealed strong relations of the personality trait of Openness with several distinct cognitive abilities and smaller relations of other personality traits with specific cognitive abilities. Comparisons across different age groups indicated that the personality-cognition relations were both qualitatively and quantitatively similar across the adult years.     

Intelligence indexes generalist genes for cognitive abilities

Twin research has supported the concept of intelligence (general cognitive ability, g) by showing that genetic correlations between diverse tests of verbal and nonverbal cognitive abilities are greater than 0.50. That is, most of the genes that affect cognitive abilities are highly pleiotropic in the sense that genes that affect one cognitive ability affect all cognitive abilities. The impact of this finding may have been blunted because it depends on the validity of the twin method. Although the assumptions of the twin method have survived indirect tests, it is now possible to test findings from the twin method directly using DNA alone in samples of unrelated individuals, without the assumptions of the twin method. We applied this DNA method, implemented in a software package called Genome-wide Complex Trait Analysis (GCTA), to estimate genetic variance and covariance for two verbal tests and two nonverbal tests using 1.7 million DNA markers genotyped on 2500 unrelated children at age 12; 1900 children also had cognitive data and DNA at age 7. Because each of these individuals is one member of a twin pair, we were able to compare GCTA estimates directly to twin study estimates using the same measures in the same sample. At age 12, GCTA confirmed the results of twin research in showing substantial genetic covariance between verbal and nonverbal composites. The GCTA genetic correlation at age 12 was 1.0 (SE = 0.32), not significantly different from the twin study estimate of 0.60 (SE = 0.09). At age 7, the genetic correlations were 0.31 (SE = 0.32) from GCTA and 0.71 (SE = 0.15).from twin analysis. The results from the larger sample and stronger measures at age 12 confirm the twin study results that the genetic architecture of intelligence is driven by pleiotropic effects on diverse cognitive abilities. However, the results at age 7 and the large standard errors of GCTA bivariate genetic correlations suggest the need for further research with larger samples.     

Testing the age related differentiation hypothesis through the Wechsler’s scales

According to the age differentiation hypothesis (ADH), g becomes increasingly invested in specific abilities with age: with increasing age, g should account for a decreasing proportion of the variance in any particular cognitive test. However, there is no conclusive evidence concerning this important topic. Data from the Italian, Spanish, and American standardisation samples of the WPPSI and the WISC-R were analysed in the present study for testing the ADH. No changes in the proportion of variance associated with g in the 4–16 age range were found. This pattern does not change depending on the country. Therefore, the ADH is rejected: g seems to be very stable across age, and, thus, it seems to be an equally important component of intelligence test performance from early childhood to late adolescence.     

Does it all go together when it goes? The nineteenth Bartlett memorial lecture

As groups of people age, the differences in the cognitive abilities of the most and least able become more extreme. This increase in between-individual variance is accompanied by an increase in within-individual variance: the difference between individuals' levels of performance on their best and least well retained skills. The implications of increasing between-individual variance are discussed in terms of the range of different factors that may affect cognitive ageing. Increases in within-individual variance are discussed in terms of differences betweeen “fluid” and “crystallized” abilities. The usefulness of this distinction and its functional implications are questioned. The hypothesis that age-related declines in “fluid” abilities are best modelled in terms of declines in a single factor is evaluated. Evidence is presented of disparate rates of decline, even of “fluid” cognitive abilities, such as performance on IQ tests, ability on information-processing tasks, and efficiency on memory tasks. Data from large-scale cross-sectional studies suggests that cognitive skills do not “all go together when they go”, but that there may, rather, be characteristic patterns, or syndromes, of cognitive ageing.     

Confirmatory Factor Analysis and Multidimensional Scaling for Construct Validation of Cognitive Abilities

Although factor analysis is the most commonly-used method for examining the structure of cognitive variable interrelations, multidimensional scaling (MDS) can provide visual representations highlighting the continuous nature of interrelations among variables. Using data (N = 8,813; ages 17-97 years) aggregated across 38 separate studies, MDS was applied to 16 cognitive variables representative of five well-established cognitive abilities. Parallel to confirmatory factor analytic solutions, and consistent with past MDS applications, the results for young (18-39 years), middle (40-65 years), and old (66-97 years) adult age groups consistently revealed a two-dimensional radex disk, with variables from fluid reasoning tests located at the center. Using a new method, target measures hypothesized to reflect three aspects of cognitive control (updating, storage-plus-processing, and executive functioning) were projected onto the radex disk. Parallel to factor analytic results, these variables were also found to be centrally located in the cognitive ability space. The advantages and limitations of the radex representation are discussed.