Gray matter correlates of fluid,crystallized, and spatial intelligence: Testing the P-FIT model

The parieto-frontal integration theory (P-FIT) nominates several areas distributed throughout the brain as relevant for intelligence. This theory was derived from previously published studies using a variety of both imaging methods and tests of cognitive ability. Here we test this theory in a new sample of young healthy adults (N = 100) using a psychometric battery tapping fluid, crystallized, and spatial intelligence factors. High resolution structural MRI scans (3T) were obtained and analyzed with Voxel-based Morphometry (VBM). The main findings are consistent with the P-FIT, supporting the view that general intelligence (g) involves multiple cortical areas throughout the brain. Key regions include the dorsolateral prefrontal cortex, Broca's and Wernicke's areas, the somato-sensory association cortex, and the visual association cortex. Further, estimates of crystallized and spatial intelligence with g statistically removed, still share several brain areas with general intelligence, but also show some degree of uniqueness.     

Ability factors and cognitive processes

Several measures of the speed of information processing were related to ability factors derived from the Cattell-Horn theory of fluid and crystallized intelligence. Ninety-one college students took a battery of paper and pencil tests designed to measure four ability factors: fluid intelligence (Gf), crystallized intelligence (Gc), spatial visualization (Gv), and clerical perceptual speed (CPS). They also performed paper and pencil and computerized versions of three information processing tasks: mental rotations, letter matching, and sentence verification. Correlations among the ability measures, among the information processing measures, and between the two domains were analyzed using confirmatory factor analysis. The four ability factors were found to be largely independent in this college population. Speed of letter-matching and sentence verification were highly correlated, but neither was related to speed of mental rotation. Mental rotation speed was strongly correlated with Gv; letter matching speed was correlated with CPS; and sentence verification speed was correlated with both Gc and CPS.     

Transformations in the couplings among intellectual abilities and constituent cognitive processes across the life span

Abstract— Two-component theories of intellectual development over the life span postulate that fluid abilities develop earlier during child development and decline earlier during aging than crystallized abilities do, and that fluid abilities support or constrain the acquisition and expression of crystallized abilities. Thus, maturation and senescence compress the structure of intelligence by imposing age-specific constraints upon its constituent processes. Hence, the couplings among different intellectual abilities and cognitive processes are expected to be strong in childhood and old age. Findings from a population-based study of 291 individuals aged 6 to 89 years support these predictions. Furthermore, processing robustness, a frequently overlooked aspect of processing, predicted fluid intelligence beyond processing speed in old age but not in childhood, suggesting that the causes of more compressed functional organization of intelligence differ between maturation and senescence. Research on developmental changes in functional brain circuitry may profit from explicitly recognizing transformations in the organization of intellectual abilities and their underlying cognitive processes across the life span.     

Working memory and the attentional blink: Blink size is predicted by individual differences in operation span

The attentional blink (AB) is often attributed to resource limitations, but the nature of these resources is commonly underspecified. Recent observations rule out access to short-term memory or storage capacity as limiting factors, but operation bottlenecks are still an option. We considered the operation span of working memory (WM) as a possible factor and investigated the relationship between individual WM operation span (as measured by OSPAN), fluid intelligence (as measures by Raven’s SPM), and the size of the AB. WM operation span was negatively correlated with the AB, whereas fluid intelligence was associated with higher overall accuracy but not with AB magnitude. These results support the idea that individual processing limitations (with regard to either attentional allocation policies or the speed of global cortical integration processes) play a key role in the AB.     

Convergence between attention variables and factors of psychometric intelligence in older adults

The purpose of the present study was to examine the hypothesis that individual differences on measures of attention would converge with select factors of psychometric intelligence, especially fluid intelligence and short-term acquisition and retrieval. A sample of 83 elderly adults $\text{(}\text{X}\text{= 71}\text{years}\text{)}$ was administered a battery of 17 psychometric ability tests. Tests were selected to mark four psychometric ability factors (Cattell and Horn's dimensions of fluid and crystallized intelligence, short-term acquisition and retrieval, and perceptual speed). Also, seven tasks representing four aspects of attention—decoding processes, selective attention, attention switching, and concentration—were administered. A confirmatory factor analysis was conducted to examine the relationships among the four psychometric ability factors and 11 variables obtained from the attention tasks. Results were only partially consistent with the hypothesized pattern of convergence. Two attention measures had significant loadings on a fluid-type intelligence factor, and one had a marginally significant loading on a short-term memory factor. In general, the greatest convergence occured between attention variables and the ability factor of Perceptual Speed. Results were discussed with respect to previous research on psychometric abilities and cognitive processes, the theory of fluid-crystallized intelligence, and their implications for understanding intellectual aging.     

Typical intellectual engagement,Big Five personality traits,approaches to learning and cognitive ability predictors of academic performance

Background Both ability (measured by power tests) and non‐ability (measured by preference tests) individual difference measures predict academic school outcomes. These include fluid as well as crystalized intelligence, personality traits, and learning styles. This paper examines the incremental validity of five psychometric tests and the sex and age of pupils to predict their General Certificate in Secondary Education (GCSE) test results. Aims The aim was to determine how much variance ability and non‐ability tests can account for in predicting specific GCSE exam scores. Sample The sample comprised 212 British schoolchildren. Of these, 123 were females. Their mean age was 15.8 years (SD 0.98 years). Method Pupils completed three self‐report tests: the Neuroticism–Extroversion–Openness‐Five‐Factor Inventory (NEO‐FFI) which measures the ‘Big Five’ personality traits, ( Costa & McCrae, 1992 ); the Typical Intellectual Engagement Scale ( Goff & Ackerman, 1992 ) and a measure of learning style, the Study Process Questionnaire (SPQ; Biggs, 1987 ). They also completed two ability tests: the Wonderlic Personnel Test ( Wonderlic, 1992 ) a short measure of general intelligence and the General Knowledge Test ( Irving, Cammock, & Lynn, 2001 ) a measure of crystallized intelligence. Six months later they took their (10th grade) GCSE exams comprising four ‘core’ compulsory exams as well as a number of specific elective subjects. Results Correlational analysis suggested that intelligence was the best predictors of school results. Preference test measures accounted for relatively little variance. Regressions indicated that over 50% of the variance in school exams for English (Literature and Language) and Maths and Science combined could be accounted for by these individual difference factors. Conclusions Data from less than an hour's worth of testing pupils could predict school exam results 6 months later. These tests could, therefore, be used to reliably inform important decisions about how pupils are taught.     

Attentional WM is not necessarily specifically related with fluid intelligence: the case of smart children with ADHD symptoms

Executive functions and, in particular, Attentional (active) Working Memory (WM) have been associated with fluid intelligence. The association contrasts with the hypothesis that children with ADHD exhibit problems with WM tasks requiring controlled attention and may have a good fluid intelligence. This paper examines whether children who are intelligent but present ADHD symptoms fail in attentional WM tasks. The latter result would be problematic for theories assuming the generality of a strict relationship between intelligence and WM. To study these issues, a battery of tests was administered to a group of 58 children who all displayed symptoms of ADHD. All children were between the age of 8 and 11 years, and were described by their teachers as smart. Children were compared to a control group matched for age, schooling, and gender. The battery included a test of fluid intelligence (Raven’s Coloured Matrices), and a series of visuospatial WM tasks. Results showed that children with ADHD were high in intelligence but significantly lower than the controls in WM tasks requiring high attentional control, whereas there was no difference in WM tasks requiring low attentional control. Furthermore, only high attentional control WM tasks were significantly related to Raven’s performance in the control group, whereas all WM tasks were similarly related in the ADHD group. It is concluded that performance in high attentional control WM tasks may be related to fluid intelligence, but also to a specific control component that is independent of intelligence and is poor in children with ADHD.     

Latent growth curve analyses of accelerating decline in cognitive abilities in late adulthood

Latent growth models were applied to data from the Swedish Adoption/Twin Study of Aging to discover if the rate of change in cognitive performance increased from middle age to later adulthood. The sample included 590 participants aged 44 to 88 years at first measurement. Data were gathered at 2 follow-up occasions at intervals of 3 years. Cognitive ability was assessed through 11 tests that tapped crystallized, fluid, memory, and spatial abilities and perceptual speed. Results indicated stability for measures of crystallized ability, linear age changes for many cognitive abilities, and a significant acceleration in linear decline after age 65 for measures with a large speed component. Gender differences were found only in mean level, not in rate of decline.     

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.     

The Getting of Wisdom: Fluid Intelligence Does Not Drive Knowledge Acquisition

The investment hypothesis proposes that fluid intelligence drives the accumulation of crystallized intelligence, such that crystallized intelligence increases more substantially in individuals with high rather than low fluid intelligence. However, most investigations have been conducted on adolescent cohorts or in two-wave data sets. There are few longitudinal representative studies with which to observe the growth of intelligence in young adulthood. A large community representative sample of 20- to 24-year-olds was recruited in 1999 and followed in 2003 and 2007. The Spot-the-Word Test Version A, a lexical decision task, was used to assess crystallized intelligence. The Symbol–Digit Modalities Test, a test of perceptual speed, was used as a measure of fluid intelligence. Latent growth models were used to examine whether growth in fluid intelligence drives the acquisition of crystallized intelligence. Fluid and crystallized intelligence are coupled; crystallized intelligence accrues in the 20s, but the rate of increase of crystallized intelligence is not associated with the level of fluid intelligence. Although young adulthood is associated with “the getting of wisdom,” accelerated development of crystallized intelligence in those with high fluid intelligence was not observed. Hence, no support was found for the investment hypothesis.     

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.     

Relationship between Cattell’s 16PF and fluid and crystallized intelligence

The aim of the study was to explore the relationship between the five global factors and 16 dimensions of Cattell’s personality model and fluid and crystallized intelligence. A total of 105 third graders (45.7% males) of three high schools participated in the research. Fluid intelligence was measured by Raven’s Advanced Progressive Matrices and crystallized intelligence was measured by the Mill Hill Vocabulary Scale. Personality traits were measured by the Sixteen Personality Factor Questionnaire. Anxiety is correlated neither with fluid nor with crystallized intelligence. Extraversion and Self-Control are negatively correlated with fluid intelligence whereas Tough-Mindedness is positively correlated with it. Independence is positively correlated with crystallized intelligence and Tough-Mindedness is negatively correlated with it. Regression analysis reveals that all broad personality factors, except anxiety, are significant predictors of fluid intelligence. When combined together, these factors account for 25% of the variance of fluid intelligence scores. The regression model with crystallized intelligence as a criterion variable is not statistically significant. The study results are consistent with the Chamorro-Premuzic and Furnham’s (2005) two-level conceptual framework. Although using a different taxonomy of personality, the results are in accordance with the model’s presuppositions.     

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.     

Autobiographical and text recall in the elderly: An investigation of a processing resource deficit

This study examined different explanations of age-related impairments in recall of details from text and autobiographical events. An interpretation of Central Executive Capacity Deficit was supported and explored further. This suggests that details are more demanding of capacity than main points, and that ability to appropriately integrate details with context is likely to be impaired. An implication was that irrelevant and false information may occur, and this was supported in both autobiographical and text recall. The effects were then examined in relation to various measures of ability. The aim was to determine whether declining capacity (as indicated by “Fluid Intelligence” measures) predicted ability to recall in a detailed manner. The difficulty with details was predicted independently by chronological age and by measures of fluid (e.g. AH4 intelligence test) and the more crystallized verbal ability (Mill Hill vocabulary test). Only a measure of the specificity of autobiographical recall was predicted solely by measures of fluid intelligence. Decreased specificity was not a result of faster decay of memory for details, as there was little difference across the lifespan. The resource deficit appears to affect retrieval and appropriate implementation of detail. It was concluded that lower-ability elderly subjects have decreased Central Executive resources, which leads to poor (often inappropriate) integration of details with central thematic points, but that subjects' verbal ability, which does not decline with age, still has an important part to play.     

Metaphorically speaking: cognitive abilities and the production of figurative language

Figurative language is one of the most common expressions of creative behavior in everyday life. However, the cognitive mechanisms behind figures of speech such as metaphors remain largely unexplained. Recent evidence suggests that fluid and executive abilities are important to the generation of conventional and creative metaphors. The present study investigated whether several factors of the Cattell–Horn–Carroll model of intelligence contribute to generating these different types of metaphors. Specifically, the roles of fluid intelligence (Gf), crystallized intelligence (Gc), and broad retrieval ability (Gr) were explored. Participants completed a series of intelligence tests and were asked to produce conventional and creative metaphors. Structural equation modeling was used to assess the contribution of the different factors of intelligence to metaphor production. For creative metaphor, there were large effects of Gf (β = .45) and Gr (β = .52); for conventional metaphor, there was a moderate effect of Gc (β = .30). Creative and conventional metaphors thus appear to be anchored in different patterns of abilities: Creative metaphors rely more on executive processes, whereas conventional metaphors primarily draw from acquired vocabulary knowledge.     

The effect of training in categorization on free recall: Some implications for Jensen's two-level theory

The effect of training in categorization on free recall learning was investigated in order to clarify an issue relating to Jensen's two-level theory of ability, namely, whether training in categorizetion would eliminate the reported association between free recall of categorized lists and socioeconomic status (SES). The subjects were 132 children partitioned into three groups on the basis of SES and two ability tests measuring fluid and crystallized intelligence (Cattell, 1963). Half the children in each group underwent training in categorization, and half were allocated to a control condition. The results revealed an interaction between ability and training. Low SES children of high fluid intelligence benefitted from categorization training and improved substantially in free recall of a categorized list so as to equal the performance of middle SES children. In contrast, low SES children matched for crystallized intelligence but scoring low in fluid intelligence did not benefit from training. The same three groups of children also learned an uncategorized list. The results did not support Jensen's hypothesis that free recall of uncategorized lists is unrelated to intelligence and SES.     

Which is the real intelligence? A reply to Robinson (1999)

Robinson's ([Robinson, D.L. (1999). The ‘IQ’ factor: implications for intelligence theory and measurement. Personality and Individual Differences, 27, 715–735]) arguments that crystallized intelligence represents the “one valid intelligence factor” are disputed. It is argued that Robinson seriously underestimated the relevance of fluid abilities to “intelligence”, by using an inappropriate criterion for assessing the intelligence-saturation of cognitive ability variables. The relevance of fluid and crystallized abilities to popular, psychometric, and biological conceptions of intelligence is discussed, and the issue of age-related changes in fluid and crystallized intelligence is also addressed.     

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.     

Racial differences in intelligence: The importance of the executive system

The race-IQ controversy arose at a time when psychometric views of intelligence dominated. Little attention was paid to more process-oriented models in spite of the fact they provide alternative perspectives on the causes of individual differences in problem-solving. We hypothesized that much of the IQ spread commonly observed between black and white children can be attributed to differences in components of their executive systems, including the knowledge base, control processes, and metacognitive states. To test this possibility, black and white children who differed significantly on fluid and crystallized intelligence were tested on multiple tasks reflecting components of the executive systems as well as on perceptual efficiency tasks. Striking group differences were observed in metamemory, stragegy use, and general knowledge, but few reliable differences were found in perceptual efficiency. Regression analyses showed that different factors predicted fluid and crystallized intelligence, with metamemory predicting the latter but not the former. An implication of these findings has potential educational significance: training directed at executive skills, introduce at an early age, might elevate learning and problem-solving skills in black children, thereby reducing racial differences in crystallized intelligence.     

The status of the concept of intelligence

Psychometric studies have shown that “general intelligence” should be broken down into the ability to apply learned solutions to new problems (crystallized intelligence) and the ability to deal with novel intellectual problems (fluid intelligence). This distinction has been amplified upon by studies of individual differences in information processing. Crystallized intelligence depends on the problem-solving schema that people have acquired and upon their efficiency in accessing information in long-term memory. Fluid intelligence is associated with the ability to access and manage relatively large amounts of information in working memory. Measures of fluid and crystallized intelligence are important predictors of objectively measured workplace performance. Studies of actual and simulated workplaces have shown that this is largely due to differences in people's ability to manage information and the speed with which the details of a job can be grasped.