Dextroamphetamine and measures of intelligence

A sample of 320 male high school students was drawn on the basis of their neuroticism and extraversion scores from a population of 2500 students. By following a 4 × 4 randomized block design (replicated 20 times) an attempt was made to study the effects of dextroamphetamine on the test scores of fluid and crystallized intelligence of high school children. The study lends support to the hypothesis that the drug will have a differetial effect on the test scores of fluid and crystallized intelligence.     

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.     

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.     

An experimental analysis of dynamic hypotheses about cognitive abilities and achievement from childhood to early adulthood

This study examined the dynamics of cognitive abilities and academic achievement from childhood to early adulthood. Predictions about time-dependent "coupling" relations between cognition and achievement based on R. B. Cattell's (1971, 1987) investment hypothesis were evaluated using linear dynamic models applied to longitudinal data (N=672). Contrary to Cattell's hypothesis, a first set of findings indicated that fluid and crystallized abilities, as defined by the Woodcock-Johnson Psycho-Educational Battery-Revised (WJ-R; R. W. Woodcock & M. B. Johnson, 1989-1990), were not dynamically coupled with each other over time. A second set of findings provided support for the original predictions and indicated that fluid ability was a leading indicator of changes in achievement measures (i.e., quantitative ability and general academic knowledge). The findings of this study suggest that the dynamics of cognitive abilities and academic achievement follow a more complex pattern than that specified by Cattell's 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.     

Fluid insight moderates the relationship between psychoticism and crystallized intelligence

To elucidate potential relationships between personality and intelligence it is necessary to move beyond the ad hoc reporting of correlation coefficients and focus instead on testing deductions from well-established theories. To this end the present paper references Eysenck’s (1995) theoretical work linking the dimension of psychoticism to both psychosis and creative genius. Drawing on this theory it was argued that the relationship between psychoticism and crystallized ability will be conditional on the level of fluid intelligence. Participants (N = 100) completed the Eysenck Personality Questionnaire-Revised (EPQ-R) and the Kaufman Brief Intelligence Test (K-BIT). Moderated multiple regression revealed a significant interaction effect. Crystallized ability (K-BIT vocabulary) was negatively related to psychoticism at low levels of fluid ability (K-BIT matrices) and positively related to psychoticism at high levels of fluid ability. These findings highlight the potential importance of psychoticism within GfGc investment theory.     

Working memory and fluid intelligence in young children

The present study investigates how working memory and fluid intelligence are related in young children and how these links develop over time. The major aim is to determine which aspect of the working memory system—short-term storage or cognitive control—drives the relationship with fluid intelligence. A sample of 119 children was followed from kindergarten to second grade and completed multiple assessments of working memory, short-term memory, and fluid intelligence. The data showed that working memory, short-term memory, and fluid intelligence were highly related but separate constructs in young children. The results further showed that when the common variance between working memory and short-term memory was controlled, the residual working memory factor manifested significant links with fluid intelligence whereas the residual short-term memory factor did not. These findings suggest that in young children cognitive control mechanisms rather than the storage component of working memory span tasks are the source of their link with fluid intelligence.     

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.     

Superior fluid intelligence in children with Asperger's disorder

Asperger's disorder is one of autistic spectrum disorders; sharing clinical features with autism, but without developmental delay in language acquisition. There have been some studies of intellectual functioning in autism so far, but very few in Asperger's disorder. In the present study, we investigated abstract reasoning ability, whose form of intelligence has been labeled fluid intelligence in the theory of Cattell [Cattell, R. B. (1963). Theory of fluid and crystallized intelligence: A critical experiment. Journal of Educational Psychology, 54, 1-22.], in children with Asperger's disorder. A test of fluid intelligence, the Raven's Standard Progressive Matrices Test, was administered to 17 children with Asperger's disorder and 17 age-, gender-, and FIQ-matched normal children. The results showed that children with Asperger's disorder outperformed on the test of fluid reasoning than typically developing children. We suggest that individuals with Asperger's disorder have higher fluid reasoning ability than normal individuals, highlighting superior fluid intelligence.     

Relation of Creativity to Fluid and Crystallized Intelligence

The threshold hypothesis regarding creativity and intelligence suggests that these two constructs are positively correlated except at the higher end of the IQ distribution, where they are unrelated. Much of the support for this hypothesis comes from comparisons of correlations within average and high‐IQ groups. However, a common methodological flaw in these comparisons is that the high IQ group is smaller in variance than the average IQ group. In the present study we equated variances for a better test of the threshold hypothesis. College students in two IQ groups completed tests of creativity and intelligence. IQ and creativity correlated at least as strongly in the high IQ group as in the average IQ group, generally failing to support the threshold hypothesis. However, breakdown of composite IQ into fluid and crystallized IQ indicated minimal support for the threshold hypothesis with crystallized IQ, but support for an inverse threshold effect with fluid IQ. Fluid IQ correlated significantly with creativity in the high IQ group but not in the average IQ group, and this pattern was corroborated by regression analyses. Possible explanations for the pattern of results are offered.     

Intellectual growth in children as a function of domain specific and domain general working memory subgroups

This study examined whether children's growth on measures of fluid (Raven Colored Progressive Matrices) and crystallized (reading and math achievement) intelligence was attributable to domain-specific or domain-general functions of working memory (WM). A sample of 290 elementary school children was tested on measures of intelligence across three testing waves. Two methods, a hierarchical factor model predicting latent growth and a double dissociation design comparing children divided into high and low performers, tested whether general and/or specific components accounted for performance on intelligence measures. A general domain model for the total sample provided the best fit for latent growth on all measures. Further, the lack of a significant WM subgroup × domain interaction suggested that a general WM system underlies the individual differences on measures of fluid and crystallized intelligence. Overall, the findings support a domain-general view of WM capacity on intelligence measures in children, but also suggest that domain specific storage systems may come into play on isolated measures.     

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.     

Fluid intelligence is independently associated with all-cause mortality over 17 years in an elderly community sample: An investigation of potential mechanisms

The long-term relationship between lower intelligence and mortality risk in later life is well established, even when controlling for a range of health and sociodemographic measures. However, there is some evidence for differential effects in various domains of cognitive performance. Specifically, tests of fluid intelligence may have a stronger association with mortality than do tests of crystallized intelligence. The present study examines the relationship between intelligence and mortality in a sample of 896 Australian community-dwelling males and females, aged 70–97 at recruitment and followed for up to 17 years. There were 687 deaths during the follow-up period. Cox proportional hazard regression models examined whether the relationship between intelligence and mortality might be mediated by socioeconomic status, by health behaviors, by health status, or a combination of these. Higher fluid intelligence — as measured by the Symbol–Letter Modalities Test — was strongly associated with lower mortality rates (Hazard ratio = 0.80; 95% confidence interval = 0.72–0.88), even after accounting for any combination of potential mediators and confounders. A significant association between crystallized intelligence, as measured by the National Adult Reading Test, and mortality (HR = 0.89; 95% CI = 0.80–0.99) was attenuated by the inclusion of socioeconomic, health status measures, and health behavior measures and when deaths from the first four years of the study were excluded. The findings show little support for the hypothesized mechanisms of the intelligence–mortality relationship.     

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).     

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.     

The validity of the Comprehensive Test of Nonverbal Intelligence as a measure of fluid intelligence

The current investigation examined the validity of the Comprehensive Test of Nonverbal Intelligence (CTONI), an intelligence test that is purported to measure fluid intelligence. The CTONI was evaluated in comparison with the Kaufman Adolescent and Adult Intelligence Test (KAIT), an established measure of fluid and crystallized intelligence. Ninety-seven adults were administered these instruments in counterbalanced order. Results indicated that the sample's mean CTONI Nonverbal IQ (NIQ) deviated significantly from the mean KAIT Crystallized, Fluid, and Composite IQs. The CTONI mean NIQ underestimated KAIT Fluid and Composite IQs when individual participants were subdivided into existing KAIT ability categories and mean score comparisons were made. Results also indicated that the CTONI NIQ correlated strongly and positively with the KAIT Composite and Fluid IQs. Furthermore, the CTONI Geometric NIQ scale clearly demonstrated discriminant and convergent validity, whereas, the CTONI Pictorial NIQ (PNIQ) did not.     

The influence of inhibitory processes on affective theory of mind in young and old adults

The primary aim of this study was to examine the impact of an inhibition manipulation on the effect of age on theory of mind (ToM) in an ecologically valid, affective ToM task. Participants were 30 young and 30 old adults. The Cambridge Mindreading Face-Voice Battery was used to measure ToM; in addition, measures of fluid and crystallized intelligence were taken. Participants were subjected to three levels of inhibitory demand during ToM reasoning: emotional inhibition, non-emotional inhibition, and no inhibition. Old adults performed worse than young adults. The emotional and non-emotional inhibition conditions resulted in worse ToM performance compared to the no inhibition condition. There were no differences in the impact of the inhibition conditions on old and young adults. Regression analyses suggested that old adults’ crystallized intelligence was a significant predictor of ToM performance, whereas it did not predict young adults’ ToM performance. Results are discussed in terms of verbal ability as a possible compensatory mechanism in coping with verbal inhibitory load in ToM reasoning.     

On the interpretation of the CHC factor Gc

On the one hand, the factors Gf and Gc in the Cattell-Horn-Carroll (CHC) model of intelligence are hypothesized to represent individual differences in unique psychological or biological capacities. On the other hand, they are interpreted as representing the theoretical variables fluid and crystallized intelligence in investment theory. With respect to Gc, this leads to a theoretical conflict because in investment theory crystallized intelligence is not a capacity but purely a statistical entity. We contend that if CHC factor Gc represents a capacity, it cannot represent crystallized intelligence, and if Gc represents crystallized intelligence, it does not represent a capacity. In addition, from our discussion of Gc, we conclude that in investment theory the factors Gf and g represent one and the same capacity. In support of our theoretical conclusions, we implemented the CHC model in a confirmatory factor analysis of a HCA (Human Cognitive Abilities project) data set. As expected, Gf and g were statistically indistinguishable. Gc was effectively absent, because it was statistically equivalent to verbal comprehension. Factors Gc and g could be removed from the model without any reduction in model fit. We argue that in the CHC taxonomy the factors Gc and g are redundant as explanatory variables.     

Environment and high IQ—A consideration of fluid and crystallized intelligence

Attention is drawn to some causes of distancing between fluid and crystallized intelligence through detailed testing, environmental observations and responses of 210 children, their families and teachers. High Gc children (with IQ scores of 141+) were associated with educationally-superior home backgrounds, but not with abnormal emotional or personality features. High Gf children (99th% Raven's scorers) were found to reflect specifically the Cultural Milieu and Achievement-Related Facilities of their homes in their high IQ scores, but where Gf was insufficiently provided with opportunity, Gc appeared to suffer.Calculated proportions of fluid and crystallized intelligence in high IQ were varied, the scores becoming more heavily loaded with environmental influences towards the top of the scale, being 26% for children of exceptionally-high Gf and 13% for those of average to high Gf. It is suggested that where an IQ test is used, a cut-off point of IQ 130 be taken for the identification of intellectually-gifted children, along with verbal and other specific-ability tests.     

Factor structure of the Peabody Individual Achievement Test at five grade levels between grades one and 12

The Peabody Individual Achievement Test was factor analyzed at five grade levels. The two-factor solution was retained at each grade. Subtests composing each factor changed from the lower to upper grade levels, but the abilities measured by each factor appear constant. A close similarity between the two factors and Cattell's concept of fluid and crystallized intelligence was noted. Subtests' specificities were computed at each grade level investigated and implications for use and interpretation of the PIAT discussed.