Sergio Escorial

Age dedifferentiation hypothesis: Evidence from the WAIS III

There is a renewed interest in the so-called age differentiation hypothesis—and the related age dedifferentiation hypothesis. The former states a reduction in the size of g at the first stage of life until early maturity. The latter hypothesized an increase in the importance of g at late adulthood and a decrease in the number of factors. The Spanish standardization of the WAIS-III (N=1369) was used in the present study to test the age dedifferentiation hypothesis. The results show no changes in the percentage of variance accounted for by g and four group factors (Verbal, Perceptual Organization, Working Memory, and Processing Speed) when the restriction of range is controlled. The ageindifferentiation hypothesis, as well as the anatomical metaphor, is proposed as a more fine-grained perspective to look at the development of the structure of cognitive abilities along the life span. D 2002 Elsevier Science Inc. All rights reserved.

Sex differential item functioning in the Raven's Advanced Progressive Matrices: evidence for bias

There are no sex differences in general intelligence or g. The Progressive Matrices (PM) Test is one of the best estimates of g. Males outperform females in the PM Test. Colom and Garcia-Lopez (2002) demonstrated that the information content has a role in the estimates of sex differences in general intelligence. The PM test is based on abstract figures and males outperform females in spatial tests. The present study administered the Advanced Progressive Matrices Test (APM) to a sample of 1970 applicants to a private University (1069 males and 901 females). It is predicted that there are several items biased against female performance, by virtue of their visuo-spatial nature. A double methodology is used. First, confirmatory factor analysis techniques are used to contrast one and two factor solutions. Second, Differential Item Functioning (DIF) methods are used to investigate sex DIF in the APM. The results show that although there are several biased items, the male advantage still remains. However, the assumptions of the DIF analysis could help to explain the observed results.

Changes in resting-state functionally connected parietofrontal networks after videogame practice

Neuroimaging studies provide evidence for organized intrinsic activity under task‐free conditions. This activity serves functionally relevant brain systems supporting cognition. Here, we analyze changes in resting‐state functional connectivity after videogame practice applying a test–retest design. Twenty young females were selected from a group of 100 participants tested on four standardized cognitive ability tests. The practice and control groups were carefully matched on their ability scores. The practice group played during two sessions per week across 4 weeks (16 h total) under strict supervision in the laboratory, showing systematic performance improvements in the game. A group independent component analysis (GICA) applying multisession temporal concatenation on test–retest resting‐state fMRI, jointly with a dual‐regression approach, was computed. Supporting the main hypothesis, the key finding reveals an increased correlated activity during rest in certain predefined resting state networks (albeit using uncorrected statistics) attributable to practice with the cognitively demanding tasks of the videogame. Observed changes were mainly concentrated on parietofrontal networks involved in heterogeneous cognitive functions. Hum Brain Mapp 34:3143–3157, 2013.

Does g variance change in adulthood? Testing the age de-differentiation hypothesis across sex

In the last decade, changes in the structure of intelligence across the life-span has become a central topic in the research on human intelligence. One of the main hypotheses that has arisen to account for such changes has been the age de-differentiation hypothesis [Balinsky, Genetic Psychology Monographs 23 1941, 191]. It predicts an increase in the importance of g, and a decrease in the number and importance of the lower-order abilities from early maturity to senescence. Despite of the research effort to test this hypothesis, no study has ever been conducted controlling by sex. For that purpose, males and females of the Spanish standardisation sample of the WAIS-III were analysed separately. Results show that the importance of g does not change with age irrespective of sex. Thus, the age de-differentiation hypothesis is rejected for both males and females. The indifferentiation hypothesis is supported as a more appropriate view of the changes in the structure of intelligence across adulthood.

Reversed hierarchy in the brain for general and specific cognitive abilities: A morphometric analysis

Intelligence is composed of a set of cognitive abilities hierarchically organized. General and specific abilities capture distinguishable, but related, facets of the intelligence construct. Here, we analyze gray matter with three morphometric indices (volume, cortical surface area, and cortical thickness) at three levels of the intelligence hierarchy (tests, first‐order factors, and a higher‐order general factor, g). A group of one hundred and four healthy young adults completed a cognitive battery and underwent high‐resolution structural MRI. Latent scores were computed for the intelligence factors and tests were also analyzed. The key finding reveals substantial variability in gray matter correlates at the test level, which is substantially reduced for the first‐order and the higher‐order factors. This supports a reversed hierarchy in the brain with respect to cognitive abilities at different psychometric levels: the greater the generality, the smaller the number of relevant gray matter clusters accounting for individual differences in intelligent performance. Hum Brain Mapp 35:3805–3818, 2014.

Structural Analysis of the Facets and Domains of the Zuckerman–Kuhlman–Aluja Personality Questionnaire (ZKA–PQ) and the NEO PI–R

Aluja, Kuhlman, and Zuckerman (2010) developed an instrument for American and Spanish populations (Zuckerman–Kuhlman–Aluja Personality Questionnaire [ZKA–PQ]) that includes 4 facets for each 5 basic traits of Zuckermans psychobiological personality model. This new instrument is intended to improve the previous measure based on the same personality model, the Zuckerman–Kuhlman Personality Questionnaire (ZKPQ), by including the narrower traits (facets) defining the factors. This article explores the convergent and discriminant validity of the new instrument relative to the NEO PI–R in a sample from the Spanish general population. A series of exploratory factor analyses comparing both instruments was conducted. Results showed good convergent and discriminant validity between both instruments, although the ZKA–PQ had a slightly better structure than the NEO PI–R. The results support the validity of the ZKA–PQ factor domains and the facets composing them. The new instrument might be useful in both applied and research settings.

Sex differences in neocortical structure and cognitive performance: A surface-based morphometry study.

On average, men show larger brain volumes than women. Regional differences have been also observed, although most of the available studies apply voxel-based morphometry (VBM). Reports applying surface-based morphometry (SBM) have been focused mainly on cortical thickness (CT). Here we apply SBM for obtaining global and regional indices of CT, cortical surface area (CSA), and cortical gray matter volume (CGMV) from samples of men (N=40) and women (N=40) matched for their performance on four cognitive factors varying in their complexity: processing speed, attention control, working memory capacity, and fluid intelligence. These were the main findings: 1) CT and CSA produced very weak correlations in both sexes, 2) men showed larger values in CT, CSA, and CGMV, and 3) cognitive performance was unrelated to brain structural variation within sexes. Therefore, we found substantial group differences in brain structure, but there was no relationship with cognitive performance both between and within-sexes.

Analysis of the Gender Variable in the Eysenck Personality Questionnaire–Revised Scales Using Differential Item Functioning Techniques

Studies in the field of personality have systematically found gender differences in two of the three dimensions of the Eysenck model: neuroticism and psychoticism. This study aims to analyze these differences in the Eysenck Personality Questionnaire—Revised (EPQ-R) scales using differential item functioning (DIF) techniques to determine whether these differences are the result of a differential functioning of the items between males and females or if, on the contrary, they may be reflecting true differences in the assessed dimensions. To this end, 794 participants within a wide age range were evaluated using the EPQ-R test. The following detection methods were used in order to examine DIF: standardization, the simultaneous item bias test, logistic regression, Lords χ2 test, and the differential functioning of items and tests framework. According to the results, the gender differences observed do not seem to be the result of any flaw of the measuring instrument used.

Testing the Indifferentiation Hypothesis during Childhood, Adolescence, and Adulthood.

The general (g) factor is the most general and relevant cognitive ability. This factor is considered to be one of the most important predictors of academic achievement and of many other socially relevant behavioral outcomes. In the last decades, many researchers have investigated the possible changes in the relevance of the g factor from childhood to adulthood. The indifferentiation hypothesis states that the variance attributed to the g factor and the main cognitive abilities will not change over the life span. In the present study, the authors tested that hypothesis in childhood, adolescence, and adulthood by using 2 different cognitive batteries (Test of Educational Ability [TEA; S. A. TEA, 1999], Wechsler Adult Intelligence Scales [WAIS; D. Wechsler, 1955]), which they administered in 2 different countries-Spain (TEA) and the United States (WAIS). The ages of the participants (N = 2,384) ranged from 8 to 54 years. Results showed that the number of factors extracted and the relevance were the same for every age group in both batteries, as predicted by the indifferentiation hypothesis. The authors discuss implications of intelligence assessment.

Zuckerman-Kuhlman-Aluja Personality Questionnaire (ZKA-PQ) and Cloninger's Temperament and Character Inventory Revised (TCI-R): A comparative study

The aim of this study was to compare the psychometric properties (normal distribution values, reliabilities and factor structure) of the Zuckerman-Kuhlman-Aluja Personality Questionnaire (ZKA-PQ) and the Temperament and Character Inventory revised (TCI-R). The total sample consisted of 482 subjects (53.1% men and 46.9% women) from diverse age. Results showed somewhat better psychometric properties, like reliability and facet-factor structure, for the ZKA-PQ than the TCI-R. The expected five-factor facet structure of the ZKA-PQ was clear found. However, the seven-factor structure of TCI-R was not clear and it did not show a clear distinction between Temperament and Character factors. When ZKA-PQ and TCI-R variables are analyzed together, the ZKA-PQ factors are related to the Character as well as the Temperament factors. In some cases they represent the opposite poles of ZKA-PQ factors; for example, Neuroticism versus Self-Directiveness and Aggression versus Cooperativeness. Some are directly and highly related to ZKA-PQ factors; for example, Sensation Seeking and Novelty Seeking, Extraversion and Reward Dependence, Neuroticism and Harm Avoidance, and Activity and Persistence.