Funciones ejecutivas y alta capacidad intelectual / Executive functions and high intellectual capacity

Introducción. La alta capacidad intelectual es un proceso en desarrollo en el que las funciones ejecutivas (inhibición, memoria de trabajo y flexibilidad) desempeñan un papel en la manifestación óptima de su potencial. Objetivo. Explorar la eficacia del funcionamiento ejecutivo entre los perfiles de alta capacidad de superdotación y talento (convergente o divergente). Sujetos y métodos. Se estudiaron 78 niños con alta capacidad intelectual de 8-15 años con perfiles de superdotación (n = 21), talento convergente (n = 39) o talento divergente (n = 18). Se administró la batería de aptitudes diferenciales y generales o el Differential Aptitude Test (según la edad) y el test de pensamiento creativo de Torrance, además del test de clasificación de tarjetas de Wisconsin, el test de Corsi y el test go-no go mediante la plataforma Psychology Experiment Building Language. Se realizó un análisis multivariado de la varianza para conocer la relación entre función ejecutiva y perfi l intelectual. Resultados. Se obtienen diferencias significativas entre los perfiles estudiados y las funciones ejecutivas de fl exibilidad e inhibición, pero no en la memoria de trabajo. Conclusión. La memoria de trabajo es similar entre los perfiles estudiados, pero el perfil complejo de superdotación muestra mejor funcionamiento ejecutivo, con mayor flexibilidad e inhibición que el talento, especialmente el convergente (AU)

Introduction. High intellectual capacity is a process in development in which the executive functions (inhibition, working memory and fl exibility) play a role in the optimal manifestation of their potential. Aim. To explore the eff ectiveness of executive functioning among the profi les of high capacity giftedness and (convergent or divergent) talent. Subjects and methods. The study examines 78 children with high intellectual capacity aged 8-15 years with profi les of giftedness (n = 21), convergent talent (n = 39) or divergent talent (n = 18). A series of tests were administered including the Battery of Diff erential and General Aptitudes or the Diff erential Aptitude Test (depending on the age) and the Torrance Test of Creative Thinking, as well as the Wisconsin Card Sorting Test, the Corsi Test and the Go-No Go Test by means of the Psychology Experiment Building Language platform. A multivariate analysis of variance was performed to determine the relationship between executive function and intellectual profi le. Results. Signifi cant diff erences are obtained between the profi les studied and the executive functions of fl exibility and inhibition, but not in working memory. Conclusion. Working memory is similar across the profi les studied, but the complex profi le of giftedness displays better executive functioning, with greater fl exibility and inhibition than talent, especially of the convergent type (AU)

Mental rotation in intellectually gifted boys is affected by the androgen receptor CAG repeat polymorphism.

Testosterone was shown to organize brain and modulate cognitive functions. It is currently unknown whether mental rotation is also associated with prenatal testosterone exposure and testosterone-related genetic polymorphisms. The aim of our study was to analyze associations between mental rotation performance, the actual testosterone levels, the prenatal testosterone level (expressed as 2D:4D ratio) and the androgen receptor CAG repeat polymorphism in intellectually gifted boys. One hundred forty-seven boys aged 10-18 years with IQ>130 were enrolled. Saliva samples were collected and used for ELISA of actual levels of salivary testosterone. The 2D:4D finger length ratio as an indicator of prenatal testosterone was measured on both hands and averaged. Amthauer mental rotation test was used for the assessment of this spatial ability. The CAG repeat polymorphism in the androgen receptor gene was analyzed using PCR and capillary electrophoresis. Linear regression revealed that 2D:4D finger length ratio and the number of CAG repeats in the androgen receptor gene were associated with mental rotation. Actual levels of testosterone did not correlate significantly with mental rotation. Multivariate analysis of covariance revealed that after adjustment of age as a confounding variable, only the effect of the genetic polymorphism was significant. The results are in line with our previous genetic analysis of intellectually gifted boys showing the importance of CAG repeat polymorphism in the androgen receptor gene. Details of the interactions between androgen signaling, testosterone levels and its metabolism especially during the prenatal development of brain function remain to be elucidated.

Genetic covariation between theAuthor Recognition Test and reading and verbal abilities: what can we learn from the analysis of high performance?

The Author Recognition Test (ART) measures print exposure and is a unique predictor of phonological and orthographic processes in reading. In a sample of adolescent and young adult twins and siblings (216 MZ/430 DZ pairs, 307 singletons; aged 11-29 years) ART scores were moderately heritable (67%) and correlated with reading and verbal abilities, with genes largely accounting for the covariance. We also examine whether high (and low) (i.e. 1SD above the mean) represents a quantitative extreme of the normal distribution. Heritability for high ART was of similar magnitude to the full sample, but, a specific genetic factor, independent from both low ART performance and high reading ability, accounted for 53-58% of the variance. This suggests a distinct genetic etiology for high ART ability and we speculate that the specific genetic influence is on orthographical processing, a critical factor in developing word recognition skills.

Exceptional cognitive ability: the phenotype.

Characterizing the outcomes related to the phenotype of exceptional cognitive abilities has been feasible in recent years due to the availability of large samples of intellectually precocious adolescents identified by modern talent searches that have been followed-up longitudinally over multiple decades. The level and pattern of cognitive abilities, even among participants within the top 1% of general intellectual ability, are related to differential developmental trajectories and important life accomplishments: The likelihood of earning a doctorate, earning exceptional compensation, publishing novels, securing patents, and earning tenure at a top university (and the academic disciplines within which tenure is most likely to occur) all vary as a function of individual differences in cognitive abilities assessed decades earlier. Individual differences that distinguish the able (top 1 in 100) from the exceptionally able (top 1 in 10,000) during early adolescence matter in life, and, given the heritability of general intelligence, they suggest that understanding the genetic and environmental origins of exceptional abilities should be a high priority for behavior genetic research, especially because the results for extreme groups could differ from the rest of the population. In addition to enhancing our understanding of the etiology of general intelligence at the extreme, such inquiry may also reveal fundamental determinants of specific abilities, like mathematical versus verbal reasoning, and the distinctive phenotypes that contrasting ability patterns are most likely to eventuate in at extraordinary levels.

Generalist genes and high cognitive abilities.

The concept of generalist genes operating across diverse domains of cognitive abilities is now widely accepted. Much less is known about the etiology of the high extreme of performance. Is there more specialization at the high extreme? Using a representative sample of 4,000 12-year-old twin pairs from the UK Twins Early Development Study, we investigated the genetic and environmental overlap between web-based tests of general cognitive ability, reading, mathematics and language performance for the top 15% of the distribution using DF extremes analysis. Generalist genes are just as evident at the high extremes of performance as they are for the entire distribution of abilities and for cognitive disabilities. However, a smaller proportion of the phenotypic intercorrelations appears to be explained by genetic influences for high abilities.

The developmental etiology of high IQ.

The genetic and environmental trends in IQ development were assessed in 483 same-sex twin pairs in the Colorado longitudinal twin study using maximum-likelihood model-fitting analysis. The twins were assessed periodically from ages 1 to 16. Results show a decreasing influence of shared environment and an increasing influence of heritability across development, with large and increasing age to age stability of genetic influences. Non-shared environment contributes almost exclusively to age to age change. Similar analyses were conducted designating the top 15% of the sample as having high IQ at each age. The developmental etiology of high IQ did not significantly differ from that found for the continuous measure in this relatively novel analysis. These results demonstrate early stability in etiological influences on IQ and have potential implications for gene-finding efforts, suggesting that samples selected for high IQ can be used to find genetic variation that will be applicable to the full range of the IQ distribution, although conclusive demonstration that the same genes are indeed involved was beyond the scope of this study.

Shared-environmental contributions to high cognitive ability.

Using a combined sample of adolescent twins, biological siblings, and adoptive siblings, we estimated and compared the differential shared-environmentality for high cognitive ability and the shared-environmental variance for the full range of ability during adolescence. Estimates obtained via multiple methods were in the neighborhood of 0.20, and suggest a modest effect of the shared environment on both high and full-range ability. We then examined the association of ability with three measures of the family environment in a subsample of adoptive siblings: parental occupational status, parental education, and disruptive life events. Only parental education showed significant (albeit modest) association with ability in both the biological and adoptive samples. We discuss these results in terms of the need for cognitive-development research to combine genetically sensitive designs and modern statistical methods with broad, thorough environmental measurement.

A twin study of the genetics of high cognitive ability selected from 11,000 twin pairs in six studies from four countries.

Although much genetic research has addressed normal variation in intelligence, little is known about the etiology of high cognitive abilities. Using data from 11,000 twin pairs (age range = 6-71 years) from the genetics of high cognitive abilities consortium, we investigated the genetic and environmental etiologies of high general cognitive ability (g). Age-appropriate psychometric cognitive tests were administered to the twins and used to create g scores standardized within each study. Liability-threshold model fitting was used to estimate genetic and environmental parameters for the top 15% of the distribution of g. Genetic influence for high g was substantial (0.50, with a 95% confidence interval of 0.41-0.60). Shared environmental influences were moderate (0.28, 0.19-0.37). We conclude that genetic variation contributes substantially to high g in Australia, the Netherlands, the United Kingdom and the United States.

The heritability of aptitude and exceptional talent across different domains in adolescents and young adults.

The origin of individual differences in aptitude, defined as a domain-specific skill within the normal ability range, and talent, defined as a domain specific skill of exceptional quality, is under debate. The nature of the variation in aptitudes and exceptional talents across different domains was investigated in a population based twin sample. Self-report data from 1,685 twin pairs (12-24 years) were analyzed for Music, Arts, Writing, Language, Chess, Mathematics, Sports, Memory, and Knowledge. The influence of shared environment was small for both aptitude and talent. Additive and non-additive genetic effects explained the major part of the substantial familial clustering in the aptitude measures with heritability estimates ranging between .32 and .71. Heritability estimates for talents were higher and ranged between .50 and .92. In general, the genetic architecture for aptitude and talent was similar in men and women. Genetic factors contribute to a large extent to variation in aptitude and talent across different domains of intellectual, creative, and sports abilities.

Heritability of high reading ability and its interaction with parental education.

Moderation of the level of genetic influence on children's high reading ability by environmental influences associated with parental education was explored in two independent samples of identical and fraternal twins from the United States and Great Britain. For both samples, the heritability of high reading performance increased significantly with lower levels of parental education. Thus, resilience (high reading ability despite lower environmental support) is more strongly influenced by genotype than is high reading ability with higher environmental support. This result provides a coherent account when considered alongside results of previous research showing that heritability for low reading ability decreased with lower levels of parental education.

Family background and genius.

OBJECTIVE: It is widely believed among professionals and laity that genius is born and not made. However, the early and still-influential statistical studies of Frances Galton on the inheritance of genius have neither been supported nor definitively refuted. This study empirically assesses the hereditary transmission hypothesis. METHODS: We collected family background data on 50 Nobel Prize laureates in literature, 31 Booker Prize awardees, 135 Pulitzer Prize winners, and 20 National Book and National Book Critics Circle awardees. We compared these for incidence of occupational inheritance (that is, same parent-child occupations) with a matching group of 392 eminent persons in noncreative occupations; for predominant occupation type, we also compared subject data with data for 560 high-IQ nonprizewinners, as well as with general population occupational data. RESULTS: Incidence of one or both parents in the same occupation was only 1% for literary prizewinners but 16% for eminent noncreative persons (P < 0.0001). The predominant (76%) family background constellation for prizewinners consisted of parent-child sex congruency either in applied-equivalent occupations requiring language, persuasion, or artisan skills (P < 0.0001, compared with control subjects) or in unrelated occupations with unfulfilled wishes for creative expression. CONCLUSIONS: Outstanding literary prizewinners do not manifest direct inheritance of creativity from their parents; instead, parents and children of the same sex are predominantly in applied-equivalent or performance occupations and have unfulfilled creative wishes. We suggest that early developmental influences on child motivation involve identification and competition with the parent of the same sex.

Psychological profiles of the mathematically talented: some sex differences and evidence supporting their biological basis.

For over 20 years, above-level testing with the College Board Scholastic Aptitude Test (SAT) has been used to assess the abilities of well over 1,000,000 highly able 12-13-year-olds (students in the top 3% in intellectual ability). In this population, the predictive validity of the mathematical part of the SAT, SAT-M, for academic and vocational criteria has been demonstrated over 10-year gaps. Here, we document aspects of the psychological and achievement profiles of these highly able students, paying particular attention to sex differences. Males score higher on SAT-M (i.e., mathematical reasoning ability) than females; this difference is accompanied by differences between the sexes in spatial-mechanical reasoning abilities and in a number of lifestyle and vocational preferences. Collectively, these attributes appear to play a key role in structuring male-female disparities in pursuing advanced educational credentials and careers in the physical sciences. After profiling a number of the behavioural characteristics of the highly able, we examine some underlying biological correlates of these phenotypic manifestations. These include hormonal influences, medical and bodily conditions and enhanced right hemispheric activation.

Genetics and high cognitive ability.

More is known about the genetics of general cognitive ability (g) than any other trait in psychology. Recent findings on the genetics of g include the following three examples: (1) heritability increases throughout the lifespan; (2) heritabilities of performance in cognitive tests are strongly correlated with the tests' loadings on a g factor; and (3) genetic effects on scholastic achievement largely overlap with genetic effects on cognitive ability. This body of genetic research addresses the aetiology of individual differences in the normal range. Much less is known about the genetics of the high end of the distribution. Finding heritability in the normal range of cognitive ability does not imply that high ability is also genetic in origin. However, the first twin study of high IQ children, which uses a new technique that analyses the average difference between extreme groups and the rest of the population, suggests that high IQ is as heritable as individual differences in the normal range. We are currently engaged in a molecular genetic study that attempts to identify specific genes that contribute to high ability.