A genetic two-factor model of the covariation among a subset of Multidimensional Aptitude Battery and Wechsler Adult Intelligence Scale—Revised subtests

The phenotypic and genetic factor structure of performance on five Multidimensional Aptitude Battery (MAB) subtests and one Wechsler Adult Intelligence Scale—Revised (WAIS-R) subtest was explored in 390 adolescent twin pairs (184 monozygotic [MZ]; 206 dizygotic (DZ)). The temporal stability of these measures was derived from a subsample of 49 twin pairs, with test–retest correlations ranging from .67 to .85. A phenotypic factor model, in which performance and verbal factors were correlated, provided a good fit to the data. Genetic modeling was based on the phenotypic factor structure, but also took into account the additive genetic (A), common environmental (C), and unique environmental (E) parameters derived from a fully saturated ACE model. The best fitting model was characterized by a genetic correlated two-factor structure with specific effects, a general common environmental factor, and overlapping unique environmental effects. Results are compared to multivariate genetic models reported in children and adults, with the most notable difference being the growing importance of common genes influencing diverse abilities in adolescence.     

Structure of the Wechsler Adult Intelligence Scale – Revised in the Italian Normal Standardisation Sample

Six multifactor correlated traits models and a single-factor model of the WAIS-R's factor pattern were examined by confirmatory maximum likelihood factor analyses of a data matrix from the WAIS-R's Italian normative sample raw scores (N=2284). The main aim was to identify what model(s) best fit(s) the data for the different age groups considered. Analyses were designed to determine which of seven hypothesised factor solutions best explained the intellectual ability of four age bands (16 to 74 years of age) and of all samples. Results showed the same three-correlated-factors model (Verbal, Performance, and Freedom From Distractibility) for the younger (16 to 24 years of age) and for more aged (65 to 74 years of age), and two different three-factor models for the adult (band from 25 to 64 years of age) that had in common the presence of Digit Symbol loading on Freedom From Distractibility, that in the younger and aged band loaded on Perceptual Organisation. The individuals may use different strategies when performing a given task on the WAIS-R. Such differences in latent variability may represent real differences in neuropsychological functioning, and as such can account for some of the variability in results noted in the literature. Differences in latent variability across distinct demographic and clinical groups could provide important insight into brain–behaviour relationships.     

The Meta-Contrast Technique: relationships with personality traits and cognitive abilities in healthy women

The relationship between test results from the Meta-Contrast Technique (MCT) and self-reports from Karolinska Scales of Personality (KSP), or the State Trait Anxiety Inventory (STAI-T), was investigated in 100 healthy women. Additionally, it was investigated whether age and cognitive abilities influenced the reports of picture recognition thresholds in the MCT. The results showed no agreement between the different ways to assess anxiety and defensiveness. However, age consistently predicted later reports of the perceptual recognition thresholds A1 (the car), A2 (the face) and C-phase. The WAIS-R Digit Symbol Score predicted earlier reporting of the recognition thresholds A1 and A2, but did not predict the final criteria for correct recognition (C-phase). The KSP aggression factor only predicted an earlier report of recognition threshold A2. The absence of a simple relationship between the different ways to assess anxiety and defensiveness, and the observed relationships regarding perceptual threshold levels, corroborates previous findings.