Intelligence and semen quality are positively correlated

Human cognitive abilities inter-correlate to form a positive matrix, from which a large first factor, called ‘Spearman's g’ or general intelligence, can be extracted. General intelligence itself is correlated with many important health outcomes including cardio-vascular function and longevity. However, the important evolutionary question of whether intelligence is a fitness-related trait has not been tested directly, let alone answered. If the correlations among cognitive abilities are part of a larger matrix of positive associations among fitness-related traits, then intelligence ought to correlate with seemingly unrelated traits that affect fitness—such as semen quality. We found significant positive correlations between intelligence and 3 key indices of semen quality: log sperm concentration (r = .15, p = .002), log sperm count (r = .19, p < .001), and sperm motility (r = .14, p = .002) in a large sample of US Army Veterans. None was mediated by age, body mass index, days of sexual abstinence, service in Vietnam, or use of alcohol, tobacco, marijuana, or hard drugs. These results suggest that a phenotype-wide fitness factor may contribute to the association between intelligence and health. Clarifying whether a fitness factor exists is important theoretically for understanding the genomic architecture of fitness-related traits, and practically for understanding patterns of human physical and psychological health.     

Do sex differences in a faceted model of fluid and crystallized intelligence depend on the method applied?

Recently, different methodological approaches have been discussed as an explanation for inconsistencies in studies investigating sex differences in different intelligences. The present study investigates sex differences in manifest sum scores, factor score estimates, and latent verbal, numerical, figural intelligence, as well as fluid and crystallized intelligence as measured by the German Intelligence-Structure-Test 2000-R (IST 2000-R; Liepmann, Beauducel, Brocke, & Amthauer, 2007). The not population-representative sample consisted of 977 German 11th and 12th graders enrolled in a “Gymnasium” (551 female; mean age: M = 16.70; SD = 0.65) who completed the IST 2000-R. Sex differences in fluid and crystallized intelligence were not influenced by the method applied with men performing better than women. However, extent and direction of sex differences in verbal, numerical, and figural intelligence differed by the method applied. Whereas there was a male advantage in all three factors measured as manifest sum scores, women performed better in verbal intelligence as measured by factor scores or as latent variables. Effect sizes of sex differences in numerical and figural intelligence were also greatly reduced when applying the latter two methods. Results are discussed with regard to their theoretical and practical implications.     

Personality,intelligence and proof-reading

Two studies sought to determine personality and cognitive ability correlates of proof-reading. In both studies candidates were given 5 min to identify up to 55 errors in a 920 word, two page document. In Study 1, which tested 240 school children, fluid intelligence (as measured by the Baddeley Reasoning Test) was the highest correlate of proof-reading (r = .30). Eleven percent of the variance in total attempted scores was accounted for by intelligence, Introversion and low Conscientiousness. In the second study 70 undergraduates completed the same proof-reading test along with two intelligence tests (Baddeley Reasoning Test; Wonderlic Personnel Test) and a more robust personality measure (NEO-FFI). Proof-reading was correlated with both intelligence tests (Baddeley r = .45; Wonderlic r = .40). More of the variance was accounted for in the total attempted-score of errors than for a correct errors-detected score. When the two intelligence and five personality trait scores were regressed on to the proof-reading test score over a quarter of the variance (Adj R² = .28) was accounted for, but only the Baddeley test was a significant predictor (Beta = .39).     

Childhood IQ and in-service mortality in Scottish Army personnel during World War II

The Scottish Mental Survey of 1932 (SMS1932) provides a record of intelligence test scores for almost a complete year-of-birth group of children born in 1921. By linking UK Army personnel records, the Scottish National War Memorial data, and the SMS1932 dataset it was possible to examine the effect of childhood intelligence scores on wartime military service mortality in males. There were 491 matches between World War II (WWII) Scottish Army fatalities and the SMS1932 database; 470 (96%) had an age 11 mental ability score recorded. The mean (S.D.) age 11 IQ score of those who died on active service in WWII was 100.78 (15.56), compared with 97.42 (14.87) for male Army survivors (p < 0.0001; Cohen's d = 0.22). Men who took part in the SMS1932 and who were not found in the Army database had a higher mean score (100.45, S.D. =14.97) than those men who had been in the Army, regardless of whether they died or survived (mean IQ = 97.66, S.D. = 14.94; p < 0.0001; Cohen's d = 0.19). Male soldiers with a higher childhood IQ had a slightly increased risk of dying during active service in WWII. Men who did not join the Army had a higher IQ than men who did. Further research in this area should consider naval and air force personnel records in order to examine more fully the complex relationship between IQ and survival expectancy during active service in WWII.     

Advanced age brings a greater reliance on visual feedback to maintain balance during walking

We implemented a virtual reality system to quantify differences in the use of visual feedback to maintain balance during walking between healthy young (n = 12, mean age: 24 years) and healthy old (n = 11, 71 years) adults. Subjects walked on a treadmill while watching a speed-matched, virtual hallway with and without mediolateral visual perturbations. A motion capture system tracked center of mass (CoM) motion and foot kinematics. Spectral analysis, detrended fluctuation analysis, and local divergence exponents quantified old and young adults’ dynamic response to visual perturbations. Old and young adults walked normally with comparable CoM spectral characteristics, lateral step placement temporal persistence, and local divergence exponents. Perturbed visual flow induced significantly larger changes in mediolateral CoM motion in old vs. young adults. Moreover, visual perturbations disrupted the control of lateral step placement and compromised local dynamic stability more significantly in old than young adults. Advanced age induces a greater reliance on visual feedback to maintain balance during waking, an effect that may compensate for degradations in somatosensation. Our findings are relevant to the early diagnosis of sensory-induced balance impairments and also point to the potential use of virtual reality to evaluate sensory rehabilitation and balance training programs for old adults.     

Marital status and reproduction: Associations with childhood intelligence and adult social class in the Aberdeen children of the 1950s study

Childhood intelligence (age 11) and occupational social status at midlife (age 46 to 51) was associated with marital status and reproduction in a sample from the Aberdeen Children of the 1950s cohort study (N = 9614).Male and female divorcees had lower childhood intelligence test scores than their married counterparts, but no meaningful difference was found between ever- and never-married individuals. Lower occupational social status increased the odds of being never-married, divorced, separated or widowed compared to being married by 53% to 26% in men (N = 2716) but not in women (N = 2920). Higher intelligence scores were associated with being married rather than divorced at midlife with odds ratios (OR) of 0.86 (Confidence Interval of 95% of 0.76 to 0.99) in men, and 0.87 (0.77 to 0.98) in women.In men, lower intelligence predicted having offspring (0.69; 0.59 to 0.81), while in women, higher occupational status was associated with lower odds of having children (0.66; 0.55 to 0.76). An interaction term showed that high intelligence women remained childless in the top occupational classes but, in the lower social groups, mothers were more intelligent than their childless peers. Intelligence or occupational status were not associated with the number of offspring in both sexes.     

Social status,cognitive ability,and educational attainment as predictors of liberal social attitudes and political trust

We examined the prospective associations between family socio-economic background, childhood intelligence (g) at age 11, educational and occupational attainment, and social attitudes at age 33 in a large (N = 8804), representative sample of the British population born in 1958. Structural equation Modeling identified a latent trait of ‘liberal social attitudes’ underlying attitude factors that are antiracist, socially liberal, and in support of gender equality. Another attitude factor—‘political trust’—was relatively independent from the latent attitude trait and has somewhat different pathways in relation to the other variables included in the analysis. There was a direct association between higher g at age 11 and more liberal social attitudes and political trust at age 33. For both men and women the association between g and liberal social attitudes was partly mediated via educational qualifications, and to a much lesser extent via adult occupational attainment. For women the association between g and political trust was partly mediated through both educational qualification and occupational attainment, and for men it was mediated mainly via occupational attainment. Men and women who had higher educational qualifications and higher occupational status tend to be more socially liberal and more trusting of the democratic political system. In terms of socio-economic background, people from less privileged families showed less political trust, but did not differ much in liberal social attitudes from those born into relatively more privileged circumstances. This study shows that social background, cognitive ability, education, and own social status influence perceptions of society.     

The stability and change of malaise scores over 27 years: Findings from a nationally representative sample

This study investigates the stability and change of malaise scores over a period of 27 years taking account of socio-demographic variables, childhood intelligence and behavioural problems. 6822 cohort members had the complete data on Malaise measured at 23, 33, 42, and 50 years. T-tests showed that there were significant changes of malaise mean scores over the 27 years: malaise scores decreased significantly from 23 to 33 years, but increased significantly from 33 to 42 years, and there were no significant change between 42 and 50 years. The trend showed a similar pattern for men and women, though women scored significantly higher than men on the measure at every time point. Correlational analysis showed that over 27 years malaise scores ranged from r = .41 to r = .52, indicating the relative stability. Malaise was significantly and inversely associated with childhood intelligence and behavioural problems. It was also significantly associated with education in the expected direction. Regression analysis showed that previous malaise scores were significant predictors of the later ones, and the strength of the predictive power decreased over time. Limitations were considered.     

Sur la différenciation des aptitudes cognitives de l'enfant

Data from the standardization sample of a French intelligence scale for children aged from 4 to 9 years (Échelles Différentielles d'Efficiences Intellectuelles) were examined to verify the ability differentiation hypothesis. The whole sample (n = 574) was divided into three age groups (4–5, 6–7 and 8–9 years) and multisample confirmatory factor analyses were performed. Results showed that correlations between subtests, factor loadings, correlation between factors, and residual variance of subtests were similar across age groups. This finding doesn't seem to be the consequence of a sampling bias or a positive correlation between age and reliability or variability of subtest scores. Like results of other recent research on this question, it challenges the hypothesis of a differentiation of abilities during childhood, at least when studies are conducted with intellectual composite scales applied to unselected samples of participants.     

Effet de l’exposition culturelle sur l’ajustement culturel : rôle médiateur de l’intelligence culturelle

The purpose of the study consists in examining the effect of cultural exposure onto cultural adjustment mediated by cultural intelligence. In this perspective, we have consolidated the conception of cultural exposure as well as validated the measure of cultural exposure in French. The data (n = 106) have been collected via an electronic survey administered to immigrants and processed via Jamovi 2.3.3.0. Further to the structural equation modeling in latent variables we have validated the hypothesized mediation. Another result consisted in a validated measure of cultural exposure. The findings are discussed in terms of their contribution to the understanding of the antecedents of cultural intelligence and cultural adjustment. Several recommendations are formulated for the institutions in charge for the immigrants’ integration and training.     

Trajectories of self-evaluation bias in primary and secondary school: Parental antecedents and academic consequences

Using a longitudinal approach spanning nine years of children's formal education, this study investigated the developmental trajectories of self-evaluation bias of academic competence. The study also examined how parenting styles were associated with the trajectories of bias in mid-primary school, and how those trajectories predicted academic outcomes at the end of secondary school and the beginning of college. A total of 711 children in 4th and 5th grades (mean age = 10.71 years old; 358 girls) participated in this study. Using a latent class growth modeling framework, results indicated that children can be classified in three latent growth trajectories of self-evaluation bias: the optimistic, realistic and pessimistic trajectories. These trajectories differed in their initial status of bias and also in their development over time. Children's adherence to a specific trajectory was associated with parenting variables in childhood. Finally, the optimistic, realistic, or pessimistic trajectories distinctively predicted achievement and persistence.     

Sense of direction: General factor saturation and associations with the Big-Five traits

The ability to locate and orient ourselves with respect to environmental space is known as sense of direction (“SOD”). While there is considerable evidence for the predictive utility of self-report measures of this psychological construct, relatively little research has investigated the psychometric properties of the self-report scale by which it is most commonly measured – the Santa Barbara Sense of Direction scale (SBSOD, Hegarty et al., 2002) – or the broader personality correlates. The present study evaluated the factor structure of the SBSOD following administration to 12,155 individuals and situated it among prominent sources of individual differences, specifically the Big Five personality traits and intelligence. Findings suggest that the SBSOD scale has relatively high general factor saturation, and that a considerable portion of the variance in SBSOD scores is explained by other personality traits, including Conscientiousness (r = 0.33), Intellect (r = 0.27), Emotional Stability (r = 0.26), and Extraversion (r = 0.23). Cognitive ability was less highly correlated with SBSOD scores when measured at the level of general intelligence (r = 0.11) and in terms of mental rotation ability (r = .07). Recommendations are given for revision of the SBSOD scale based on item-level analyses.     

Intelligence,social class of origin,childhood behavior disturbance and education as predictors of status attainment in midlife in men: The Aberdeen Children of the 1950s study

In a birth cohort of 6281 men from Aberdeen, Scotland, social class of origin, childhood intelligence, childhood behavior disturbance and education were examined as predictors of status attainment in midlife (46 to 51 years). Social class of origin, intelligence and behavior disturbance were conceptualized as correlated predictors, whose effects were hypothesized to be partially mediated by educational qualifications. A structural equation model using Full Information Maximum Likelihood estimation confirmed that education had the strongest direct effect on status attainment at midlife. Furthermore, education partially mediated the effects of social class of origin and childhood intelligence, and fully mediated the effects of behavior disturbance on status attainment. Social class of origin, childhood intelligence and behavior disturbance were strongly inter-correlated. After controlling for these associations, educational and social status attainments were influenced to a considerably greater extent by childhood intelligence than by social class of origin.     

Childhood intelligence predicts premature mortality: Results from a 40-year population-based longitudinal study

Childhood intelligence has been shown to predict mortality risk in adulthood. This relation has never been investigated in a Central European country with universal health care. The present study investigated whether childhood intelligence predicts mortality risk across 40 years in Luxembourg. 2543 participants completed an intelligence test at age 12 in 1968, and the mortality rate in this sample until 2008 was recorded. Our results showed that higher childhood intelligence predicted a lower risk for mortality, even when childhood socioeconomic status was controlled for. This effect was strongest in men belonging to the group of the lowest 20% in intelligence. These results indicate that even universal access to health care cannot fully offset the cumulative effects of intelligence on mortality.     

Head flexion and different walking speeds do not affect gait stability in older females

Head flexion is destabilizing in older individuals during quiet stance, yet the effect head flexion has on gait is not known. The study examined whether head flexion and gait parameters were altered when walking freely and fixed to a visual target, at different walking speeds. 15 young (23 ± 4 years) and 16 older (76 ± 6 years) healthy females walked at three different walking speeds (slow, comfortable, and fast) under two visual conditions (natural and fixed [focusing on a visual target set at eye level]). Head flexion was assessed using 2D video analysis, whilst gait parameters (step length, double support time, step time, and gait stability ratio) were recorded during a 9 m flat walkway. A mixed design ANOVA was performed for each variable, with age as the between-subject factor and, visual condition and walking speed as within-subject factors. When walking freely, older displayed a greater need for head flexion between walking speeds (P < 0.05) when compared to young. Walking under fixed condition reduced head flexion at all walking speeds in the older (P < 0.05), but had no effect on the young (P > 0.05). Walking at different speeds showed no difference in head flexion when walking under either visual condition and had no effect on gait stability for both groups. Despite older displaying differences in head flexion between visual conditions, there was no effect on gait parameters. Walking speed presented trivial difference in head flexion in older females, whilst overall gait stability was unaffected by different walking speeds.     

Aggressive driving in Romania: Psychometric properties of the Driving Anger Expression Inventory

The present research verified the psychometric properties of the Driving Anger Expression Inventory (DAX; Deffenbacher, Lynch, Oetting, & Swaim, 2002) on a Romanian sample (n = 262). Exploratory factor analysis revealed a three-factor structure: Verbal and Physical Aggressive Expression (α = .86), Adaptive/Constructive Expression (α = .88) and Using the Vehicle for Aggressive Expression (α = .83). The aggressive forms of expressing anger were summed up in the Total Driving Aggressive Expression Index (α = .90). Confirmatory factor analysis supported the three factors solution, by showing a good fit into a 30 items version of the DAX. All the aggressive forms of anger expression correlated positively with each other and with trait Aggression-Hostility, while the adaptive way of expressing anger correlated negatively with them, thus supporting the convergent validity of the DAX. Age differences were identified, in that younger drivers scored higher in Using the Vehicle for Aggressive Expression scale and in Total Driving Aggressive Expression Index, while older drivers scored higher in Adaptive/Constructive Expression scale. Several directions for future research concerning the DAX are suggested. Overall, our results showed that the Romanian version of the DAX is a valid tool for assessing aggressive driving.     

Improving general intelligence with a nutrient-based pharmacological intervention

Cognitive enhancing substances such as amphetamine and modafinil have become popular in recent years to improve acute cognitive performance particularly in environments in which enhanced cognition or intelligence is required. Nutraceutical nootropics, which are natural substances that have the ability to bring about acute or chronic changes in cognition have also been gaining popularity in a range of settings and applications including the workplace, driving and in the amelioration of age related cognitive decline. Huperzine A, Vinpocetine, Acetyl-l-carnitine, Rhodiola Rosea and Alpha-lipoic Acid are popular nutritional supplements that have shown promising benefits in improving a range of biological (e.g., blood flow, anti-inflammatory, anti-oxidant, and direct neurotransmitter effects) and cognitive processes from in vitro, animal and human clinical research. We report here the first human randomized clinical trial for cognition in which we administer a combination of Huperzine A, Vinpocetine, Acetyl-l-carnitine, R. Rosea and Alpha-lipoic acid (called Ceretrophin) vs placebo. Sixty participants (40 females and 20 males, with a mean age of 45.4 years, SD = 12.6) completed either the odd or even items from the Raven Advanced Progressive Matrices (APM) at baseline and the opposite odd or even items at week 4 after consuming either the combination nootropic or placebo. A significant study visit (time) × treatment condition interaction was found: F (1, 57) = 7.279, p = 0.009, partial η² = .113, with paired samples t-tests revealing a significant improvement in mean APM score from baseline to retest (week 4) (t(34) = ? 4.045, p < .001) for the Ceretrophin? group. Improvements in APM scores could be attributed to the active intervention over the placebo, indicating that the treatment improved general intelligence. Implications for improving our understanding of the biological basis of intelligence and pharmacologically improving human cognition are discussed.     

“To g or not to g?” — Analysis of the dimensional structure of a cognitive abilities’ battery

Over the past century there has been an extensive debate in Psychology over whether intelligence structure is best represented through a single general ability, multiple specific abilities, or a hierarchical structure of abilities. This study aims at contributing to this debate through an analysis of the dimensional structure of a cognitive abilities’ battery aiming to evaluate, in combination, differentiated cognitive processes of increasing complexity (comprehension, reasoning, and problem solving) through items of different contents (verbal, numerical, and spatial). A Portuguese representative sample of 2546 adolescents enrolled in secondary education participated in the study. Confirmatory factor analyses were carried out and the results showed that: (1) the hierarchical model is the only presenting an acceptable fit to the data (RMSEA = .07; CFI = .96; TLI = .92), (2) the existence of specific factors cannot be neglected, and (3) contents of the subtests assume relevance to explain the levels of adolescents’ cognitive performance. These results are discussed taking into account the contribution of school experience for the development and differentiation of adolescents’ cognitive abilities.