Intergenerational transmission of neuropsychological executive functioning

Relationships between parent and child executive functioning were examined, controlling for the critical potential confound of IQ, in a family study involving 434 children (130 girls and 304 boys) and 376 parents from 204 community recruited families at high risk for the development of substance use disorder. Structural equation modeling found evidence of separate executive functioning and intelligence (IQ) latent variables. Mother’s and father’s executive functioning were associated with child’s executive functioning (beta = 0.34 for father–child and 0.51 for mother–child), independently of parental IQ, which as expected was associated with child’s IQ (beta = 0.52 for father–child and 0.54 for mother–child). Familial correlations also showed a significant relationship of executive functioning between parents and offspring. These findings clarify that key elements of the executive functioning construct are reliably differentiable from IQ, and are transmitted in families. This work supports the utility of the construct of executive function in further study of the mechanisms and etiology of externalizing psychopathologies.     

Are apparent sex differences in mean IQ scores created in part by sample restriction and increased male variance?

This study investigated the possibility that apparent sex differences in IQ are at least partly created by the degree of sample restriction from the baseline population. We used a nationally representative sample, the 1970 British Cohort Study. Sample sizes varied from 6518 to 11,389 between data-collection sweeps. Principal components analysis of scores obtained on four cognitive tests administered at age 10 was used to obtain estimates that we name ‘IQ’. These age-10 scores were then used to estimate the sex differences at age 10, and also among participants in the two later waves, at age 26 and 30. At age 10, there was a small but significant advantage for boys (Cohen’s d = 0.081). Boys had greater variability in these IQ scores. We then investigated how this very small male advantage at 10 changed with sample restriction. We used the same IQs obtained at age 10, but considered only those subjects who returned for data-collection sweeps at ages 26 and 30 years. Subjects returning at age 26 and 30 were more likely to be females and to have higher age-10 IQ scores. Attrition at age 30 was 28% and the male advantage in IQ scores increased by 15%. Attrition at age 26 was 43% and the male advantage in IQ scores increased by 48%. The findings underline the importance of monitoring attrition in longitudinal studies, as well as emphasising the need for representative samples in studying sex differences in intelligence. A proportion of the apparent male advantage in general cognitive ability that has been reported by some researchers might be attributable to the combination of greater male variance in general cognitive ability and sample restriction, though this remains to be tested in a sample with an appropriate mental test battery.     

Genetic influences on the overlap between low IQ and antisocial behavior in young children

The well-documented relation between the phenotypes of low IQ and childhood antisocial behavior could be explained by either common genetic influences or environmental influences. These competing explanations were examined through use of the Environmental Risk Longitudinal Twin Study 1994-1995 cohort (Moffitt & the E-Risk Study Team, 2002) of 1,116 twin pairs and their families. Children's IQ was assessed via individual testing at age 5 years. Mothers and teachers reported on children's antisocial behavior at ages 5 and 7 years. Low IQ was related to antisocial behavior at age 5 years and predicted relatively higher antisocial behavior scores at age 7 years when antisocial behavior at age 5 years was controlled. This association was significantly stronger among boys than among girls. Genetic influences common to both phenotypes explained 100% of the low IQ-antisocial behavior relation in boys. Findings suggest that specific candidate genes and neurobiological processes should be tested in relation to both phenotypes.     

A study of the greater male variability hypothesis in creative thinking in Mainland China: Male superiority exists

This study tested the greater male variability hypothesis in creative thinking with a Chinese student sample in Mainland China. The Test for Creative Thinking-Drawing Production (TCT-DP) was administered to 627 Chinese adolescent boys (n = 332) and girls (n = 295). Results using the boy/girl variance ratio (VR) generally supported the hypothesis that boys have greater variability than girls in creativity test performance. However, results using the boy/girl ratios from different regions of the creativity score distribution revealed a pattern of male superiority. While boys significantly outnumbered girls in the higher extremes, girls tended to outnumber boys in the central region and the lower extremes. Results from an analysis of the means lent further support to the findings of male superiority. Plausible explanations for greater male variability and male superiority in Mainland China are proposed. The theoretical and practical implications of the findings are discussed.     

Gender and its contribution to the prediction of cognitive abilities at 5 years

Gender-related differences in the prediction of five year-olds' cognitive abilities from measures of distal environment, proximal environment and infant test scores were examined in a random sample of 93 boys and 90 girls. Distal environmental data included maternal IQ, maternal and paternal education. Proximal environmental data included two variables derived from the Home Screening Questionnaire: the Home Questions and the Toy Checklist. The Bayley MDI was administered at age 13 months, whereas WPPSI-R was used as cognitive outcome measure at age 5 years. The relationship between paternal education and child IQ, and between proximal environmental variables and child IQ was significantly stronger for boys than for girls. The associations between proximal environment and IQ in boys, were accounted for by the distal environmental variables. Bayley MDI correlated significantly higher with girls' IQ compared to boys' IQ. Findings are discussed in terms of parental gender-differentiated socialization processes.     

Social cognitive predictors of peer acceptance at age 5 and the moderating effects of gender

In this study we examined the effects of social intelligence, empathy, verbal ability and appearance‐reality distinction on the level of peer acceptance, as well as the moderating role of gender. Participants were 98 five‐year‐old children (43 boys and 55 girls; mean age 5 years 3 months for boys and girls). Our results showed a main effect of social intelligence on peer acceptance, as well as several other effects that were moderated by gender: a significant and positive effect of verbal ability on social acceptance was found for boys; appearance‐reality distinction was found to have a positive effect on social acceptance in the case of girls; and although empathy had a significant positive effect on social acceptance for both boys and girls, this effect was more pronounced among boys. Our results suggest that abilities promoting peer acceptance are different for boys and girls.     

Investigating the predictive roles of working memory and IQ in academic attainment

There is growing evidence for the relationship between working memory and academic attainment. The aim of the current study was to investigate whether working memory is simply a proxy for IQ or whether there is a unique contribution to learning outcomes. The findings indicate that children’s working memory skills at 5 years of age were the best predictor of literacy and numeracy 6 years later. IQ, in contrast, accounted for a smaller portion of unique variance to these learning outcomes. The results demonstrate that working memory is not a proxy for IQ but rather represents a dissociable cognitive skill with unique links to academic attainment. Critically, we find that working memory at the start of formal education is a more powerful predictor of subsequent academic success than IQ. This result has important implications for education, particularly with respect to intervention.     

Prediction of toddlers’ expressive language from maternal sensitivity and toddlers’ anger expressions: A developmental perspective

Despite evidence for the importance of individual differences in expressive language during toddlerhood in predicting later literacy skills, few researchers have examined individual and contextual factors related to language abilities across the toddler years. Furthermore, a gap remains in the literature about the extent to which the relations of negative emotions and parenting to language skills may differ for girls and boys. The purpose of this longitudinal study was to investigate the associations among maternal sensitivity, children's observed anger reactivity, and expressive language when children were 18 (T1; n = 247) and 30 (T2; n = 216) months. At each age, mothers reported on their toddlers’ expressive language, and mothers’ sensitive parenting behavior was observed during an unstructured free-play task. Toddlers’ anger expressions were observed during an emotion-eliciting task. Using path modeling, results showed few relations at T1. At T2, maternal sensitivity was negatively related to anger, and in turn, anger was associated with lower language skills. However, moderation analyses showed that these findings were significant for boys but not for girls. In addition, T1 maternal sensitivity and anger positively predicted expressive language longitudinally for both sexes. Findings suggest that the relations between maternal sensitivity, anger reactivity and expressive language may vary depending on the child's developmental stage and sex.     

Item-response theory modeling of IQ gains (the Flynn effect) on crystallized intelligence: Rodgers' hypothesis yes,Brand's hypothesis perhaps

Potential explanations for generational intelligence test score gains continue to be subject to intense debate and scrutiny in the scientific community. However, the explanatory value of some of the proposed causes remains difficult to determine, since only little empirical evidence is available. To clarify the role of two scarcely investigated theories accounting for the Flynn effect, this study set out to examine the role of changing test-taking behavior (Brand's hypothesis) and of a narrowing of the IQ ability distribution (Rodgers' hypothesis). Archival records of crystallized intelligence test performance over a time-span of 17 years of a large number of psychiatric inpatients and outpatients in Austria were investigated (N = 5445; 1978–94). This sample was particularly suitable to investigate our hypotheses since participants were under no pressure to perform which makes observed changes in test taking behavior attributable to personal style and ability rather than differential performance in pressure situations. Analytical approaches of both classical test theory and item response theory (IRT) yielded gains of 1.0 to 2.4 IQ points per decade. Test-taking behavior indicative of guessing and decreasing population IQ variability appeared to contribute both to IQ test score gains. IRT-based analyses showed that gains were largely preserved when controlling for highest educational qualification, while the test instrument showed measurement invariance between cohorts. However, IRT-based results also suggested that changes in test-taking behavior might not necessarily reflect increased guessing, but item drift instead. In all, this evidence emphasizes better performance of individuals of the lower tail of the IQ ability distribution in more recent years as one important contributing factor for generational IQ test score gains.     

Does the Animal Fun program improve motor performance in children aged 4–6 years?

The Animal Fun program was designed to enhance the motor ability of young children by imitating the movements of animals in a fun, inclusive setting. The efficacy of this program was investigated through a randomized controlled trial using a multivariate nested cohort design. Pre-intervention scores were recorded for 511 children aged 4.83 years to 6.17 years (M = 5.42 years, SD = 3.58 months). Six control and six intervention schools were compared 6 months later following the intervention, and then again at 18 months after the initial testing when the children were in their first school year. Changes in motor performance were examined using the Bruininks-Oseretsky Test of Motor Proficiency short form. Data were analyzed using multi-level-mixed effects linear regression. A significant Condition × Time interaction was found, F(2, 1219) = 3.35, p = .035, demonstrating that only the intervention group showed an improvement in motor ability. A significant Sex × Time interaction was also found, F(2, 1219) = 3.84, p = .022, with boys improving over time, but not girls. These findings have important implications for the efficacy of early intervention of motor skills and understanding the differences in motor performance between boys and girls.     

The relationship between IQ, social class and EEG findings in healthy children investigated by child-psychiatric methods

Abstract.— 222 children aged between 4.5 and 16.5 years. who were found to be normal by strict somato-neuro-logical criteria, were investigated by EEG and by child-psychiatric methods. Intelligence tests were performed according to WISC. The mean intelligence quotient amounted to 116.3± 12.4 in boys and 116.6± 14.1 in girls. Child-psychiatric findings deviating from the strictly normal occurred in 30 children significantly more frequently in social class III compared to I and 11. There was no relationship of significance between IQ and social group. No relevant relationship was found between IQ and psychiatric variables, nor between IQ and EEG-findings. The absence of the normal fixed relationship between IQ and social group is a notable finding, as is also the high average IQ. The strict normal criteria may have contributed to the exclusion of individuals with lesions and thus diminished factors having an inhibitory effect of the development of intelligence.     

Ego development and chronic illness in adolescents

To examine the effects of chronic illness on the psychological growth process known as ego development, scores were compared on the Loevinger Sentence Completion Test for 36 teens (16 boys, 20 girls) with chronic illness and 50 teens (16 boys, 34 girls) without chronic illness. Their ages ranged from 13 to 21 years, with a mean of 17.4 years. Most were Black (37%) or Hispanic (41%) and lived in poor or working-class neighborhoods. When age, sex, and Peabody Picture Vocabulary Test (PPVT) scores were controlled in multiple regression analyses, no direct association between ego development stage and presence of chronic illness, severity of illness, age at onset, or duration of illness was found. Analysis of the chronically ill group alone revealed a significant PPVT X Severity interaction, indicating that ego development in chronically ill teens is lower when illness is more severe and verbal IQ is higher.     

Aggression and prosocial behaviors in social conflicts mediating the influence of cold social intelligence and affective empathy on children's social preference

This study proposes a model in which aggressive and prosocial behaviors exhibited in social conflicts mediate the influence of empathy and social intelligence to children's social preference by same‐sex peers. Data were obtained from kindergarten to the end of the first grade. The sample yielded 117 Spanish children (64 girls and 53 boys) with a mean age of 62.8 months (SD = 3.3) at the beginning of the study. For boys, affective empathy contributed to boys’ social preference through a decrease in physical aggression as responses to social conflict. For girls, affective empathy had an indirect effect on girls’ preference by increasing assistance to others in their conflicts. No mediating effect in the contribution of social intelligence on girls’ social preference was detected. Our results suggest that, only for girls, cold social intelligence can promote both indirect aggression (coercive strategic that do not leave social preference, at least at these ages) and behaviors that lead social preference (such as prosocial behaviors).     

Gender differences on the WPPSI, the WISC-R, and the WPPSI-R

The WPPSI, WISC-R, and WPPSI-R were administered in a counterbalanced design to 72 children between the ages of 5 years, 10 months, 16 days, and 6 years, 7 months, and 15 days to test the hypothesis that mean verbal IQs on these scales would be higher for boys than for girls. Results indicated that the mean verbal IQs for boys were significantly (p<.05) higher than those for girls on all three scales. Also, significant (p<.05) differences favoring boys were found onVocabulary andComprehension subtests on all three scales. These differences are probably a peculiarity of these scales and may not need any elaborate theoretical explanation. However, clinical uses of verbal and performance IQ discrepancies may not justifiably ignore the examinees’ gender.     

Dietary patterns and intelligence in early and middle childhood

The association between intelligence and diet at 3.5 and 7 years was examined in 591 children of European descent. Approximately half of the children were born small-for-gestational age (birth weight ≤ 10th percentile). The relationship between IQ and diet (measured by food frequency) was investigated using multiple regression analyses. Eating margarine at least daily was associated with significantly lower IQ scores at 3.5 years in the total sample and at 7 years in SGA children. For all children, eating the recommended daily number of breads and cereals was associated with significantly higher IQ scores at 3.5 years, and those who ate fish at least weekly had significantly higher IQ scores at 7 years than those who did not. The consumption of fish, breads and cereals commeasurable with nutritional guidelines may be beneficial to children's cognitive development. In contrast, consuming margarine daily was associated with poorer cognitive functioning. Further research is needed to identify the nutrients that may underlie this association.     

Gender differences on the WPPSI,the WISC-R,and the WPPSI-R

The WPPSI, WISC-R, and WPPSI-R were administered in a counterbalanced design to 72 children between the ages of 5 years, 10 months, 16 days, and 6 years, 7 months, and 15 days to test the hypothesis that mean verbal IQs on these scales would be higher for boys than for girls. Results indicated that the mean verbal IQs for boys were significantly (p<.05) higher than those for girls on all three scales. Also, significant (p<.05) differences favoring boys were found onVocabulary andComprehension subtests on all three scales. These differences are probably a peculiarity of these scales and may not need any elaborate theoretical explanation. However, clinical uses of verbal and performance IQ discrepancies may not justifiably ignore the examinees’ gender.     

SMS length and function: A comparative study of 13- to 18-year-old girls and boys

ObjectiveThe use of SMS messaging has grown rapidly over the past decade. Up until now, most French-language studies have focused on one predominant SMS characteristic: spelling. The goal of this paper is to extend previous research topics so as to include new dependant variables such as message length and message functions.MethodA corpus of 1131 SMSes produced in a natural environment by teenage French speakers was analysed. This group was made up of teenage girls and boys between the ages of 13 and 18 who reported frequent usage of SMS messaging over an extended period of time. Did these SMS exchanges confirm stereotypes regarding gender differences? That is, did girls produce longer messages than boys? Did girls send more messages with a relational function than with an informational function, while boys did just the opposite?ResultsThe results led to a mitigation of these stereotypes. Girls did produce longer messages than boys. However, this only occurred when the girls were 15–16 years of age and had a long-standing and frequent practice of SMS usage. Regarding functions, girls’ messages more often had a relational function than an informational one, but again, only in girls who were 15–16 years of age and had been SMSing frequently for a long period of time. In boys, it took until 17–18 years of age for the same result to appear. More than a gender difference, these results emphasized a discrepancy in the developmental curves of girls and boys, girls being more precocious than boys.     

Children's cognitive ability from 4 to 9 years old as a function of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence

This study examined the effects of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence on children's cognitive ability. Gender and age were examined as moderators of potential cocaine exposure effects. The Stanford-Binet IV intelligence test was administered to 231 children (91 cocaine exposed, 140 unexposed) at ages 4, 6, and 9 years. Neonatal medical risk and other prenatal exposures (alcohol, cigarettes, and marijuana) were also examined for their unique effects on child IQ. Mixed models analysis indicated that prenatal cocaine exposure interacted with gender, as cocaine-exposed boys had lower composite IQ scores. Age at assessment did not moderate this relation, indicating that cocaine-exposed boys had lower IQs across this age period. A stimulating home environment and high maternal verbal IQ also predicted higher composite IQ scores. Cocaine-exposed boys had lower scores on the Abstract/Visual Reasoning subscale, with trends for lower scores on the Short-Term Memory and Verbal Reasoning subscales, as exposure effects were observed across domains. The findings indicate that cocaine exposure continues to place children at risk for mild cognitive deficits into preadolescence. Possible mechanisms for the Exposure x Gender interaction are discussed.     

Intra-individual stability of neuromotor tasks from 6 to 18 years: a longitudinal study

This study investigates the intra-individual stability of the speed of several motor tasks and the intensity of associated movements in 256 children (131 girls, 125 boys) from the Zurich generational study using the Zurich neuromotor assessment battery (ZNA) over a 12-year period from the age of 6 to 18 years. The stability was assessed by correlograms of standard deviation scores calculated from age- and gender-adjusted normative values and compared with standing height and full scale intelligence quotient (IQ). While motor tasks of hand, finger and foot (HFT) and contralateral associated movements (CAM) exhibited a moderate stability (summary measure as correlation coefficients between two measurements made 4 years apart: .61 and .60), other tasks (dynamic balance, static balance and pegboard) were only weakly stable (.46, .47 and .49). IQ and height were more stable than neuromotor components (.72 and .86). We conclude that the moderately stable HFT and CAM may reflect “motor traits”, while the stability of the pegboard and balance tasks is weaker because these skills are more experience related and state-dependent.     

The Flynn effect in South Africa

This is a study of secular score gains in South Africa. The findings are based on representative samples from datasets utilized in norm studies of popular mainstream intelligence batteries such as the WAIS as well as widely used test batteries which were locally developed and normed in South Africa. Flynn effects were computed in three ways. First, studies where two different groups take the same test, with several years in between, using representative or comparable samples were used. Second, studies where the same group takes two different test batteries at a specific time were used. Third, the score differences between English- and Afrikaans-speaking Whites in South Africa in the 20th century were compared. The Flynn effect in White groups in South Africa is somewhat smaller than the Flynn effect in Western, industrialized countries (total N = 6534), and the Flynn effect in Indian groups is substantially smaller (total N = 682). Non-verbal IQ scores surpassed increases in verbal IQ scores. The findings from English- and Afrikaans-speaking Whites evidence a leveling out of differences in score gains over the 20th century (total N = 79,310). A meta-regression analysis showed no clear support for the moderators a) method used for computing the Flynn effect gain, b) type of test battery, c) time span, d) quality of the sample, and e) average age of sample.