Confusing developmental and individual differences

T. Globerson (1985, Developmental Review, 5, 261–273) compared the relative effects of an individual difference variable field dependency (FD/I) with a developmental variable (age) on a measure of M-capacity, in an analysis of variance (ANOVA) design. Age is a highly significant effect and the sum of squares associated with this factor accounts for 66% of the variance in M-capacity. FD/I is not significant and accounts for less than 1% of the variance in M-capacity. This is interpreted as indicating that M-capacity is a purely developmental phenomenon showing negligible individual differences. This paper argues that this result is an inevitable artifact of the experimental design. Further, the design is a common one in developmental psychology, and its dangers are largely unrecognized. The main problems concern (1) dichotomizing a continuous variable and treating the dichotomy as two levels of a factorial variable, (2) drawing inferences about the size of relationship between the continuous variable and the dependent variable on the basis of the variance accounted for by the factorial variable in the ANOVA, (3) differential reliability of measures of the independent variables, and (4) selective control of the sampling of the independent variables. These issues are explored in a simulation of Globerson's data and in an analogous analysis of data relating age and height, as independent variables, with weight as a dependent variable.     

Effects of IQ on Executive Function Measures in Children with ADHD

The present study compared children with Attention-Deficit Hyperactivity Disorder (ADHD) and controls on a selected set of clinical measures of executive function (EF). A total of 92 children (51 ADHD, 41 control), ages 6-16, completed measures chosen from a larger neuropsychological battery to illustrate diverse components of the EF construct (planning, inhibitory control, response preparation, memory search). The selected measures were moderately correlated with one another, and moderately correlated with IQ. After controlling for age, sex, presence of learning disability (LD), ADHD, and IQ test version, Full Scale IQ was significantly related to four of the five selected EF measures. A second analysis showed group differences on the EF measures at different IQ levels. After covarying for age, there was a significant multivariate effect for IQ level (average, high average, superior) and a significant multivariate interaction between group (ADHD vs. control) and IQ level. Three of the five selected EF measures showed significant univariate group effects (controls performing better than ADHD) at the average IQ level; however, there were no significant group differences between children with ADHD and controls at high average or superior IQ levels. These results suggest that clinical measures of EF may differ among children with ADHD and controls at average IQ levels, but there is poorer discriminatory power for these measures among children with above average IQ.     

Effects of IQ on executive function measures in children with ADHD.

The present study compared children with Attention-Deficit Hyperactivity Disorder (ADHD) and controls on a selected set of clinical measures of executive function (EF). A total of 92 children (51 ADHD, 41 control), ages 6-16, completed measures chosen from a larger neuropsychological battery to illustrate diverse components of the EF construct (planning, inhibitory control, response preparation, memory search). The selected measures were moderately correlated with one another, and moderately correlated with IQ. After controlling for age, sex, presence of learning disability (LD), ADHD, and IQ test version, Full Scale IQ was significantly related to four of the five selected EF measures. A second analysis showed group differences on the EF measures at different IQ levels. After covarying for age, there was a significant multivariate effect for IQ level (average, high average, superior) and a significant multivariate interaction between group (ADHD vs. control) and IQ level. Three of the five selected EF measures showed significant univariate group effects (controls performing better than ADHD) at the average IQ level; however, there were no significant group differences between children with ADHD and controls at high average or superior IQ levels. These results suggest that clinical measures of EF may differ among children with ADHD and controls at average IQ levels, but there is poorer discriminatory power for these measures among children with above average IQ.     

Genetic and environmental influences on executive functions and intelligence in middle childhood

Executive functions (EFs) and intelligence (IQ) are phenotypically correlated. In twin studies, latent variables for EFs and IQ display moderate to high heritability estimates; however, they show variable genetic correlations in twin studies spanning childhood to middle age. We analyzed data from over 11,000 children (9- to 10-year-olds, including 749 twin pairs) in the Adolescent Brain Cognitive Development (ABCD) Study to examine the phenotypic and genetic relations between EFs and IQ in childhood. We identified two EF factors—Common EF and Updating-Specific—which were both related to IQ (rs = 0.64–0.81). Common EF and IQ were heritable (53%–67%), and their genetic correlation (rG = 0.86) was not significantly different than 1. These results suggest that EFs and IQ are phenotypically but not genetically separable in middle childhood, meaning that this phenotypic separability may be influenced by environmental factors.     

Effects of the EXAT neuropsychological multilevel intervention on behavior problems in children with executive function deficits

This is a clinical intervention study of children with executive function (EF ) deficits. A neuropsychological multimodal group intervention called EXAT (rehabilitation of EX ecutive function and AT tention) was developed at the Psychology Clinic of the University of Tampere. Based on the principles of neuropsychological rehabilitation and behavioral modification, EXAT combines child group training, parent training, and teacher consultations. The aims of this study were to investigate behavior problems before and after the intervention in children attending EXAT and in controls, and to compare intervention effects in hyperactive, inattentive, and EF subgroups based on the primary deficit described in the referral. The participants were 86 children (6–12 years) with a mean IQ of 91.4 attending EXAT and 45 controls. The participants’ parents and teachers completed the Conners’ Rating Scales‐Revised. In addition, the Strengths and Difficulties Questionnaire was completed by the parents attending EXAT . The parents reported statistically significant decreases with medium effect sizes for the CPRS ‐R subscales for impulsivity, hyperactivity, and oppositional behavior. In the controls within the same time interval, there was increase in restless and impulsive behavior, and a decrease in total problems. The teachers reported positive changes after the intervention in ADHD symptoms and anxiousness/shyness, but the effects sizes were small. The intervention effects were larger in the hyperactive subgroup. Positive intervention effects were related to a younger age, lower IQ , and simultaneous learning support. In conclusion, EXAT – a structured multilevel group intervention – has positive effects on children's behavior regulation skills by decreasing impulsivity and restless behavior.     

Raising the IQ: The Ramey and Haskins study

The Ramey and Haskins intervention experiment succeeded in producing IQ gains at three years of age averaging about one standard deviation in young children who were selected for being at risk for subnormal intellectual development. The study is examined in terms of its consistency with other findings, the heritability of IQ, the g aspect of IQ, the simplex pattern of longitudinal interage mental test score correlations, mother-child IQ correlations, and criteria for establishing educationally and socially significant gains in intelligence defined as g rather than as a score on a particular test. Narrow transfer of training from cognitive intervention techniques to IQ test performance in early childhood, rather than enhancement of the g factor itself, is hypothesized as a cause of the typical fadeout of early IQ gains in later childhood.     

Executive and Attention Functioning Among Children in the PANDAS Subgroup

Evidence from past studies indicates that adults and children with Obsessive-Compulsive Disorder (OCD) and Tourette syndrome (TS) experience subtle neuropsychological deficits. Less is known about neuropsychological functioning of children and adolescents with a symptom course consistent with the PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infection) subgroup of OCD and tics. To provide such information, we administered three tests of attention control and two of executive function to 67 children and adolescents (ages 5–16) diagnosed with OCD and/or tics and a symptom course consistent with the PANDAS subgroup and 98 healthy volunteers (HV) matched by age, sex, and IQ. In a paired comparison of the two groups, the PANDAS subjects were less accurate than HV in a test of response suppression. Further, in a two-step linear regression analysis of the PANDAS group in which clinical variables were added stepwise into the model and in the second step matching variables (age, sex, and IQ) were added, IQ emerged as a predictor of performance on this task. In the same analysis, ADHD diagnosis and age emerged as predictors of response time in a continuous performance task. Subdividing the PANDAS group by primary psychiatric diagnosis revealed that subjects with TS or OCD with tics exhibited a longer response time compared to controls than subjects with OCD only, replicating previous findings within TS and OCD. This study demonstrates that children with PANDAS exhibit neuropsychological profiles similar to those of their primary psychiatric diagnosis.     

Effects of Abacus training on the intelligence of Sudanese children

The effects of Abacus training in mental computation on intelligence assessed with the standard progressive matrices (SPM) was investigated in a sample of 3185 children aged between 7 and 11 years in Sudan. The sample was divided into two groups matched for scores on the SPM, sex, age and urbanization. The experimental group was given an intensive Abacus program training for two hours per week for 34 weeks. The control group did not receive any training. Following the end of the training the control and the experimental groups were retested with the SPM. Controlling for practice effects, the experimental group gained a statistically significant 7.11 IQ points attributable to the training. The experimental group also performed significantly faster following training. The results suggest that the introduction of a greater emphasis on problem solving skills in Sudanese schools may be expected to increase general intelligence.     

Moderators of Parent Training for Disruptive Behaviors in Young Children with Autism Spectrum Disorder

We conducted a 6 month, randomized trial of parent training (PT) versus a parent education program (PEP) in 180 young children (158 boys, 22 girls), ages 3–7 years, with autism spectrum disorder (ASD). PT was superior to PEP in decreasing disruptive and noncompliant behaviors. In the current study, we assess moderators of treatment response in this trial. Thirteen clinical and demographic variables were evaluated as potential moderators of three outcome variables: the Aberrant Behavior Checklist-Irritability subscale (ABC-I), Home Situations Questionnaire (HSQ), and Clinical Global Impressions-Improvement Scale (CGI-I). We used an intent-to-treat model and random effects regression. Neither IQ nor ASD severity moderated outcome on the selected outcome measures. Severity of Attention Deficit Hyperactivity Disorder (ADHD) and anxiety moderated outcomes on the ABC-I and HSQ. For instance, there was a 6.6 point difference on the ABC-I between high and low ADHD groups (p?=?.05) and a 5.3 point difference between high and low Anxiety groups (p?=?.04). Oppositional defiant disorder symptoms and household income moderated outcomes on the HSQ. None of the baseline variables moderated outcome on the CGI-I. That IQ and ASD symptom severity did not moderate outcome suggests that PT is likely to benefit a wide range of children with ASD and disruptive behavior.     

Evolution of the wealth gap in child development and mediating pathways: Evidence from a longitudinal study in Bogota,Colombia

Large gaps in cognition and language on the Bayley‐III between the top and bottom household wealth quartiles in 1,330 children aged 6–42 months in a representative sample of low‐ and middle‐income families in Bogota were previously shown. Maternal education and the home environment mediated these wealth effects, whereas height‐for‐age mediated a small amount of the language deficit only. At ages 6–8 years, we relocated 72% of the children and assessed their IQ on the WISC‐V, school achievement, and behavior to investigate the evolution of the wealth gaps and potential mediators. The wealth gap in IQ at 6–8 years was significantly larger than that in a factor combining Bayley‐III language and cognition at 6–42 months; whereas the gap in achievement was larger but not significantly. Moreover, in cross‐sectional analysis, the IQ gap increased from 6 to 8 years reaching over 1 SD. In contrast, the gap in behavior was not significant in either childhood stage. Parental education and early home environment remained major mediators of the wealth gap in IQ and achievement at 6–8 years; later home environment and attending private education also had an effect; and early height‐for‐age was no longer significant. The home environment partly mediated the effect of parental education on wealth. All mediators combined explained most of the variance in the wealth gap; the remaining gaps being not significant. Results highlight the importance of the early home environment and suggest that interventions focusing on that should have long‐term benefits. Also, continued intervention through to 8 years may be desirable. A video abstract of this article can be viewed at https://youtu.be/_U53iXNww3I .     

A Comparison of Children with Epilepsy to an Age- and IQ-Matched Control Group on the Children's Memory Scale

Past research has found that children with epilepsy exhibit decreased memory skills. In addition, some studies have found that children with epilepsy obtain significantly lower IQ scores than controls. In an effort to examine whether children with epilepsy have specific memory weaknesses versus global cognitive difficulties, the present study compared the performance of 62 children (age range = 6–16 years). Thirty-one children with epilepsy were compared to 31 age- and IQ-matched controls on the Children's Memory Scale (CMS) to determine whether differences in memory skills persist when IQ is matched. An independent t-test comparing index and scaled scores was performed. The results indicated that with the exception of the Word Pairs subtest (p < .01), children with epilepsy did not differ significantly on the CMS subtests when IQ was matched. This suggests that list-learning paradigms may be particularly sensitive to memory impairments in children with epilepsy and/or that children with epilepsy have more global cognitive impairments.     

Unique Contributions of Positive Schemas for Understanding Child and Adolescent Life Satisfaction and Happiness

Much research has examined negative cognitive schemas as associates of psychopathology. Although some research has established relations between positive cognitive schemas and psychopathology, little research has examined positive cognitive schemas in the context of well-being among children and adolescents. In the current study, contributions of positive schemas to two indicators of well-being, namely happiness and life satisfaction, were examined. Specifically we examined how positive schemas predict well-being beyond negative schemas, whether age and gender moderate the relations between positive schemas and well-being, and the contributions of specific positive schema themes to well-being. 282 child and adolescent boys (n = 122) and girls (n = 160) aged 8–18 (M = 13.37, SD = 2.18), completed measures of positive schemas, negative schemas, life satisfaction, and happiness. Results indicated that positive schemas related to life satisfaction and happiness beyond negative schemas, supporting the importance of examining positive schemas in models of well-being. Positive schemas were more strongly tied to happiness in older adolescents versus younger children, but the relations between positive schemas and life satisfaction did not vary as a function of age. Gender effects indicate that the relation between positive schemas and life satisfaction and happiness was stronger for females than for males. When the relative contributions of positive schema themes (i.e., trust, worthiness, optimism, success, self-efficacy) were explored in the prediction of life satisfaction and happiness, worthiness emerged as the strongest predictor. Results emphasize the importance of considering positive schemas in models of well-being among children and adolescents.     

Epidemiological investigation of mental disorders of children in Reykjavík, Iceland

Abstract.— A representative sample of 1100 children aged 5–15 years in Reykjavík was investigated with the WISC test, the Rorschach test, and an extensive semistructured interview with the mothers. The purpose of the investigation was to estimate the frequency of mental disorders in the population of children in Reykjavík, and their socioeconomic and educational correlates. The percentage of severely disordered children for the different mental health variables ranged from 11.8% to 30.8%. No significant differences were found as to age and sex. Most clearly associated with mental health were the parents' educational level, occupational status of father, the maternal attitudes of warmth and emotional involvment and the child's IQ and school achievement.     

Assessment of perception of morphed facial expressions using the Emotion Recognition Task: Normative data from healthy participants aged 8–75

The ability to recognize and label emotional facial expressions is an important aspect of social cognition. However, existing paradigms to examine this ability present only static facial expressions, suffer from ceiling effects or have limited or no norms. A computerized test, the Emotion Recognition Task (ERT), was developed to overcome these difficulties. In this study, we examined the effects of age, sex, and intellectual ability on emotion perception using the ERT. In this test, emotional facial expressions are presented as morphs gradually expressing one of the six basic emotions from neutral to four levels of intensity (40%, 60%, 80%, and 100%). The task was administered in 373 healthy participants aged 8–75. In children aged 8–17, only small developmental effects were found for the emotions anger and happiness, in contrast to adults who showed age‐related decline on anger, fear, happiness, and sadness. Sex differences were present predominantly in the adult participants. IQ only minimally affected the perception of disgust in the children, while years of education were correlated with all emotions but surprise and disgust in the adult participants. A regression‐based approach was adopted to present age‐ and education‐ or IQ‐adjusted normative data for use in clinical practice. Previous studies using the ERT have demonstrated selective impairments on specific emotions in a variety of psychiatric, neurologic, or neurodegenerative patient groups, making the ERT a valuable addition to existing paradigms for the assessment of emotion perception.     

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.     

Age and ability effects on test scores reflecting M-capacity, learning and cognitive style

Eight- and ten-year-old children of low and average ability were given four tests, one of which was developed by Pascual-Leone (1970) as a relatively pure measure of mental capacity (M-capacity) as conceived in his neo-Piagetian model. The remaining tests confounded knowledge base and cognitive style (field dependence/independence) with M-capacity to varying degrees. Age and ability effects were found, but were invariant over tests. This contradicts Globerson’s (1983) predictions for the hierarchy of tests used. Possible reasons for an apparent discrepancy between Globerson’s results and those of the present study are discussed.     

Association between restricted and repetitive behaviors and nonverbal IQ in children with autism spectrum disorders.

The present study explored the relationship between nonverbal IQ and restricted and repetitive behaviors (RRBs) in 830 children with Autism Spectrum Disorders. The role of chronological age as a moderator of this relationship was also investigated. For many behaviors, there was a significant interaction between nonverbal IQ and chronological age, such that nonverbal IQ (NVIQ) was more strongly related to the prevalence of RRBs in older children. For the majority of such behaviors (e.g. repetitive use of objects, hand and finger mannerisms), RRB prevalence was negatively associated with NVIQ. However, the prevalence of certain behaviors (e.g. circumscribed interests) showed positive relationships with NVIQ, which provides some support for the idea of different classes of RRBs. For the severity of different RRBs, there were several significant effects for age and NVIQ, but few interactions.     

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.