A Two-Year Longitudinal Study of Neuropsychological and Cognitive Performance in Relation to Behavioral Problems and Competencies in Elementary School Children

Despite interest in early neuropsychological status as a possible contributor to children's behavioral development, prospective longitudinal investigations of neuropsychological measures in relation to later behavioral outcomes in childhood are few. A 2-year longitudinal study in a nonselected childhood sample is reported. The study tested the influence of early neuropsychological performance (verbal fluency, mental inhibitory control, and visual spatial ability) on later childhood behavioral problems and social competency. Regular education children (n = 235) were assessed at three time points 1 year apart. To control for autocorrelation of outcome measures, Time 1 behavior was partialed while testing the effects of Time 1 neuropsychological scores on Time 3 outcome. To control for autocorrelation of neuropsychological scores, Time 2 scores were partialed while testing the predictive effect of Time 1 scores on Time 3 outcome. Both sets of regression models suggested modest but statistically significant effects for inhibitory control and verbal fluency, but not IQ, reading, or visual spatial ability, on behavioral outcome. Study results are consistent with a modest causal effect of selected neuropsychological skills on later behavioral adjustment. The findings support theories that implicate subtle neuropsychological dysfunction in the development of behavioral problems in childhood.     

A home-based approach to understanding the effect of spatial autocorrelation on seat belt non-use

Roadside observations indicate that seat belt use rates are often spatially correlated with nearby areas. However, very few studies have examined the effects of spatial autocorrelation on seat belt use. This study used exploratory spatial data analysis (ESDA) to explore spatial autocorrelation in Tennessee, which has a lower seat belt use than the United States national average. We geocoded home-addresses of vehicle occupants involved in traffic crashes between 2014 and 16 (n = 1,251,901) and projected them to the census tract corresponding to their home address. This projection reveals information about the spatial distribution of seat belt non-use and socioeconomics of the areas surrounding the crash victim's home. The presence of highly spatially correlated observations (i.e., a significant positive Moran’s I) suggests that seat belt non-use is not produced solely by the internal structural factors represented in the non-spatial models. ESDA reveals a distinctive regional imprint for spatial autocorrelation, in which Southern-metropolitan areas’ (Southern-MPOs) in Tennessee census tracts have higher than average seat belt non-use compared to Non-Southern-MPOs (16% vs. 9%). The spatial error model was suitable for Non-Southern-MPOs, whereas the spatial lag model was more suitable for Southern MPOs. Comparison of the estimated models indicates that in the Non-Southern MPOs, percentage of the White population, percentage of the population with Bachelor's degree, median household income, vehicle ownership, and population density are significant predictors of seat belt non-use. On the other hand, median household income, vehicle ownership, and percentage of population aged between 16 and 42 years old predict seat belt non-use in Southern MPOs. The study results could be used to identify seat belt non-use clusters at the state level and identify seat belt non-use hot zones. Furthermore, this analysis indicates that the relationship between demographic variables and seat belt non-use varies across regimes. Failing to consider the spatial regimes in the analysis would lead to falsely prioritizing groups prone to seat belt non-use.     

National intelligence and suicide rate across Europe: an alternative test using educational attainment data

National mean scores on a historical knowledge test (taken as a proxy for intelligence), stemming from representative samples of male (and female) 9th-grade school students from 26 European countries in a 1999 report by Wilberg and Lynn, were significantly positively associated with the national male (and female) suicide rates, independent of the general quality-of-living conditions in these countries. This finding replicates previous evidence from cross-national studies (by Lester and by Voracek), of a correspondence of higher national IQ to higher suicide rates, with an alternative measure of national IQ that is independent of the national IQ estimates recently published by Lynn and Vanhanen which have been used in prior studies.     

Sex differences in spatial cognition, computational fluency, and arithmetical reasoning

Alternative explanations for the male advantage in arithmetical reasoning, as measured by the ability to solve complex word problems, include a male advantage in spatial cognition and a male advantage in computational fluency. The current study was designed to test these competing hypotheses. To this end, 113 male and 123 female undergraduates were administered arithmetical computations and arithmetical reasoning tests, along with an IQ test and a test of spatial cognition. There was no sex difference on the IQ test, but males showed significantly higher mean scores on the arithmetical computations, arithmetical reasoning, and spatial cognition measures. A series of structural equation models indicated that individual differences in arithmetical reasoning were related to individual differences in IQ, spatial abilities, and computational fluency. Moreover, the results suggested that the male advantage in arithmetical reasoning is mediated by the male advantages in both computational fluency and spatial cognition.     

Expanding variance and the case of historical changes in IQ means: a critique of Dickens and Flynn (2001)

The Flynn effect is the rise in mean IQ scores during the 20th century, amounting to about 0.33 IQ points per year. Many theoretical explanations have been proposed, though none are universally accepted. W. Dickens and J. R. Flynn's (2001) new approach explains the large IQ changes by means of recursive models of IQ growth. A salient feature of their models is that IQ phenotypes and their supportive environments are correlated; in addition, environmental effects can rebound on phenotypic IQ to increase or lower IQ. In this critique, the authors examine an empirical challenge to their models, which typically imply large changes in IQ variance. However, the historical rise in IQ mean level has not been accompanied by substantial variance changes, a finding inconsistent with the properties of the proposed model.     

Analysis of WAIS-IV index score scatter using significant deviation from the mean index score

The Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) does not include verbal IQ and performance IQ scores, as provided in previous editions of the scale; rather, this edition provides comparisons among four index scores, allowing analysis of an individual's WAIS-IV performance in more discrete domains of cognitive ability. To supplement the pairwise index score comparisons included in the WAIS-IV manuals, this article describes the use of the mean of the four index scores (the average index score) as a baseline for analyzing index score variability and as a method for identifying strengths and weaknesses within an individual's index score pattern. Davis's formula was used to calculate critical values for the identification of index scores with a statistically significant difference from the average index score. Subsequent analysis of the WAIS-IV normative sample indicates that variability in performance at the index score level is not uncommon in the general population. More than 70% of individuals in the normative sample have at least one index score that differs significantly from their mean index score. This variability in index score performance appears to have little relationship to age or gender, but it is strongly related to the full-scale IQ.     

The determinants of parents' beliefs about the intelligence their children: A study from Hong Kong

One hundred and ninety‐three Hong Kong parents (mean age 42.2 years) were given a structured interview / questionnaire concerning their own and their children's self‐estimated overall and multiple intelligence. Previous research suggested that males tend to give higher overall “g” estimates to their children and themselves than do females, as well as higher scores on mathematical and spatial intelligence (Furnham, 2001). Further, studies in the West suggest that parents think their children are significantly brighter than they are and that their sons are brighter than their daughters. Estimates were lower than those found in Western populations but, even so, males rated their own mathematical and spatial intelligence higher than did females. Hong Kong Chinese parents did not think their sons were brighter than their daughters. The seven multiple intelligences factored into three clear factors for self and children, and regressions indicated that it was “academic” intelligence (verbal, mathematical, spatial) that was most “g” loaded. The child's age and the self‐rated overall IQ of both the parents were the best predictors of the child's overall estimated IQ. Less than a third of the parents had taken an IQ test or believed they measured IQ very well. Those who were more likely to be better educated, had taken an IQ test, and believed intelligence was inherited were more likely to award themselves higher overall IQ scores. Results are compared with the British studies in the same area.     

Sustained attention and visual processing speed in children and adolescents with bipolar disorder and other psychiatric disorders

To investigate the cognitive functioning of children and adolescents with bipolar illness, 112 child and adolescent psychiatric inpatients and day-hospital patients at a state psychiatric hospital were administered the Wechsler Intelligence Scale for Children-III (WISC-III) as part of an admission psychological assessment. There were 22 patients with Bipolar Disorder and 90 with other psychiatric disorders; all were between 8 and 17 years of age. The patients with Bipolar Disorder had a mean age of 14 yr., a mean Verbal IQ of 78, a mean Performance IQ of 76, and a mean Full Scale IQ of 75. When their WISC-III scores were compared with those who had Schizophrenia Spectrum disorders (Schizophrenia and Schizoaffective Disorder), Psychosis Not Otherwise Specified, Attention Deficit Hyperactivity Disorder, and Conduct Disorder and Oppositional Defiant Disorder, there were no significant between-group mean differences for Verbal IQ, but patients with Bipolar Disorder had a significantly lower mean Performance IQ than those with ADHD and those with Conduct Disorder and Oppositional Defiant Disorder. Contrary to the expectation that the patients with Bipolar Disorder might have better sustained attention (higher Digit Span scores) than those with Schizophrenia Spectrum disorders and worse visual processing speed (lower Coding scores) than the other diagnostic groups, the bipolar patients' Digit Span and Coding scores did not differ significantly from those of the other groups. The patients with Psychosis, Not Otherwise Specified had significantly lower mean Performance IQ, Full Scale IQ, and Coding than the ADHD and the Conduct Disorder and Oppositional Disorder groups.     

Visual imagery can impede reasoning

Although it is natural to suppose that visual mental imagery is important in human deductive reasoning, the evidence is equivocal. This article argues that reasoning studies have not distinguished between ease of visualization and ease of constructing spatial models. Rating studies show that these factors can be separated. Their results yielded four sorts of relations: (1) visuospatial relations that are easy to envisage visually and spatially, (2) visual relations that are easy to envisage visually but hard to envisage spatially, (3) spatial relations that are hard to envisage visually but easy to envisage spatially, and (4) control relations that are hard to envisage both visually and spatially. Three experiments showed that visual relations slow down the process of reasoning in comparison with control relations, whereas visuospatial and spatial relations yield inferences comparable with those of control relations. We conclude that irrelevant visual detail can be a nuisance in reasoning and can impede the process.     

Why do High IQ Societies Differ in Intellectual Achievement? The Role of Schizophrenia and Left-Handedness in Per Capita Scientific Publications and Nobel Prizes

Previous research has attempted to understand why countries with relatively favorable conditions and high estimated average IQs (such as Finland and Japan) have a relatively low per capita number of scientific Nobel prizes. In the present study, we examine whether there is a relationship between national schizophrenia and left-handedness prevalence, on the one hand, and per capita scientific and literary achievement, on the other hand, in countries with IQ estimates of at least 90. We found that per capita science and literature Nobel prizes and scientific publications are strongly negatively associated with schizophrenia and strongly positively correlated with left-handedness. There also was a very pronounced negative correlation between schizophrenia rate and left-handedness rate. These results suggest that genius can be regarded as a combination of very high IQ, aspects of high-functioning autism (specifically low empathy) plus relatively low impulse control, consistent with observations of intellectually outstanding individuals, and the fact that schizophrenia appears to constitute the opposite pole of these aspects of autism spectrum. We posit differences in androgen levels as a possible underlying explanation for these findings.     

Use of the Peabody Picture Vocabulary Test with the educationally handicapped

Despite widespread use of the Peabody Picture Vocabulary Test (PPVT) as a measure of intelligence for educationally handicapped students, few studies have related PPVT scores of such students to their scores on the Wechsler Intelligence Scale for Children (WISC). Using 100 public school students consecutively referred for learning difficulties, their mean PPVT IQ (97.75) was found to be consistently and significantly higher than WISC Full Scale IQ (89.65), Verbal IQ (88.68), and Performance IQ (92.73). Correlations between the PPVT IQ and the WISC Full Scale, Verbal, and Performance IQs were .70, .69, and .54, respectively. A tabular summary of previous studies comparing PPVT and WISC IQs is included.     

The Flynn effect and U.S. policies: the impact of rising IQ scores on American society via mental retardation diagnoses

Over the last century, IQ scores have been steadily rising, a phenomenon dubbed the Flynn effect. Because of the Flynn effect, IQ tests are periodically renormed, making them harder. Given that eligibility for mental retardation (MR) services relies heavily on IQ scores, renormed tests could have a significant impact on MR placements. In longitudinal IQ records from 9 sites around the country, students in the borderline and mild MR range lost an average of 5.6 points when retested on a renormed test and were more likely to be classified MR compared with peers retested on the same test. The magnitude of the effect is large and affects national policies on education, social security, the death penalty, and the military. This paper reports the perceptions of professionals as they relate to IQ score fluctuations in normal, borderline, and/or MR populations.     

National IQs predict educational attainment in math,reading and science across 56 nations

The results of the 2006 PISA (Program for International Student Assessment) study of reading comprehension, mathematical ability, and science understanding administered to 15 year olds in 56 countries [OECD (2007). PISA 2006: Science Competencies for Tomorrow's World. Paris: OECD.] are examined to assess the predictive validity of the national IQs presented by Lynn and Vanhanen [Lynn, R., & Vanhanen, T. (2002). IQ and the wealth of nations. Westport, CT: Praeger., Lynn, R., & Vanhanen, T. (2006). IQ and global inequality. Augusta, GA: Washington Summit Books.], and to assess the contributions of national differences in IQ and educational variables to national differences in educational attainment. It was found that national scores in reading comprehension, mathematical ability, and science understanding are correlated with Lynn & Vanhanen (L & V) national IQs at 0.84; corrected for attenuation, 0.935. This establishes the high validity of Lynn & Vanhanen national IQs. The contribution of national differences in IQ and education variables to national differences in educational attainment obtained in the 2006 PISA 56 nation study showed that the predictive validity of IQ alone was 0.84, and that national IQs together with one economic and two education variables had the validity 0.90 in predicting PISA 2006 results.     

Penser autrement les difficultés scolaires : les apports du Rorschach en système intégré

This study examines school under-achievement from the perspective of clinical psychology. We compare 2 groups of children in the 3^rd grade (mean age 9) based on their results on a national test of French language and Mathematics. We present the Rorschach results of 7 high performers compared to 7 low performers, all of whom have IQ scores (K. ABC) that are in the average range (90 - 109). The Rorschach data (Comprehensive System) demonstrate no differences between these groups of children concerning affective functioning and stress tolerance. However, the quantitative and qualitative results are notably different concerning attitudes relative to complex situations, in the area of critical self-perception and conflict-resolution strategies.     

Personality and place

This paper examines the distribution of national personality dimensions in geographical space. The relationship between geographical location and aggregate personality in a wide range of nations is quantified using spatial autocorrelation, and it is found that the personalities of nations that are geographical neighbours are more similar than those that are far apart. The five factors of both the Revised NEO Personality Inventory (NEO‐PI‐R) and the Big Five Inventory (BFI), all show a significant degree of spatial organization. The personality factors most strongly associated with geographical location are NEO‐PI‐R extraversion and BFI conscientiousness; both vary with position around the globe about as much as the physical climate. These findings support previous research suggesting associations between aggregate personality and geography, and imply that the sources of variation in national personality are themselves geographically organized.     

IQ and alcohol consumption : International data

There is evidence at the individual level that alcohol consumption and IQ are positively related: individuals with higher IQ scores tend to consume relatively more alcohol than those with lower IQs. This paper empirically tests whether this relationship holds at the national level. Using national IQ measures and data on per capita alcohol consumption, we test whether higher-IQ countries on average also have higher levels of per capita beer and wine consumption. Based on regression analysis for a sample of 99 countries, the data do not reject the hypothesis that, other factors held constant, higher IQ predicts higher levels of per capita alcohol consumption at the national level.     

Intelligence and finance

This paper explore the effect of intelligence on financial development using data from 180 nations, over the period 2000–2012. The results provide strong support for the claim that intelligence is positively associated with the supply of finance to economy. This paper establishes that, moving from country with the mean IQ score (84.1) to the highest national IQ score (107.1) is associated with 3.6 fold increase in the size of banking sector. The positive effect of intelligence remains intact when we control for other antecedents of financial development.     

Factor structure of perceptual-motor attributes in normal children: a cross-validation

The scores on 22 items of the Purdue Perceptual-motor Survey, administered to 567 normal school children of mean IQ 103 and mean age of 116 mo., were subjected to R-factor analysis by the method of principal factoring with orthogonal varimax rotation. The analysis led to the definition of 10 factors: J, ocular control; K, dynamic balance; L, visual-motor fluency; M, chalkboard; N, unilateral-bilateral coordination; O, upper-lower body differentiation; P, form perception; Q, developmental maturation; R, sex; and S, spatial body perception. The results provide cross-validation for previous studies on the perceptual-motor attributes of normal school children.     

Normal Versus Noncentral Chi-square Asymptotics of Misspecified Models

In this article, we present a Bayesian spatial factor analysis model. We extend previous work on confirmatory factor analysis by including geographically distributed latent variables and accounting for heterogeneity and spatial autocorrelation. The simulation study shows excellent recovery of the model parameters and demonstrates the consequences of ignoring spatial dependence. Specifically, we find inefficiency in the estimates of the factor score means and bias and inefficiency in the estimates of the corresponding covariance matrix. We apply the model to Schwartz value priority data obtained from 5 European countries. We show that the Schwartz motivational types of values, such as Conformity, Tradition, Benevolence, and Hedonism, possess high spatial autocorrelation. We identify several spatial patterns—specifically, Conformity and Hedonism have a country-specific structure, Tradition has a North–South gradient that cuts across national borders, and Benevolence has South–North cross-national gradient. Finally, we show that conventional factor analysis may lead to a loss of valuable insights compared with the proposed approach.     

National estimates of IQ and suicide and homicide rates

Nations with high estimated mean IQ scores had higher suicide rates and lower homicide rates after control for gross domestic product was introduced, significantly in 1970 but not in 1980.