High IQ Group Research Articles

A Longitudinal Study of Exceptional Giftedness and Creativity

This article summarizes a longitudinal study of exceptionally gifted boys, with particular emphasis on ,findings involving their creative potential. The longitudinal investigation began 2 decades ago with 2 exceptionally gifted samples. These samples represented equivalent levels of ability but different areas or domains of talent. One was exceptionally gifted in math and science, the other a high-IQ group (mean IQ = 155). Data were collected from the boys and their parents. The present article summarizes group differences in expectations of independence, California Psychological Inventory (CPI; Gough, 1975) scales, and divergent thinking (DT) test scores. Relations among predictors are also discussed, as are relations with indexes of creative potential. In addition to group differences, notable findings include the strong relation between mothers' expectations for their sons' independence and the DT of the sons and the high flexibility scores of the exceptionally gifted samples on the CPI.

HLA-A and CTGB33 polymorphisms and variation in IQ scores

This study attempted to replicate findings of Plomin et al. ( Plomin and Neiderhiser, 1991). DNA markers associated with high vs low IQ: The IQ quantitative trait loci (QTL) project, Behav. Genet., 24, 107–118) in which significant differences in allelic frequency at a locus in the HLA class I region and the triplet repeat, CTGB33 were found between low and high IQ subjects. The two IQ groups for our study were taken from a sample of elderly people whose IQ was assessed using a measure of intelligence that is highly resistant to the effects of ageing and dementia. The high IQ group had an average IQ of 125 while the lower group's average IQ was 95. No difference was found in the allelic frequencies for any of the CTGB33 alleles or the HLA-A alleles. As there were a number of differences between this study and that of Plomin's group, this can only be viewed as a limited attempt at replication.

Above-Average Intelligence and Neuropsychological Test Score Performance

Recent studies regarding the effects of above average intelligence and neuropsychological performance have been mixed with Dodrill (1977) suggesting that above-average performances on neuropsychological test scores should not be expected when intellectual abilities are above average and Tremont, Hoffman, Scott and Adams (in press) clearly suggesting better neuropsychological skills in the higher IQ group. This paper described a reanalysis of a previously presented Canadian data-set assembled by Pauker (1980) of three hundred and sixty-three persons (152 males, 211 females) who were administered the core tests of the Halstead-Reitan Neuropsychological Test Battery (HRNTB) and the Wechsler Adult Intelligence Scale (WAIS). The results were that subjects with higher intelligence had better neuropsychological test score performances except for the Finger Tapping with the dominant hand test.

Mitochondrial DNA and IQ in Europe

Recently a mitochondrial DNA polymorphism (EST00083) was found at significantly different frequencies in high IQ and low IQ groups in two independent studies. We have used mitochondrial sequences from a range of populations to show that this polymorphism occurred more than once in human history. Furthermore, the polymorphism is particularly common in Europe where it is predominantly associated with a single mitochondrial line (lineage) that appears to date back to the expansion of anatomically modern humans into Europe about 35,000 years ago. Examination of the genetic diversity within this mitochondrial lineage, together with the known migration and settlement of Europeans into the USA, suggests that the observed IQ associated polymorphism found in Cleveland Ohio is likely to be restricted to only one form (sub-group) of this mitochondrial lineage.

Discriminating Factors for Low or High IQ of Children in Care

Two groups of deprived children with contrasting IQs at a preschool age were compared: a low IQ group with IQs between 60 and 80 (LG, n = 49) and a high IQ group with IQs above 106 (HG, n = 42).The objective of the study was to identify discriminating major factors for cognitive development in a population of neglected children in care. They had been selected in a cohort of children who were adopted after the age of 4. A sub‐sample was been studied longitudinally: 14 LG children and 11 HG children with two IQ assessments. Results have shown that forty per cent of these 91 children had emotional disorders and behavioural problems. No statistically significant differences were observed for environment and placement variables between LG and HG. Five variables differentiated the two groups: birth rank, maternal mental retardation, pregnancy and delivery complications, severe prematurity and/or low birth weight, and the number of hospitalisations. They explained 18.5% of the IQ variance at the preschool age. In the sub‐sample of 25 children, an interaction between these two subgroups and IQ level was found (p< 0.001): IQs have increased in the HG subgroup but have remained stable in the LG subgroup. The first cognitive assessment was correlated with IQ at the preschool age. Maternal antecedents and birth risk factors are associated with IQ but the effects of severe neonatal factors on IQ are significantly decreasing with time. Childcare professionals need precise information during the infancy period on risk factors, health problems and maltreatment to organise intervention programs that might prevent subsequent adverse outcome. Further research should investigate the effects of risk factors on the cognitive and behavioural development of these children during adolescence after a total environmental change.

Looking down on human intelligence.

Ian J. Deary's new book is about the biology of individual differences in intelligence. He views psychometrics - the measurement and statistical study of psychological traits, such as intelligence - as being between social variables (such as school attainment, income, accident rates, etc.) and the biology of the brain, with each field building on a base of knowledge from the lower levels. From psychometrics one can look upwards at applications of psychological tests, or one can look downwards onto the biological factors that affect intelligence. Looking down is what this book does. The basic approach is historical, with most modern research described in the last chapters. I would suggest reading the first chapter and then jumping to the later chapters that describe the more modern research. Some of the early writings are mainly of historical interest. These merely serve to demonstrate that the same questions and hypothesizes have been of interest for centuries. The introductory chapter deals with a number of topics that will be familiar to the specialist in intelligence. One is the existence of a general factor. When mental tests are given to the same subjects, the subjects' performances on the different tests are positively correlated. The person who does well on one test generally does well on other tests, and the poor performer on one test is likely to be a poor performer on other tests. This is not what would be expected if solving different types of problems were a learned skill with those better at solving a particular type of problem being better because they had had more practice. Since time spent practicing solving one type of problem is time not spent at practicing on other types of problems, one who was well practiced at one type of problem would tend to be less practiced at another type of problem. In this case, there would be an inverse correlation between performances on different type of problems. However, a positive correlation is observed. This simple observation suggests that individual differences in practice or in study time do not explain individual differences in performance. A brief discussion is given of the many social variables intelligence helps predict such as school performance, income, social status etc. Particularly striking is the data from Hunter and Hunter (1984) on the validity of common hiring criteria. Best at predicting job performance were mental ability composites (.53). This was even better than job tryouts and far exceeded such measures as education (.10), academic achievement (.11), or interviews (.14). Naturally, some of the evidence for the importance of intelligence comes from The Bell Curve (Herrnstein & Murray 1994), which documents the large number of socially important variables that are influenced by intelligence. (A summary of the findings are available in Miller 1995) The introductory chapter also summarizes the evidence on the heritability of intelligence. The traditional methods of behavioral genetics using twins and adoptees show that there is substantial genetic influence on intelligence, which appear to account for most of the variability between people in intelligence. After the introductory discussion, genes are not discussed again until the next to last chapter, which deals with the latest developments in biological research. This chapter (written with coauthors Carl and MacLullich) discusses the quantitative trait loci project. This is an effort to identify specific genes that affect intelligence (or at least are markers for these genes). The basic methodology here is to look for genetic markers that are shared by individuals of high intelligence. To minimize the number of subjects studied the latest research has focused on very high intelligence (gifted with an IQ averaging 136) children, which are compared with normal children. So far evidence has been found that a variation in the insulin-like growth factor-2 receptor (IGF2R) gene is more common in the high IQ groups than in the normal IQ groups and that the effect is unlikely to be due merely to chance. …

The factor structure of the WISC-III for unclassified, learning disabled, and high-IQ groups : Poulson, K. M., & Scardapane, J. R.

The factor structure of the WISC-III for unclassified, learning disabled, and high-IQ groups : Poulson, K. M., & Scardapane, J. R.

The factor structure of the WISC-III for unclassified, learning disabled, and high-IQ groups

The factor structure of the WISC-III for unclassified, learning disabled, and high-IQ groups

Failure to replicate a QTL association between a DNA marker identified by EST00083 and IQ

In a paper published in this journal, a possible QTL association was reported between general cognitive ability and a marker, identified by an expressed sequence tag, EST00083 (Skuder et al., 1995). In two small samples, the frequency of the common allele of this DNA marker, which was shown to be in the threonine transfer RNA gene in mitochondrial DNA, was significantly greater in a high-IQ group than in a low-IQ group. As part of the ongoing IQ QTL Project (Plomin et al., 1995), we have attempted to replicate this QTL association. First, we found that the QTL association remained significant when we compared 51 high- and 51 -average IQ subjects, drawn in part from the samples used in the previous report. However, when we examined the association in new samples of 40 extremely high-IQ subjects and 50 average-IQ subjects, the association did not replicate. This underlies the need for replication in case-control studies of allelic association.

Novelty, Age, and IQ: a Theoretical Look At Human Preference for Novelty

The differences in preferences for novelty among school-aged children who varied in chronological age and IQ were investigated. The results indicated that children in the high-IQ group spent significantly more time responding to novel items than did children in the low-IQ group. Also, children in the high-IQ group devoted a significantly higher percentage of time responding to novel items, relative to total item-inspection time, than did children in the low-IQ group. A significant CA X IQ interaction was found, which indicated that older children with higher IQs exhibited a significantly higher mean percentage of novelty preference than any of the other three groups (i.e., low CA-high IQ, high CA-low IQ, and low CA-low IQ). Correlations between novelty scores and IQ were consistent with those found in the infancy literature. The findings are congruent with the theory that preference for novelty is a continuing phenomenon from infancy through childhood and beyond. We infer that the interest shown by human beings in unfamiliar elements of their environment is one of an unknown number of fundamental building blocks of successful adaptation. We further speculate that the preference-for-novelty phenomenon may offer the underpinnings of a parsimonious solution to the learning paradox.

The effect of IQ level on the degree of cognitive deterioration experienced during acute hypoglycemia in normal humans

Acute hypoglycemia provokes a deterioration in cognitive function both in normal individuals and patients with Type 1 diabetes. A large interindividual variation is observed in the magnitude of the cognitive dysfunction observed during hypoglycemia, the reasons for which are not apparent. This study examines whether IQ level exerts a differential effect on the impairment of cognitive performance induced during acute hypoglycemia. Twenty-four nondiabetic participants were divided into high and average IQ groups according to their results on the Alice Heim 4 test and the National Adult Reading Test. Cognitive function was assessed during hypoglycemia using the following cognitive test battery: Paced Auditory Serial Addition Test (PASAT), Rapid Visual Information Processing (RVIP), Trail-Making B (TMB), Digit Symbol Substitution Test (DSST), and Four-Choice Reaction Time (CRT). In Condition A (the placebo condition), the participants' blood glucose was maintained at 4.5 mmol/1 throughout. On two occasions (Conditions B and C), the blood glucose was stabilized at 4.5 mmol/1 for 30 min, lowered to 2.5 mmol/1 (hypoglycemia) for 60 min, and restored to 4.5 mmol/1 for 30 min. Under each condition, the cognitive test battery was performed immediately after stabilization of blood glucose at 4.5 mmol/1, and the battery was repeated as follows: Condition A—after a further 40 min of euglycemia; Condition B—after 5 min of hypoglycemia; Condition C—after 40 min of hypoglycemia. Multivariate analysis of variance demonstrated a detoriation in cognitive performance as a result of hypoglycemia irrespective of IQ group ( p< .005). Acute hypoglycemia induced a significant deterioration in cognitive function in all tests except TMB ( p< .05). No overall effect of IQ on deterioration in cognitive performance could be ascertained, although univariate analysis of variance revealed an IQ effect on two of the test: The avergae IQ group deteriorated significantly less than the higher IQ group during hypoglycemia in the 4-s PASAT task ( p = .03) and tended to have higher false alarm rates in the RVIP ( p = .06). In conclusion, individuals with a higher IQ do not appear to be protected from tge adverse effects of acute hypoglycemia on cognitive function.

DNA markers associated with high versus low IQ: The IQ quantitative trait loci (QTL) project

General cognitive ability (intelligence, often indexed by IQ scores) is one of the most highly heritable behavioral dimensions. In an attempt to identify some of the many genes (quantitative trait loci; QTL) responsible for the substantial heritability of this quantitative trait, the IQ QTL Project uses an allelic association strategy. Allelic frequencies are compared for the high and low extremes of the IQ dimension using DNA markers in or near genes that are likely to be relevant to neural functioning. Permanent cell lines have been established for low-IQ (mean IQ = 82; N = 18), middle-IQ (mean IQ = 105; N = 21), and high-IQ (mean IQ = 130; N = 24) groups and for a replication sample consisting of even more extreme low-IQ (mean IQ = 59; N = 17) and high-IQ (mean IQ = 142; N = 27) groups. Subjects are Caucasian children tested from 6 to 12 years of age. This first report of the IQ QTL Project presents allelic association results for 46 two-allele markers and for 26 comparisons for 14 multiple-allele markers. Two markers yielded significant (p < .01) allelic frequency differences between the high- and the low-IQ groups in the combined sample-a new HLA marker for a gene unique to the human species and a new brain-expressed triplet repeat marker (CTGB33). The prospects for harnessing the power of molecular genetic techniques to identify QTL for quantitative dimensions of human behavior are discussed.

The nature of intelligence in adults with Down syndrome: IQ distribution and sex differences

Normative data on intelligence in adults with Down syndrome was collected on 93 males and 80 females, aged 16 years and above, who had been given the Suzuki-Binet Intelligence Scale. Both the male and female groups showed bimodal curves in the distributions of IQs. Only for the low IQ groups, the distributions were defined by binomial distributions. The mean ages of starting to walk for the low IQ groups were six months or more later than those for the high IQ groups. However, no significant differences were observed in birthweights, terms of pregnancy, and ages between the two groups. In addition, significant sex differences were found in mean IQs, females scored higher in both the two groups.

Estimating WAIS-R FSIQ from the national adult reading test-revised in normal subjects

Abstract Examined the accuracy of the North American revision of the National Adult Reading Test (NART-R; Blair & Spreen, 1989) in predicting current WAIS-R FSIQ scores in a sample of 302 healthy job applicants. Also wished to establish adult norms for the NART-R according to age, education, and level of intelligence. Finally, also compared the accuracy of the NART-R in predicting WAIS-R FSIQ scores with that of the Reading Subtest of the Wide Range Achievement Test-Revised. Using the prediction equations developed by Blair and Spreen, estimated and obtained mean WAIS-R FSIQs were found to be nearly identical for the group as a whole, with r = .46 (p < 001). However, WAIS-R FSIQ was overestimated by NART-R performance among lower IQ groups, and underestimated among higher IQ groups. The WRAT-R Reading Score correlation with WAIS-R FSIQ was r = .45 (p < .001); the Reading Score also underestimated among higher IQ groups. Using the NART-R, 95% of the subjects had less than 15-point estimated-obtained IQ dif...

The Stability of Cognitive and Behavioral Parameters in Autism: A Twelve-Year Prospective Study

Sixty-two autistic patients enrolled in a prospective study an average of 12 years ago. Current retesting results are now available on 53 of the original 62 patients (85.5%). Results indicate that 36 (67.9%) achieved scores within their original IQ group. Twelve (22.6%) moved up IQ groups and five (9.4%) moved down. Of particular clinical importance is the observation that Vineland Adaptive Behavior Scores were consistently lower than cognitive scores, and maladaptive behaviors occurred with equal frequency in the high, medium, and low IQ groups. The implications of this new data for understanding the natural history of autism, educational and vocational planning, and future research are discussed.

Labour Status of the General US Population and a High IQ Population

The labourforce status of members of American Mensa (a high IQ group) is examined. Compared with a general US sample, the Mensans′ labour‐force participation rate was found to be higher, while the percentage not in the labourforce was lower. Multinomial logit estimation indicates that demographic variables have greater influence on the odds of individuals being in the various labourforce categories for the general US sample than for Mensans. Differences in labourforce patterns for Mensans versus the US sample are due more to differences in characteristics than to underlying behavioural differences.

The social and nonsocial behaviors of precocious preschoolers during free play

From observing 26 precocious preschoolers during free play, it was determined that they engaged in high frequencies of associative and dramatic play. The girls engaged in more cooperative and less solitary play than the boys. The older children participated in more solitary, parallel, and less cooperative and less dramatic play than their younger peers. The higher IQ group (median IQ = 160+) undertook less constructive and more dramatic play than the lower IQ group (median IQ = 137).

Correlations of mental tests with each other and with cognitive variables are highest for low IQ groups

Two studies showed an inverse relationship between ability level and correlations among IQ measures. Low IQ subjects showed much higher correlations than high IQ subjects. Intercorrelations of IQ subtests, correlations of cognitive ability measures with each other, and correlations of IQ with measures of cognitive abilities all displayed the same effect. In the first study, data from two experiments in which subjects took a battery of basic cognitive tasks and a standard IQ test were analyzed. Measures from the basic tasks correlated more highly in the low IQ group than in the high IQ group. In the second study, data from the WAIS-R and WISC-R standardization samples were divided into five ability groups. Average correlations among subtests were computed for each ability group. For both the WAIS-R and WISC-R, average subtest correlations were highest in the low ability group. Correlations declined systematically with increasing IQ. In both studies, correlations were found to be two times higher in low IQ groups than in high IQ groups.

Intellectual deterioration and personality decompensation in schizophrenia.

The Army General Classification Test (AGCT) and the MMPI were administered to schizophrenic inpatients (N = 50) with initially high (mean standard score = 115) and low (77) intelligence at two timepoints separated by an average of 14 years. The Arithmetic scores of the more intelligent group declined significantly with time, but significant changes did not appear on the Vocabulary or Spatial Aptitude scores of that group. No significant mean changes appeared in the low-IQ sample. The high-IQ group's Arithmetic section deterioration resulted from an increased error rate, not a drop in speed. No changes beyond those attributable to chance appeared on the MMPI scales. The results suggest that an intellectual decline limited to certain skills and to a subset of subjects occurs in schizophrenia and that the deterioration is not attributable to personality decompensation as defined by the MMPI. Because these findings appear to contrast with most previous research in this area, they should be considered tentative until confirmed by independent studies.

Intelligence Scores of Gifted Students on the WISC-R

In order to examine the hypothesis that children identified as "gifted" may have different patterns of scores on the WISC-R than children not identified as "gifted", the present study examined the WISC-R scores of three groups of children: those scoring in the average range, those with high IQ's, and those identified as "gifted." Factor analysis conducted on a sample of children identified as "gifted" yielded a four-factor solution accounting for approximately 65% of the total variance: Perceptual Organization, Verbal Comprehension, Acquisition of Knowledge, and Spatial Memory. Analyses of groups of children with average and above average intelligence scores revealed two- and three-factor solutions for the average children, but a pattern similar to the gifted child for the high IQ group. Results suggest that gifted children process information in a qualitatively different manner from average children.