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Internal consistency reliabilities of the WISC-IV subtest and index scores were estimated for a sample of 76 primary school students from a small Midwestern community. Means for age and Full Scale IQ were 8.2 yr. (SD = 2.3) and 110.5 (SD = 11.7), respectively. Internal consistency reliabilities were compared with those for the WISC-IV standardization sample of 200. The range of reliabilities for the subtests was from .76 for Picture Concepts to .94 for Arithmetic and from .92 for Perceptual Reasoning Index to .96 for Verbal Comprehension Index and Full Scale IQ. The Full Scale IQ internal consistency reliability is comparable to that of the standardization sample. However, in all but one instance the reliabilities were greater than those of the normative sample.

Science requires postformal capabilities to compare competing explanations and conceptualize how to coordinate or integrate them. With conflicts thus reconciled, science advances. The Model of Hierarchical Complexity facilitates the coordination of current arguments about intelligence. A cross-species measurement theory of comparative cognition is proposed. It has potential to overcome the lack of a general measurement theory for the science of comparative cognition, and the lack of domain-general mechanisms for evolutionary psychologists. The hierarchical complexity of concepts and debates as well as the new theory are scored, and demonstrate the postformal hierarchical complexity of the proposed theory. KEYWORDS: Comparative cognition, domains, evolutionary psychology, hierarchical complexity, g, intelligence, IQ, measurement theory.

Since the emergence of twin studies in the 1920s, time and again the question of possible twin-singleton differences in intelligence has been posed. This study addressed the issue through a meta-analysis of published studies on this theme. Twins on the average seem to have lower IQs than singletons. The best estimate for this group difference is 4.2 IQ points (less than one-third of a standard deviation), with a great divide between study outcomes of less vs more recent birth cohorts (5.1 vs 0.5 IQ points, respectively). The evidence is based on studies from six countries (including population-based ones of entire birth cohorts), a massive database (comparisons of more than 30,000 twins with nearly 1.6 million singletons), a variety of intelligence tests, and birth cohorts spanning most of the 20th century, but, for the most part, on an age range limited to children and adolescents. The effect shows considerable between-study heterogeneity but appears robust (fail-safe N calculations), not due to influential individual studies (sensitivity analysis) or publication bias, was present since the very first published studies (cumulative meta-analysis), and appears generalizable across sex, zygosity, and other intelligence domains beyond the verbal. There are insufficient data as to whether the effect persists over the lifespan, exists as well within families, or has ceased in recent birth cohorts of highly developed countries (Denmark and The Netherlands). Likely causes of the effect appear to be prenatal and perinatal factors (reduced fetal growth and shorter gestation for twins).

Researchers have examined inductive reasoning to identify different cognitive processes when participants deal with inductive problems. This article presents a prescriptive theory of inductive reasoning that identifies cognitive processing using a procedural strategy for making comparisons. It is hypothesized that training in the use of the procedural inductive reasoning strategy will improve cognitive functioning in terms of(a) increased fluid intelligence performance and (b) better academic learning of classroom subject matter. The review and meta-analysis summarizes the results of 74 training experiments with nearly 3,600 children. Both hypotheses are confirmed. Further, two moderating effects were observed: Training effects on intelligence test performance increased over time, and positive problem-solving transfer to academic learning is greater than transfer to intelligence test performance. The results cannot be explained by placebo or test-coaching effects. It is concluded that the proposed strategy is theoretically and educationally promising and that children of a broad age range and intellectual capacity benefit with such training. KEYWORDS: cognitive training, inductive reasoning, problem-solving transfer.

The absolute as well as differential stability in general intelligence 'g' and in verbal and arithmetic abilities are determined longitudinally for 4000+ adult male veterans. The ordinary t-test was used in order to estimate the absolute stability and the absolute scores from the recurrent tests were correlated to determine the differential stability.

Psychometric measures can be used to identify if cognitive dimensions are independent of general intelligence and these dimensions can also be studied for any neuroanatomical correlates. Two such dimensions, rotation-verbal and focus-diffusion are investigated.

The diffusion model can predict that IQ scores correlate better with longer reaction time than shorter reaction time. The model explains both the reaction times and accuracy.

Lynn and Vanhanen present a data that shows strong relationship between IQ scores and Gross Domestic Product per capita. It helps to find the relationship between the cognitive competence of a national population and nation's economic prosperity.

IQ test scores have risen steadily across the industrialized world ever since such tests were first widely administered, a phenomenon known as the Flynn effect. Although the effect was documented more than 2 decades ago, there is currently no generally agreed-on explanation for it. The author argues that the phenomenon heterosis represents the most likely cause. Heterosis, often referred to as hybrid vigor, is a genetic effect that results from matings between members of genetically distinct subpopulations, such as has been occurring in human populations through the breakup of small, relatively isolated communities owing to urbanization and greater population mobility. In Part 1 of the article, empirical findings are listed that are consistent with a heterosis hypothesis but render other hypotheses either implausible or very difficult to test. In Part 2, a formal model of the process of heterosis is presented. The goal of the modeling is to develop a quantitatively rigorous method for estimating the potential contribution of heterosis in the Flynn effect, as well as trends observed in other heritable traits and conditions. Keywords: heterosis, Flynn effect, IQ, secular trend

An estimate of state IQ is derived, its strengths and limitations are considered and the extent to which state IQ predicts state outcome variables is estimated. A research agenda is provided for improving estimates of state IQ, identifying factors that cause differences in state IQ and delineating the role of IQ in predicting important variables.

Elementary students in programs for gifted and highly gifted students were tested using the Stanford-Binet Intelligence Scales, Fifth Edition (SB5). Students' scores on the SB5 were significantly lower than their scores on the Wechsler Intelligence Scale for Children--Third Edition (WISC-III). In addition, rank order was not well preserved between the SB5, WISC-III scores, and determination of giftedness. While the cause of these findings is unclear, caution should be used when utilizing the SB5 for determinations of gifted status., The year 2003 ushered in revisions of the two intelligence scales most commonly used in determinations of giftedness--the Stanford-Binet (Roid, 2003) and the Wechsler Scales (Wechsler, 2003). Both scales reflect [...]

Royer's method of componential analysis was applied to understand what exactly is measured by the widely used substitution tests. The visual search ability of the participants on basis of their symbol-digit performance was observed and the results of the study illustrated the usefulness of creating a multiform substitution test for evaluating individual differences.

Reductions in latent inhibition (LI), the capacity to screen from conscious awareness stimuli previously experienced as irrelevant, have been generally associated with the tendency towards psychosis. However, 'failure' to screen out previously irrelevant stimuli might also hypothetically contribute to original thinking, particularly in combination with high IQ. Meta-analysis of two studies, conducted on youthful high-IQ samples, demonstrated that high lifetime creative achievers had significantly lower LI scores than low creative achievers ([r.sub.effect size] = .31, p = .0003, one-tailed). Eminent creative achievers (participants under 21 years who reported unusually high scores in a single domain of creative achievement) were 7 times more likely to have low rather than high LI scores, [chi square] (1, N = 25) = 10.69, [phi] = .47, p = .003.

The article critiques the use of regression-based estimations of premorbid intelligence to calculate the extent of damage to the intellect after a traumatic brain injury. Specific precautions are given for using regression analysis depending on whether the intelligence quotient is above or below 100.

The authors defend their recommendation of regression estimates of premorbid intelligence quotient, demonstrating that the method is both unbiased and produces the maximum-likelihood IQ estimate.

Correlations between single-item self-reports of intelligence and IQ scores are rather low (.20-.25) in college samples. The literature suggested that self-reports could be improved by three strategies: (1) aggregation, (2) item weighting, and (3) use of indirect, rather than direct, questions. To evaluate these strategies, we compared the validity of aggregated and unaggregated versions of direct measures with four indirect measures (Gough's Intellectual efficiency scale, Hogan's Intellect composite scale, Sternberg's Behavior Check List, and Trapnell's Smart scale). All measures were administered to two large samples of undergraduates (Ns = 310, 326), who also took an IQ test. Although results showed some success for both direct and indirect measures, the failure of their validities to exceed .30 impugns their utility as IQ proxies in competitive college samples. The content of the most valid items referred to global mental abilities or reading involvement. Aggregation benefited indirect more than direct measures, but prototype-weighting contributed little.

The relationship between brain size and intelligence was examined in a large sample of healthy normal volunteers (N = 90). In addition to confirmation of the small but significant relationship [...]

Four hundred kindergarten children in regular education and 31 kindergarten children identified as gifted were presented a cognitive battery consisting of nine different tasks. Five measures representing the three open-ended tasks were associated with both a significant group difference and the presence of high performing outliers from the regular education sample. When frequency distributions for the two groups were computed based on a total score summed over the five measures, seven of the eight regular education students with the highest score, the upper 2%, were either Black/NonHispanic or White/Hispanic. The upper 2% of the regular education sample performed at a level above 81% of the gifted sample. The data suggest that using a child's performance on a cognitive battery may prove to be effective for identifying gifted minority children who have not previously been identified as having superior cognitive abilities.

The Chinese version of the WAIS-R was factor analyzed for a sample of 130 Chinese adults in Hong Kong who had low intellectual abilities. All subtests except the Vocabulary subtest were included for analyses. Results supported a three-factor solution composed of Verbal Comprehension, Perceptual Organization, and Memory/Freedom from Distractibility Factors, as well as a two-factor solution of classic Verbal-Perceptual dichotomy. Comparison of present two- and three-factor structure with individuals having low or normal IQ in Mainland China and North America revealed satisfactory congruence coefficients. However, our general factor accounted for only a small portion of common and total variance (28.5% and 35.3% respectively). Error variances of our subtests were large when compared to normative samples of Mainland China and US. Results were discussed in terms of clinical interpretation of the WAIS-R subtests, danger of using short-forms to assess IQ and need for normative studies of WAIS-R in Chinese-speaking countries.

The WAIS-R (Wechsler, 1981) and elderly WAIS-R standardization samples (Ryan, Paolo, & Brungardt, 1990) were combined to evaluate the utility of the Barona demographic regression equations (Barona, Reynolds, & Chastain, 1984) to estimate premorbid intelligence. The equations underestimated ability for persons with IQs less than 80 and overestimated ability of subjects with IQs greater than 119. The equations also overestimated the IQs of 247 persons with confirmed brain dysfunction. Because this overestimation occurred for impaired persons with IQs less than 90, it is difficult to determine whether the difference reflects true intellectual deterioration or statistical artifact. Abnormal cut-off scores at the 10% and 5% levels are provided to allow clinicians to detect abnormal discrepancies between the estimated and obtained IQs.

An analysis of the link between the Wechsler Adult Intelligence Scale and Wilson predictor of premorbid intelligence scores of 27 depressed and 34 nondepressed psychiatric patients confirmed the major difference between the scores. Verbal and Performance IQs effects of depression on the depressed patients' capacity to perform at premorbid levels is marginal.

Infant predictors of adult IQ were assessed with same-sex infant twins (114 pairs) and their parents. The midtwin-midparent design permits the rapid assessment of infant measures to predict later behavior, because the midparent score serves as a proxy for the infant's potential score at maturity At 5, 7, and 9 months, Ss were observed on the Fagan Test of Infant Intelligence, hand preference, vocalizations, selected Bayley Scales of Infant Development items, and a modified Bayley Infant Behavior Record. At 8 months, Ss received the Visual Expectation Paradigm and an auditory discrimination task. Their parents received the Wechsler Adult Intelligence Scale - Revised. Some infant measures, indicative of information processing, language ability, and temperament, predicted midparent IQ. This study extended and partially replicated findings from a previous midtwin - midparent cohort (L. E DiLaila et al., 1990).

Relations between personality and intelligence were investigated in the context of the distinction between intelligence as typical engagement and intelligence as maximal engagement. The traditional approach to investigating the association between intelligence as maximal performance and personality was reviewed, and suggestions were made, including the suggestion that intelligence as typical engagement results in clearer understanding of personality-intelligence relations. Thirteen personality/interest constructs hypothesized to surround a core construct of typical intellectual engagement and related to typical intellectual performance were operationalized. Relations found were modest, yet several personality scales differentially related to fluid and crystallized classes of intelligence. Relations between the personality constructs surrounding typical intellectual engagement and the broad personality domain are investigated.

The aim of this study was to identify factors that might affect reaction-time (RT) testing and interpretation. Simple reaction time and choice reaction time were measured in a cohort of 893 white young men. Age, body size, color vision., and intelligence (IQ) were analyzed as subject-related factors. Effects of time of day of test and different examiners were analyzed in relation to testing facilities. All factors were statistically correlated to RTs; however, the relationships between age and RTs and between height and RTs were noticeably weak and apparently insignificant in practice. A defect in color vision was notably associated with slow choice RT and with mistakes on the test. As the choice was coded by color in the choice RT test, the result was expected. Low IQs were significantly related with slow RTs. Slow RTs have been correlated with low-grade IQs in previous studies also. Lower grades and greater variation in RTs were recorded just before meals or if testing was done outside the daily testing schedule. The examiner supervising the RT testing significantly affected the results. It was concluded that the introduction for tests should be given impersonally using a tape recorder or comparable equipment.

239 British and 118 Chinese Hong Kong nine-year-old children, each representative for intelligence of Britain and Hong Kong, were tested on the Standard Progressive Matrices and on reaction times. The reaction time apparatus measured simple and complex reaction times proper (i.e., decision times), movement times, and variabilities. The results showed that all the reaction time measures were associated with intelligence and that Hong Kong children had a higher mean IQ and faster reaction times than British children. This suggests that the difference in mean IQ between Hong Kong and British children has a neurological basis. However, the British children showed faster movement times and lower variabilities, contrary to expectation. This suggests independent neurological processes may underlie reaction times, movement times, and variabilities.

The hypothesis that reaction times are positively associated with intelligence was tested on 479 9-yr.-old Chinese Hong Kong children. Intelligence was measured by the Standard Progressive Matrices, and 12 reaction time parameters were obtained to give measures of movement times, reaction times proper (decision times), differentiated into simple and complex reaction times, and their variabilities. Factor analysis of the reaction time tasks indicated the presence of a general reaction time factor and three component factors identifiable as movement times, reaction times proper, and variabilities. All three components showed statistically significant association with intelligence of approximately equal magnitudes.

Recent infant research in attention and information processing has shown that individual differences in infancy can predict later intelligence quotient (IQ). To assess the best predictors of IQ later on, healthy same-sex infant twins (208 pairs) and their parents were studied. Parents were given an IQ test and a battery of other tests assessing cognitive ability, and twins were given tests of visual expectations. Twins' IQs were then retested at one, two and three years of age. All analyses were repeated separately for boys and girls. Girls scored significantly higher on IQ scores at ages one, two and three years. This finding is attributed to early gender differences in temperament. Average scores of individual twin-sets (midtwin scores) for all the early study measures were correlated with midtwin IQ scores assessed at ages one, two and three years. Overall, results contribute to the body of evidence pointing to stability in intellectual development from infancy on. The best predictors of later IQ, and of midparent IQ scores were found to be: (1) the visual expectations test administered at eight months; (2) Fagan's Test of Infant Intelligence, which measures infant novelty preference and recognition memory; and, (3) testing at nine-months with the Bayley's Infant Behavior Record, which assesses social orientation, cooperativeness, fearfulness, and level of responsiveness. (Consumer Summary produced by Reliance Medical Information, Inc.)

Assessments pose numerous dilemmas in the assessment of an individual. Two primary concerns with standardized assessments are which instrument should be used for the assessment and what assessment specialist should do he assessing. The Wechsler Adult Intelligence Scale-REvised is the most utilized instrument for measuring an adult's IQ. A neuropsychological evaluation is examined using the Wechsler Adult Intelligence Scale-Revised. The purpose of neuropsychological testing is disclosed along with the areas of the brain which are being assessed., Assessments are ongoing dilemmas in every facet of mankind. Doctors assess their patients both physically, mentally, and emotionally. Bosses assess their employers on job performance, attendance, and employee relations. Educators [...]

Short form of Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) having eight subtest was developed for the psychiatric population which expands on its predecessors in ways to reduce administration time and increase breadth of information obtained.

There is little evidence showing the relationship between the Scholastic Assessment Test (SAT) and g (general intelligence). This research established the relationship between SAT and g, as well as the appropriateness of the SAT as a measure of g, and examined the SAT as a premorbid measure of intelligence. In Study 1, we used the National Longitudinal Survey of Youth 1979. Measures of g were extracted from the Armed Services Vocational Aptitude Battery and correlated with SAT scores of 917 participants. The resulting correlation was .82 (.86 corrected for nonlinearity). Study 2 investigated the correlation between revised and recentered SAT scores and scores on the Raven's Advanced Progressive Matrices among 104 undergraduates. The resulting correlation was .483 (.72 corrected for restricted range). These studies indicate that the SAT is mainly a test of g. We provide equations for converting SAT scores to estimated IQs; such conversion could be useful for estimating premorbid IQ or conducting individual difference research with college students.

Two-component theories of intellectual development over the life span postulate that fluid abilities develop earlier during child development and decline earlier during aging than crystallized abilities do, and that fluid abilities support or constrain the acquisition and expression of crystallized abilities. Thus, maturation and senescence compress the structure of intelligence by imposing age-specific constraints upon its constituent processes. Hence, the couplings among different intellectual abilities and cognitive processes are expected to be strong in childhood and old age. Findings from a population-based study of 291 individuals aged 6 to 89 years support these predictions. Furthermore, processing robustness, a frequently overlooked aspect of processing, predicted fluid intelligence beyond processing speed in old age but not in childhood, suggesting that the causes of more compressed functional organization of intelligence differ between maturation and senescence. Research on developmental changes in functional brain circuitry may profit from explicitly recognizing transformations in the organization of intellectual abilities and their underlying cognitive processes across the life span.

Since the time of Plato, we have been fascinated by the notion of intelligence and how to measure it. In 1904, Spearman proposed the existence of a general factor of [...]