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.     

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.     

Cross-national social ecology of intelligence and suicide prevalence: integration, refinement, and update of studies

This study integrates, refines, and updates previous findings pertaining to positive ecologic (population-level) associations between intelligence and suicide prevalence across nations by using corrected and revised national IQ estimates and, further, a quality-of-human-conditions index, both recently published by Lynn and Vanhanen. Across a global 85-nation sample of sex-specific total suicide rates and a Eurasian 48-nation sample of sex-specific elderly suicide rates, these were positively associated with updated national IQ estimates. The associations were stronger for the general population than for elderly persons, independent of the quality of human conditions, and notedly stronger in exponential fitting of suicide rates with national IQ than in linear fitting, thereby indicating that shifts or differences in national IQ correspond to proportional, not absolute, changes in suicide rates. Implications of these findings and the question of generalizability of such associations to the individual level are discussed.     

IQ and the wealth of states

In IQ and the Wealth of Nations (2002), Lynn and Vanhanen estimate the mean IQs of 185 nations and demonstrate that national IQs strongly correlate with the macroeconomic performance of the nations, explaining about half of the variance in GDP per capita. I seek to replicate Lynn and Vanhanen's results across states within the United States. I first estimate “state IQs” from the SAT data, and show that the state IQs correlate moderately with the economic performance of the states, explaining about a quarter of the variance in GSP (gross state product) per capita.     

A comparative study of intellectual abilities of Japanese and American children on the Columbia Mental Maturity Scale (CMMS)

Lynn has published a series of papers on cross-cultural comparison of IQs. In three of his papers, Lynn indicated that the Japanese performed higher on IQ tests, and analyzed this from a socio-ecological point of view. This paper presents a comparison of intellectual abilities of Japanese and American children on the Columbia Mental Maturity Scale (CMMS).     

Reversing the speed–IQ correlation: Intra-individual variability and attentional control in the inspection time paradigm

Elementary cognitive tasks (ECTs) are simple tasks involving basic cognitive processes for which speed of performance typically correlates with IQ. Inspection time (IT) has the strongest IQ correlations and is considered critical evidence for neural speed underlying individual differences in intelligence. However, results from Bors et al. [Bors, D.A., Stokes, T.L., Forrin, B. & Hodder, S.L., (1999). Inspection Time and Intelligence: Practice, strategies, and attention. Intelligence, 27, 111–129.] suggest task consistency may underlie this shared variance. One possibility is that performance consistency reflects attentional mechanisms, as previous research has shown relationships between attentional control and cognitive performance. In study 1, participants were administered the Raven's Advanced Progressive Matrices and performed an alternative version of the IT task to measure individual trial-by-trial consistency expressed as the standard deviation of IT (ITSD). The alternative procedure yielded IT–IQ correlations similar to those obtained in previous studies and ITSD accounted for the IT–IQ variance. A second experiment tested whether ITSD measures attentional control, as participants simultaneously performed the IT task and an attention-demanding verbalization task. Under these conditions, high IQ participants performed worse on IT. These results suggest IT performance may reflect individual differences in attentional control and that this variable may account for the variance shared between IT and IQ.     

State preferences for the ACT versus SAT complicates inferences about SAT-derived state IQ estimates: A comment on Kanazawa (2006)

Kanazawa [Kanazawa, S. (2006). IQ and the wealth of states. Intelligence, 34, 593–600.] offered estimates of state IQ derived from SAT data. The purpose of this commentary is to argue that state preferences for the use of the ACT versus the SAT create biased estimates of SAT-derived state IQ for states where the ACT is more frequently used than the SAT. This error can be reduced by using both ACT and SAT data to estimate state IQ. An IQ estimate based on a ACT-SAT composite and a NAEP-derived state IQ estimate were compared as predictors of three wealth variables. Both IQ estimates cause one to conclude that states with higher mean IQ have larger gross state product per capita, higher median incomes, and a lower percentage of their population in poverty.     

Self-estimates of intelligence: a study in two African countries

Black and White South Africans (n = 181) and Nigerians (n = 135) completed a questionnaire concerning the estimations of their own and their relatives' (father, mother, sister, brother) multiple intelligences as well as beliefs about the IQ concept. In contrast to previous results (A. Furnham, 2001), there were few gender differences in self-estimates. In a comparison of Black and White South Africans, it was clear the Whites gave higher estimates for self, parents, and brothers. However, overall IQ estimates for self and all relatives hovered around the mean of 100. When Black South Africans and Nigerians were compared, there were both gender and nationality differences on the self-estimates with men giving higher self-estimates than women and Nigerians higher self-estimates than South Africans. There were also gender and nationality differences in the answers to questions about IQ. The authors discuss possible reasons for the relatively few gender differences in this study compared with other studies as well as possible reasons for the cross-cultural difference.     

Exponential fitting of suicide rate and national intelligence estimates

Positive ecological (group-level) associations of Lynn and Vanhanen's 2002 national intelligence (IQ) estimates with the suicide rates of men and women across 85 countries and with the suicide rates of the male, female, and total elderly population across 48 Eurasian countries reported recently is extended by the finding that this ecological association was notedly better accounted for by exponential fitting than by linear fitting. This evidence implies that the effect of a shift in the national IQ on the suicide rate is proportional, not absolute. As a rule of thumb, a 5-point shift in national IQ roughly corresponds to a 50% change in the national suicide rate.     

Brain mechanisms and intelligence. Psychometric g and executive function

Sternberg [Sternberg, R.J. (1985). Beyond IQ: a triarchic theory of human intelligence. New York: Cambridge Univ. Press.] has proposed that the general intelligence, or the g factor, obtained when batteries of mental tests are factor analyzed, is a reflection of the fact that executive functions (EF) are common to all cognitive tests. Three lines of evidence that fail to support Sternberg's formulation are presented. First, in animal problem solving studies, there is only a modest degree of overlap between brain structures that are critical for g, and brain structures that have been identified as the rodent EF system. Second, children with attention deficit-hyperactivity disorder (ADHD), characterized by EF dysfunction, do not have IQ scores that are lower, on average, than children in the test standardization populations. Third, human frontal lobe patients often have clear EF deficits, but IQ (a next-best estimate of g) may be preserved. These findings cast serious doubt on the plausibility of Sternberg's formulation. Clarifying the distinction between psychometric g and EF can be important for understanding the differences between practical and psychometric intelligence.     

Mitochondrial DNA marker EST00083 is not associated with high vs. average IQ in a German sample

In a recent report in this journal (Plomin & Petrill, 1997), a mitochondrial DNA marker (EST00083) yielded significant associations with high vs. low IQ in two population-based samples of children in the U.S. The present study tested this allelic association for German adults with high vs. average IQ scores. The high IQ adults (N=47) were members of Mensa, an organization whose membership criterion is an IQ score above 130. Their EST00083 allelic frequencies were compared to the allelic frequencies for a control group of adults (N=77) whose IQ scores were less than 110 as estimated from short-term memory and speed-of information-processing tests. Although the differences between the two studies are considerable, the present results do not provide support for the hypothesis that EST00083 is associated with high IQ.     

Common and specific dimensions of self-reported anxiety and depression: the BDI-II versus the BDI-IA

The Beck Depression Inventory-II (BDI-II) [Beck, A. T., Steer, R. A. & Brown, G. K. (1996). Manual for Beck Depression Inventory-II. San Antonio, TX: Psychological Corporation.] and Anxiety Inventory (BAI) [Beck, A. T. & Steer, R. A. (1993a). Manual for the Beck Anxiety Inventory. San Antonio, TX: Psychological Corporation.] were administered to 840 outpatients who were diagnosed with various types of psychiatric disorders to determine whether the general symptom compositions and relative amounts of variance of the common and specific dimensions of self-reported anxiety and depression for these instruments would be comparable to those that had been found by Steer et al. [Steer, R. A., Clark, D. A., Beck, A. T. & Ranieri, W. F. (1995). Common and specific dimensions of self-reported anxiety and depression: A replication. Journal of Abnormal Psychology, 104, 542–545.] with the BAI and amended Beck Depression Inventory (BDI-IA) [Beck, A. T. & Steer, R. A. (1993b). Manual for the Beck Depression Inventory. San Antonio, TX: Psychological Corporation.]. A Schmid–Leiman transformation was used with the iterated-principal-factor pattern matrix of the BAI and the BDI-II loadings and indicated that the overall symptom compositions and relative amounts of variance that were explained by the one common and two specific anxiety and depression dimensions were comparable to those previously found with the BDI-IA.     

Hypnosis,hypnotic suggestibility,memory, and involvement in films

Our research extends studies that have examined the relation between hypnotic suggestibility and experiential involvement and the role of an hypnotic induction in enhancing experiential involvement (e.g., absorption) in engaging tasks. Researchers have reported increased involvement in reading (Baum & Lynn, 1981) and music-listening (Snodgrass & Lynn, 1989) tasks during hypnosis. We predicted a similar effect for film viewing: greater experiential involvement in an emotional (The Champ) versus a non-emotional (Scenes of Toronto) film. We tested 121 participants who completed measures of absorption and trait dissociation and the Harvard Group Scale of Hypnotic Susceptibility and then viewed the two films after either an hypnotic induction or a non-hypnotic task (i.e., anagrams). Experiential involvement varied as a function of hypnotic suggestibility and film clip. Highly suggestible participants reported more state depersonalization than less suggestible participants, and depersonalization was associated with negative affect; however, we observed no significant correlation between hypnotic suggestibility and trait dissociation. Although hypnosis had no effect on memory commission or omission errors, contrary to the hypothesis that hypnosis facilitates absorption in emotionally engaging tasks, the emotional film was associated with more commission and omission errors compared with the non-emotional film.     

IQ differences between the north and south of Italy: A reply to Beraldo and Cornoldi,Belacchi, Giofre,Martini, and Tressoldi

Beraldo (2010) and Cornoldi, Belacchi, Giofre, Martini, and Tressoldi (2010) (CBGMT) have eight criticisms of my paper (Lynn, 2010) claiming that the large north–south differences in per capita income in Italy are attributable to differences in the average levels of intelligence in the populations. CBGMT give results for seven data sets for IQs in the north and south of Italy. All of these show that IQs are higher than in the north than in the south, although the differences are not as great as those I calculated. Other criticisms to the effect that the PISA tests are not measures of intelligence are refuted. The results of two further studies are given that confirm that IQs in the north of Italy are approximately 10 IQ points higher than in south.     

Book Reviews

Book reviewed in this article: Books, Young People, and Reading Guidance . by Geneva Hanna Pilgrim and Mariana K. McAllister. New York: Harper & Row Publishers Publishers wishing to have their books considered for review in this column should send two copies of each book to the Managing Editor, Personnel and Guidance Journal, 1607 New Hampshire Avenue, N.W., Washington, D.C. 20009. Counseling the Disadvantaged edited by William E. Amos and Jean Dresden Grambs. Englewood Cliffs New Jersey: Prentice-Hall, 1968. Scranton, Pennsylvania: International Textbook Company N. Y.: Oceana Publications Blaisdell Publishing Company New York: Social Science Press Antipoverty Work and Training Efforts: Goals and Reality by Sar A. Levitan. Ann Arbor, Michigan: Institute of Labor and Industrial Relations and National Manpower Policy Task Force     

Values in action scale and the Big 5: An empirical indication of structure

Within this study we used self-report measures completed by 123 undergraduate students from an Australian university to investigate the validity of Peterson and Seligman’s [Peterson, C., & Seligman, M. E. P (2004). Character strengths and virtues. New York: Oxford.] classification system of 24 character strengths and six virtues. We also looked at how the 24 character strengths relate to the Five Factor Model of personality and to a measure of social desirability. Using a second order factor analysis of the 24 character strengths, we found that these 24 character strengths did not produce a factor structure consistent with the six higher order virtues as proposed by Peterson and Seligman [Peterson, C., & Seligman, M. E. P (2004). Character strengths and virtues. New York: Oxford.]. Instead, the 24 character strengths were well represented by both a one and four factor solution. Patterns of significant relationships between each of the 24 character strengths, the one and four factor solutions and the Five Factor Model of personality were found. The results have implications for [Peterson, C., & Seligman, M. E. P (2004). Character strengths and virtues. New York: Oxford.] classification.     

Attention deficit disorder in reading-disabled twins: Evidence for a genetic etiology

In order to assess the genetic etiology of attention deficit hyperactivity disorder (ADHD), the basic regression model for the analysis of selected twin data (DeFries & Fulker, 1985, 1988) was fitted to questionnaire data (DICA: Diagnostic Interview for Children and Adolescents; Herjanic, Campbell, & Reich, 1982) for 37 identical and 37 fraternal twin pairs tested in the Colorado Reading Project. Results of this analysis suggest that ADHD is highly heritable. Moreover, adjusting DICA scores for either IQ or reading performance differences did not substantially change parameter estimates. In future analyses of larger data sets, distinguishing between possible subtypes of attentional problems (e.g., ADD with or without hyperactivity) may facilitate tests of more searching etiological questions.This work was supported in part by program project and center grants from NICHD (HD-11681 and HD-27802) to J. C. DeFries. This report was prepared while J. Gillis was supported by NIMH training grant MH-16880, and J. Gilger was supported by a Fellowship in Developmental Psychobiology through the University of Colorado (MH-15442). B. Pennington was also supported by NIMH grants MH-38820 and MH-45916. The invaluable contributions of staff members and families who participated in the Colorado Reading Project are gratefully acknowledged. We also acknowledge the expert editorial assistance of the late Rebecca G. Miles.     

The structural relationships among generalized anxiety, obsessions-compulsions, and depression at the syndrome and sub-syndrome level

This study explored anxiety's relationship to depression by assessing a group of 592 undergraduate psychology students at Washington State University. Multiple measures of generalized anxiety (GA), obsessions–compulsions (O–C), and depression were used to conduct several confirmatory factor analyses (CFAs). A three-factor model of GA, O–C, and depression was found superior in fit to a one-factor “negative-affect” model, a two-factor model of anxiety and depression, and a second-order three-factor model. Further CFAs divided GA, O–C, and depression into six independent symptom category factors utilizing instrument subscales (e.g., worry, somatic anxiety, obsessions, compulsions, cognitive depression, and somatic depression). The fit for this model was superior to three alternative measurement models. The correlations among the six symptom category constructs revealed differential patterns among the cognitive and somatic symptoms.     

Capturing ruminative exploration: Extending the four-dimensional model of identity formation in late adolescence

Identity exploration has been associated with openness and curiosity but also with anxiety and depression. To explain these mixed findings, the four-dimensional identity formation model [Luyckx, K., Goossens, L., Soenens, B., & Beyers, W. (2006b). Unpacking commitment and exploration: Validation of an integrative model of adolescent identity formation. Journal of Adolescence, 29, 361–378.] was extended using data from two late adolescent samples (total N = 703). A fifth dimension, labeled ruminative (or maladaptive) exploration, was added as a complement to two forms of reflective (or adaptive) exploration already included in the model (i.e., exploration in breadth and exploration in depth). Results indicated that ruminative exploration was positively related to distress and to self-rumination. The two forms of reflective exploration, by contrast, were unrelated to well-being and positively to self-reflection. Ruminative and reflective exploration also helped to distinguish between two types of less adaptive identities (i.e., Ruminative Moratorium and Diffused Diffusion) in a six-cluster solution that also contained adaptive types of identity. Implications for current research on identity formation are discussed.