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Differences in cognitive ability, per capita income, infant mortality, fertility and latitude across the states of India
Abstract
Regional differences in cognitive ability are presented for 33 states and union territories of India. Ability was positively correlated with GDP per capita, literacy and life expectancy and negatively correlated with infant and child mortality, fertility and the percentage of Muslims. Ability was higher in the south than in the north and in states with a coast line than with those that were landlocked.
... Bagley (1925), Teasdale, Owen, andSørensen (1988), Holsinger (2007), and Roivainen (2012) argued that IQ differences, in the US, Denmark, Vietnam, and Germany, respectively, were caused by educational differences. Similarly, Lynn and Yadav (2015) proposed, as one of five possible explanations for the correlation between the IQs and socioeconomic outcomes of Indian states and territories, that the IQ differences between Indian states were due to educational differences resulting from regional differences in prosperity. Finally, León and Avilés (2016) argued that IQ differences in Peru were caused by behavioral differences that were in turn caused by differences in contemporaneous UV radiation exposure. ...
... Eppig, Fincher, and Thornhill (2011) put forward a parasite-stress hypothesis, according to which IQ differences are an effect of a developmental trade-off between IQ and immune function. Lynn (1979), Lynn (1980), Dutton and Lynn (2014), Lynn and Yadav (2015), Almeida, Lemos, andLynn (2011), Lynn (1981), and Lynn, Sakar, and Cheng (2015) argued for and/or investigated the effect of selective migration within particular countries (respectively, Britain, France, Finland, India, Portugal, Spain, and Turkey). Kirkegaard and Fuerst (2017) (Argentina), Kirkegaard (2016a, 2016b) (Brazil, Chile, Colombia, Mexico, and US), Lynn and Cheng (2013) and Lynn, Cheng, and Wang (2016) Pesta and Poznanski (2014), Templer and Rushton (2011) (US) proposed and/or investigated differences related to ethnicity and ancestry. ...
... Kirkegaard and Fuerst (2017) (Argentina), Kirkegaard (2016a, 2016b) (Brazil, Chile, Colombia, Mexico, and US), Lynn and Cheng (2013) and Lynn, Cheng, and Wang (2016) Pesta and Poznanski (2014), Templer and Rushton (2011) (US) proposed and/or investigated differences related to ethnicity and ancestry. For India, Lynn and Yadav (2015) also suggested differences resulting from different rates of consanguineous marriage related to religious practices (Muslim versus non-Muslim). Lastly, de Baca and Figueredo (2014) suggested both socioeconomic and ecological factors, the latter of which, according to these authors, could have acted over evolutionary time. ...
Differences in intelligence have previously been found to be related to a wide range of inter-individual and international social outcomes. There is evidence indicating that intelligence differences are also related to different regional outcomes within nations. A quantitative and narrative review is provided for twenty-two countries (number of regions in parentheses): Argentina (24 to 437), Brazil (27 to 31), British Isles (12 to 392), to 79), Spain (15 to 48), Switzerland (47), Turkey (12), the USA (30 to 3100), and Vietnam (61). Between regions, intelligence is significantly associated with a wide range of economic, social, and demographic phenomena, including income (r unweighted = .56), educational attainment (r unweighted = .59), health (r unweighted = .49), general socioeconomic status (r unweighted = .55), and negatively with fertility (r unweighted = −.51) and crime (r unweighted = −.20). Proposed causal models for these differences are noted. It is concluded that regional differences in intelligence within nations warrant further focus; methodological concerns that need to be addressed in future research are detailed.
... The most commonly reported of these have been positive associations with per capita income, educational attainment, life expectancy and stature, and negative associations with infant mortality and fertility. These associations have been reported for the regions of the British Isles (Lynn, 1979), France (Lynn, 1980), the United States (McDaniel, 2006;Shatz, 2009), Italy (Lynn, 2010;Piffer & Lynn, 2014), Portugal (Almeida, Lemos, & Lynn, 2011), Spain (Lynn, 2012), China (Lynn & Cheng, 2013), Japan (Kura, 2013), Finland (Dutton & Lynn, 2014), India (Lynn & Yadav, 2015) Turkey (Lynn, Sakar, & Cheng, 2015) and European Russia in the late nineteenth century (Grigoriev, Lapteva, & Lynn, in press). ...
... Second, the negative correlation of intelligence with infant mortality (r = − 0.43, p b 0.01) confirms the negative negative correlation (r = −0.28) for European Russia in the late nineteenth century reported by Grigoriev et al. (in press) and is consistent with the negative correlations across the regions of the British Isles (r = − 0.78), France (r = − 0.30), Italy (r = − 0.80), the American states (r = − 0.54), Finland (r = − 0.79) and India (r = − 0.39) (Dutton & Lynn, 2014;Lynn, 1979Lynn, , 1980Lynn, , 2010Lynn & Yadav, 2015;Reeve & Basalik, 2011). At the individual level an association between infant mortality and the low IQ of mothers has been reported by Savage (1946). ...
... and the regions of India (r = −0.25) (Lynn & Yadav, 2015) and with studies in many countries showing dysgenic fertility during the twentieth and twenty-first centuries (Lynn, 2011a;Woodley & Figueredo, 2013). ...
Data are reported for educational attainments as a measure of intelligence, a number of socio-economic variables, and latitude and longitude for 79 provinces of the Russian Federation. The average intelligence of the provinces was significantly positively correlated with urbanization (r = 0.43), the percentage of ethnic Russians (r = 0.39), net migration (r = 0.54) and latitude (r = 0.35), such that intelligence was higher in the north, and significantly negatively correlated with infant mortality (r = − 0.43), fertility (r = − 0.39) and longitude (r = − 0.36), such that intelligence was higher in the west.
... The most commonly reported of these have been positive associations with per capita income, educational attainment, life expectancy and stature, and negative associations with infant mortality and fertility. These associations have been reported for the regions of the British Isles (Lynn, 1979), France (Lynn, 1980), the United States (Shatz, 2009), Italy (Lynn, 2010;Piffer & Lynn, 2014), Portugal (Almeida, Lemos, & Lynn, 2011), Spain (Lynn, 2012), China (Lynn & Cheng, 2013), Japan (Kura, 2013), Finland (Dutton & Lynn, 2014), India (Lynn & Yadav, 2015) and Turkey (Lynn, Sakar, & Cheng, 2015). ...
... This is justified on the grounds that a high correlation between literacy rates and intelligence have been reported in a number of studies. For example, a correlation of .861 between literacy rates for Italian regions in 1880 and early twenty-first century IQs has been reported by Lynn (2010); a correlation of .83 between literacy rates for Spanish regions in the early twenty-first century has been reported by Lynn (2010); (Lynn, 2012); and a correlation of 0.56 between literacy rates and IQs for the states and union territories of India in 2011 has been reported by Lynn and Yadav (2015). There is additional support for using literacy in the nineteenth century as a proxy for intelligence in the results of a study by Grigoriev, Lapteva and Ushakov (Григорьев, Лаптева, Ушаков, 2015) showing a correlation of .58 between literacy rates of the peasant populations of the districts (uezds) of the Moscow province in 1883 and the results of the Unified State Exam and State Certification on Russian Language in the districts of the contemporary Moscow oblast. ...
... Negative correlations between regional IQ and fertility have been reported for the states of the United States (Shatz, 2009;Reeve & Basalik, 2011), the regions of Turkey and the regions of India (Lynn & Yadav, 2015). The negative correlations between regional IQs and fertility indicate that fertility was dysgenic in these countries in the early twenty-first century. ...
Regional differences are presented for literacy adopted as a proxy for intelligence, infant mortality, fertility, stature and geographical location for 50 provinces in European Russia in the late nineteenth century. All variables were significantly inter-correlated. Intelligence was significantly higher in the north and west than in the south and east.
... Diversos estudos investigaram as correlações entre as habilidades cognitivas (HC) de populações de diferentes regiões do planeta e os seus respectivos indicadores sociais, ressaltando que maior habilidade cognitiva média dos habitantes de uma localidade geográfica prediz seus respectivos indicadores sociais, como maior Produto Interno Bruto (PIB) per capita, mais anos de escolaridade, elevada expectativa de vida ao nascer e superiores Índices de Democracia e de Desenvolvimento Humano (IDH). Além disso, nessas regiões onde há maior média de HC de seus habitantes, existem menores taxas de mortalidade infantil, de natalidade e de violência, em relação às regiões do globo que possuem uma menor média de HC de seus cidadãos (Almeida et al., 2011;Bakhiet & Lynn, 2015;Lynn, Sakar & Cheng, 2015;Lynn & Yadav, 2015). ...
... As HC possuem correlações negativas e estatisticamente significativas com as TOT, em vários anos diferentes (Tabela 4). Esses resultados estão de acordo com diversos estudos que verificaram que a média das HC dos habitantes de uma localidade prediz seus respectivos indicadores sociais, incluindo diversos tipos de mortes, ou seja, estados ou nações com maiores médias de HC possuem melhores indicadores sociais geralmente (Almeida et al., 2011;Bakhiet & Lynn, 2015;Lynn & Yadav, 2015). Silva (2003) expôs, por meio de estudos epidemiológicos e experimentais, que há diversos comportamentos relacionados fortemente ao aumento dos acidentes de trânsito, com ou sem mortes. ...
Deaths in traffic represent a global and multicausal problem. We verified, through a linear regression model, that cognitive abilities (CA) and population indebtedness (PI) predict, together, 56% of the variation of death rates in the traffic (DT) of the twenty-seven states of Brazil. CA’s are related to a greater control of the attention and, possibly, to a greater compliance with norms for preventing traffic accidents, has a greater impact than PI on DT, since PI associates to only one deficit of people's attention resources. The decrease of PI and the improvement of CA can decrease DT.
... Finland and the contemporary Russian Federation (r=-.43) (Dutton & Lynn, 2014;Grigoriev, Lapteva & Lynn, 2016;Grigoriev, Ushakov et al., 2016;Lynn, 1979Lynn, , 1980Lynn, , 2010Lynn & Yadav, 2015;Reeve & Basalik, 2011). These results at the aggregate level are consistent with the negative association of infant mortality with IQ of mothers reported by Savage (1946). ...
... European Russia in the late nineteenth century (r=-.28), and the contemporary Russian Federation (r=-.39) (Grigoriev, Lapteva & Lynn, 2016;Grigoriev, Ushakov et al., 2016;Lynn, Sakar & Cheng, 2015;Lynn &Yadav, 2015;Shatz, 2009).These results are consistent with studies in many countries showing that dysgenic fertility for intelligence has been near-universal during the twentieth and twenty-first centuries (Lynn, 2011;Woodley & Figueredo, 2013). In Latin America, this has been confirmed through path analysis by León & Avilés (2016), who reported cognitive ability fertility path coefficients ranging between -.25 and -.40 for a set of more than 1000 districts in Peru. ...
In a number of countries, earlier studies have reported significant associations between regional differences in intelligence within countries and economic and social phenomena. Using scores on the Program of International Student Assessment (PISA) tests as indicator of intelligence, we find statistically significant correlations for the 27 states of Brazil between intelligence and nine indicators of socioeconomic development. Spatial analysis indicates that relationships are present both at the level of differences between adjacent states and over long-distance clines. Most of the relationships observed after initial analysis persisted after controlling for spatial autocorrelation. Among the socioeconomic variables, those that describe the standard of living of the less affluent sections of the population tend to correlate most with PISA scores.
... Finland and the contemporary Russian Federation (r=-.43) (Dutton & Lynn, 2014;Grigoriev, Lapteva & Lynn, 2016;Grigoriev, Ushakov et al., 2016;Lynn, 1979Lynn, , 1980Lynn, , 2010Lynn & Yadav, 2015;Reeve & Basalik, 2011). These results at the aggregate level are consistent with the negative association of infant mortality with IQ of mothers reported by Savage (1946). ...
... European Russia in the late nineteenth century (r=-.28), and the contemporary Russian Federation (r=-.39) (Grigoriev, Lapteva & Lynn, 2016;Grigoriev, Ushakov et al., 2016;Lynn, Sakar & Cheng, 2015;Lynn &Yadav, 2015;Shatz, 2009).These results are consistent with studies in many countries showing that dysgenic fertility for intelligence has been near-universal during the twentieth and twenty-first centuries (Lynn, 2011;Woodley & Figueredo, 2013). In Latin America, this has been confirmed through path analysis by León & Avilés (2016), who reported cognitive ability fertility path coefficients ranging between -.25 and -.40 for a set of more than 1000 districts in Peru. ...
In a number of countries, earlier studies have reported significant associations between regional differences in intelligence within countries and economic and social phenomena. Using scores on the Program of International Student Assessment (PISA) tests as indicator of intelligence, we find statistically significant correlations for the 27 states of Brazil between intelligence and nine indicators of socioeconomic development. Spatial analysis indicates that relationships are present both at the level of differences between adjacent states and over long-distance clines. Most of the relationships observed after initial analysis persisted after controlling for spatial autocorrelation. Among the socioeconomic variables, those that describe the standard of living of the less affluent sections of the population tend to correlate most with PISA scores.
... India could be an even better example for declining genotypic intelligence after an early entry into the Neolithic. Cold Winters theory and genetic admixture (Reich et al., 2009) predict a higher IQ in Northern India, but the IQ is higher in Southern India (Lynn & Yadav, 2015). The better explanation is that the Neolithic started in North India 9000-9500 years ago (Dikshit, 2013) and in South India only 4000-5000 years ago (Fuller, Boivin & Korisettar, 2007;Shipton et al., 2012). ...
... Cold Winters theory works best for regions where the Neolithic transition started in the South and spread northward: Near East-Europe (Lynn & Meisenberg, 2010;Lynn & Vanhanen, 2012), Italy (Lynn, 2010), Spain (Lynn, 2012), Russia Grigoriev, Lapteva & Lynn, 2016), Japan (Kura, 2013). For regions where the Neolithic transition started in the North and spread southward, the distribution of IQ does not conform with predictions of Cold Winters Theory: India (Lynn & Yadav, 2015), China (Lynn & Cheng, 2013), South-East Asia (Lynn & Meisenberg, 2010;Lynn & Vanhanen, 2012). ...
When comparing the current IQ maps of Europe and the
Near/Middle East with the maps showing the proportion of DNA
inherited from Neolithic farmers, we notice that IQ is increasingly
lower as Neolithic genetic inheritance is greater. This suggests that
the transition from the Palaeolithic to the Neolithic might have led
to a decline of intelligence, as Robert Klark Graham (1970)
claimed, and that human intelligence had reached its peak with the
Cro-Magnons. Comparing the same IQ maps with the geographic
advance of the Neolithic and of complex post-Neolithic
civilizations, we notice that the average IQ today is lower in regions
that had an earlier entrance into the Neolithic and into complex
civilization, suggesting that genotypic intelligence declined during
or after the Neolithic, as maintained by Elmer Pendell (1977), and
as demonstrated for modern Western civilization by Richard Lynn
(1996) and confirmed recently by molecular evidence
(Beauchamp, 2016; Conley et al., 2016). Studies of ancient DNA
can test this theory of intelligence decline in the near future.
Key Words: Genotypic intelligence; Natural selection; IQ maps;
Neolithic revolution; Civilizations; Polygenic scores; Allele
frequency; DUF1220.
... Test publishers who have translated and adapted IQ tools such as the Wechsler instruments have increased access to assessment in the Indian population, with clinical, societal, and economic benefit. This access has revealed links between IQ scores and important socioecological variables in India such as maternal deprivation, malnourishment, illness, environmental deprivation, stress, water fluoride levels, outdoor pollution, indoor or household air pollution (e.g., cooking or heating by solid biomass fuels such as wood, animal dung, or crop waste), regional differences in GDP per capita, variable literacy rates, differential regional life expectancies, child mortality and fertility rates (Lynn & Yadav, 2015;Kaur, 2012;Ruan-Iu et al, 2020;Brabhukumr et al., 2020;(Sebastian & Sunitha, 2015)). While there are many benefits to increasing access to IQ testing in LMICs such as India, there has been less critical consideration of the processes involved in test adaptations or translations from Western to non-western contexts. ...
Objective
This study critically examined the adaptation and normative processes of the Wechsler Adult Intelligence Scale–Fourth Edition (WAIS-IV)India.
Method
WAIS-IV U.K. Edition Administration and Scoring Manual, WAIS-IVIndia Administration and Scoring Manual, and WAIS-IV Administration and Scoring Manual and Technical and Interpretive Manuals were used to extract test development and adaptation process data. The analyses were descriptive and qualitative.
Results
A review of the manuals showed that the normative sample were fluent English speakers with high education levels, which is not representative of India's multilingual and educational diversity. The study identified minimal cultural and linguistic adaptations in subtests, which raised concern about potential biases in the test adaptation process across cultures. The lack of clarity in item selection, demographic data, sample selection, and psychometric properties raised questions about the test's reliability and validity. Issues related to education, age, gender, and regional distribution are discussed, emphasizing the test's limitations in capturing the diverse characteristics of the heterogeneous Indian population.
Conclusions
WAIS-IV India may not adequately represent India's population. More careful consideration of socioecological and psychometric factors when adapting intelligence (IQ) tests and use of advanced data harmonization methods can provide robust cross-national statistical harmonization in the future along with more ecologically valid local test development efforts. This can allow consideration of social determinants of health and other factors that can inform a more nuanced approach to IQ test development in non-western contexts.
... Aligned with empirical findings (Lu et al., 2022) and Bergmann's rule, the height PGS also has a positive correlation with latitude (r = .72/.82), which parallels the actual height correlations with latitude (r = .77). In contrast, latitude showed no correlation with either educational attainment PGSs or measured IQ averages, reinforcing the absence of an association observed in ancient European genomes (Piffer & Kirkegaard, 2024) or inside India (Lynn & Yadav, 2015). Moreover, the absence of a significant correlation was not obscured by any apparent nonlinear relationships, although the small sample size (n = 28 provinces) limited our ability to detect nonlinear associations. ...
This study assesses the predictive accuracy of polygenic scores (PGS) from a variety of genome-wide association studies (GWAS) in a dataset of 28 Chinese provinces, with a focus on educational attainment (EA) and height. European-derived EA PGSs showed stronger correlations with average IQs of Chinese provinces (r = .52) than did East Asian-derived PGSs (r = .21), likely reflecting larger sample sizes. Both height PGSs derived from mixed ancestry and from European samples were positively correlated with average height (r = .71 and .68). Additionally, both genetic and phenotypic height showed positive correlations with latitude (r = .72 and .77, respectively), corroborating Bergmann’s rule and supporting the observation that northern Chinese tend to be taller. The PGS derived from within-family GWAS of height showed stronger correlation (r = .82) with phenotypic height and latitude than the between-family derived PGS. Whereas IQ PGS was positively correlated to latitude (r = .42), this was not the case for EA PGS. Negative correlations were also observed between schizophrenia PGS and both EA and IQ PGS (r = −.44 and −.50). Results from multiple regression analyses indicated that both genetic factors and environmental conditions (measured by HDI and infant mortality) influenced stature, with genetic factors having a stronger effect (∼ 0.8) compared to environmental conditions (∼ 0.22 to 0.45). Mediation analysis showed that the genetic effects of EA and IQ PGS on IQ are partially mediated through their effects on HDI and infant mortality. Applying Jensen’s method, we found that polygenic scores with a stronger genetic signal of selection exhibited slightly higher predictive accuracy (r = .25−0.27, p < .01). Keywords: Polygenic score, Education, Height, Intelligence, China
... Intelligence differences are also related to different regional outcomes within nations [24]. For example, a study [25] proposed that IQ differences among Indian regions were explained by educational differences arising from regional development inequalities. Since schools' performance may differ from other factors besides location, a simple inspection of data does not make it possible to assess whether there are any fundamental factors behind the considerable differences in school performance. ...
This paper analyses whether schools with better scores in National Exams are in regions NUTs III with greater purchasing power. Accordingly, we analyse the evolution of the ranking of schools considering the purchasing power of the regions where they are located. Using data collected in the media, related to school rankings by region for 2008 and 2014 and in Pordata database for regional purchasing power in 2007 and 2011, we calculate location and specialization measures and perform a regional shift-share analysis. The results show that schools located in regions with very high and high purchasing powers rank first, and both structural and regional changes are positive. A notable exception is the region of Alto Alentejo with a medium purchasing power. In contrast, regions with low purchasing power show negative structural and regional changes. These results indicate that, with an exception, the gap between regions of low and high purchasing powers has been perpetuated.KeywordsEconomic growthEducation performanceHuman capitalRegional convergenceShift-share analysis
... Eine ausgezeichnete Dokumentation der Ergebnisse findet sich inWalker (2011). 12 Informationen über die Bundesländer Indiens finden sich zum Beispiel bei ASER (2019),Dundar et al. (2014),Lynn und Yadav (2015),Walker (2011). ...
Der World Development Report der World Bank 2018 enthält zwei Botschaften, eine gute und eine schlechte. Die gute lautet: Alle Länder dieser Welt haben große Anstrengungen unternommen und die Schulbesuchsquote massiv gesteigert. Von wenigen Ausnahmen abgesehen können heute überall in der Welt fast alle Kinder eine Schule besuchen. Die schlechte Nachricht lautet: Heute können zwar fast alle Kinder eine Schule besuchen, aber Hunderte Millionen lernen so gut wie gar nichts. Diese traurige Tatsache wird von der UNESCO als Global Learning Crisis bezeichnet. Die vorliegende Arbeit gibt einen Überblick über die beiden Aspekte. Neben internationalen Bildungsstudien wie PISA, TIMSS & Co. wird auch die psychometrische Intelligenzforschung berücksichtigt. __________
Stichwörter: Global Learning Crisis, Schule, Schulbesuch, Lernen, Bildung, internationale Bildungsstudien, PISA, Intelligenz, IQ, Millenniumsziele, Agenda 2030, Lernarmut, Corona-Pandemie
... Large differences between the more developed and less developed provinces are the rule rather than the exception, for both cognitive and economic indicators. Uneven cognitive development has been demonstrated, for example, in Turkey (Lynn, Sakar & Cheng, 2015), India (Lynn & Yadav, 2015), China (Lynn, Cheng & Wang, 2016), and Brazil . ...
This study presents the results of a standardized English examination that was administered nationwide to 24,343 grade 8 primary school students in Jordan in 2016. The large majority were from public schools. Not only those from private schools, but also those from UNRWA (UN Relief and Works Agency) schools scored higher than those from public schools. Overall, girls scored higher than boys although boys outscored girls in coeducational public schools. Regional differences were of moderate magnitude and paralleled socioeconomic development, with slightly lower scores in the South than the North and lowest scores in the East. Results are discussed with regard to school quality, regional development, and gender equity in Jordan.
... fertility rate has been established as a determinant of wellbeing of children Acheampong, Ejiofor, Salinas-miranda, Wall, & Yu, 2019). Fertility rate is strongly correlated with maternal mortality at of coeficient 0.7398 indicating when fertility rate goes up maternal mortality will equally go up holding all and mothers health (Lynn & Yadav, 2015) and high fertility rate without the needed investment in health delivery makes west Africa less a safer place for women and children in terms of health delivery (Acheampong et al., 2019). ...
World Health Organization provides reliable information about health performance of countries around the global. In most of their periodical data, sub-Saharan Africa kept performing poorly in relation to most health indicators such as maternal mortality, child mortality, HIV AIDS rate, health financing, vaccination coverage for under 1year child and others.
... The past two decades have seen a quick increase in research on the topic of cognitive training, or the targeted efforts of scientists to improve cognitive ability by way of behavioral interventions. This focus is both warranted and unsurprising given how important cognitive ability is for life success (e.g., Strenze, 2007;Watkins et al., 2007;Lynn & Yadav, 2015), and some of the inspiration for training approaches can be traced to the observation that performing certain tasks seems to be related to improved cognition. For instance, chess players (Burgoyne et al., 2016;Sala et al., 2017) and musicians (Schellenberg, 2011;Swaminathan et al., 2017) have repeatedly been shown to demonstrate greater performance on tests of intelligence than non-playing individuals. ...
Recent meta-analyses and meta-analytic reviews of most common approaches to cognitive training broadly converge on describing a lack of transfer effects past the trained task. This also extends to the more recent attempts at using video games to improve cognitive abilities, bringing into question if they have any true effects on cognitive functioning at all. Despite this, video game training studies are slowly beginning to accumulate and provide evidence of replicable improvements. Our study aimed to train non-video game playing individuals in the real-time strategy video game StarCraft II in order to observe any subsequent changes to perceptual, attentional, and executive functioning. Thirty hours of StarCraft II training resulted in improvements to perceptual and attentional abilities, but not executive functioning. This pattern of results is in line with previous research on the more frequently investigated “action” video games. By splitting the StarCraft II training group into two conditions of “fixed” and “variable” training, we were also able to demonstrate that manipulating the video game environment produces measurable differences in the amount of cognitive improvement. Lastly, by extracting in-game behavior features from recordings of each participant’s gameplay, we were able to show a direct correlation between in-game behavior change and cognitive performance change after training. These findings highlight and support the growing trend of more finely detailed and methodologically rigorous approaches to studying the relationship between video games and cognitive functioning.
... In addition to studies that compared intelligence between countries, the differences in intelligence were studied inside of a nation [8][9][10][11][12]. In this context of comparing different populations' intelligences, the research on this theme and its implications for the social indicators in Brazil's states and the Federal District (FD) of Brasilia are important since the country has an extensive territorial dimension; these states contain areas similar to the areas of several nations. ...
The aim of this study was to investigate the effects of intelligence and income on nutrition in Brazil, by means of large-scale secondary data. The cognitive abilities of students were used as a measure of intelligence. In order to evaluate the nutritional quality of the population, the state hunger and undernutrition index (SHUI) was created. The intelligence explained 34% of the SHUI variation in the country. The development of the population's intelligence influences the decrease in the rates of hunger and undernutrition.
... Cognitive ability declines with proximity to the equator between countries [53,63] and within such countries as Italy [58] , Japan [35] , Peru [44,51] , Russia [28] , Spain [59] , Sudan [3] , the United States [20,45,46,74,86] , and Vietnam (Kirkegaard & Pesta, 2018), although not in Turkey [60] nor India [64] . The exceptions may be accounted for by the greater longitudinal than latitudinal extension of Turkey and the fact that Mus-lims, whose IQ is lower than the IQ of followers of other faiths [57,92] , are more concentrated in the northern regions of India (Basant & Shariff, 2010). ...
Few explanations of geography’s influence on economic and cognitive development have been proposed. This study was purported to test three development models based on absolute latitude (AL) and additionally addressed altitude above sea level and the particular case of the Amazonía in Peru. Information on 1468 Peruvian districts was obtained from Peru’s Ministry of Education and United Nations Development Program’s Human Development Report. The data were best fitted by ad hoc path models which combined AL with altitude and took different forms in the Amazonía and remainder of Peru. AL + altitude explained education + health, and income, through cognitive ability in the Amazonía. In the remainder of Peru, AL – altitude explained income and cognitive ability through education + health, with an additional, weak but significant, direct AL → cognitive ability path. The findings add to evidence suggesting the mediation of UV radiation in the relationship between latitude and development.
... The former includes most of the Southern states where the plantation system, with its large number of black slaves, predominated before the Civil War. Furthermore, residence in proximity to the coasts is indicated to be associated to better health and wellbeing (Wheeler, White, Stahl-Timmins, & Depledge, 2012), higher cognitive ability of infants (Lynn & Yadav, 2015), and better nutritional status of children (Shin, Aliaga-Linares, & Britton, 2017). Also, Mitchell and Popham (2008) and Maas, Verheij, Groenewegen, De Vries, and Spreeuwenberg (2006) indicate that access to good environments may play a part in reducing health inequalities. ...
This study considers whether lung cancer death rates are converging in the United States. Using annual data for the contiguous U.S. states during 1968–2016, the findings indicate the occurrence of β -convergence in lung cancer deaths among various demographic groups. The convergence is more prevalent in the Midwest, non-Black Belt region, and non-coastal states. Given the declining trends in lung cancer incidence and death rates, such a convergence implies an improvement in lung cancer prevention strategies of the states that were not doing quite well in the past. The findings have important policy implications regarding the dissemination of lung cancer prevention strategies across specific groups and regions.
... The country does have multiple ethno-linguistic groups. There are cognitive differences between provinces (Lynn & Yadav, 2015), and therefore between ethnic groups, but these are not evident in the Young Lives study which was limited to the state of Andhra Pradesh. ...
This paper compiles cognitive test results for children in Ethiopia, Andhra Pradesh (India), Peru and Vietnam from multiple rounds of the Young Lives study. In this international project, the same cognitive tests were administered to children of the same age under standardized conditions, allowing comparisons between countries and between social, ethnic, linguistic and religious groups within countries. Comparisons between countries on non-verbal tests show differences that closely resemble those that have been seen in earlier assessments of scholastic achievement and intelligence. Within each of the four countries there are significant differences between social, ethnic, linguistic and in some cases religious groups that are related to socioeconomic conditions. These results have implications for the management of inequalities that have either been present for a long time or that arise in developing countries during the process of modernization.
... Intelligence differences are also related to different regional outcomes within nations (Lynn et al., 2018). For example, Lynn & Yadav (2015) proposed that IQ differences between Indian states were due to educational differences resulting from regional differences in prosperity. ...
... Unfortunately, given the small sample size and the multitude of plausible evolutionary environment candidates, it seems very difficult to determine which are the relevant ones, if any. One possible solution is to use subnational datasets which offer much larger sample sizes (Kirkegaard, 2016b;Lynn & Yadav, 2015;Manrique Millones, Flores-Mendoza, & Millones Rivalles, 2015), but also likely more strongly violate the assumption of no recent population migration. ...
In the United States, cognitive ability, socioeconomic status (SES), and genetic ancestry vary by race/ethnic identification. However, it is not known to what degree genetic ancestry is a useful predictor of outcomes independent of those cultural factors related to race/ethnic identification. Data from the Pediatric Imaging, Neurocognition, and Genetics Study (PING) (N = 1,369 children) were used to examine this issue. In regression models using 4 different codings for SIRE as a covariate, non-trivial incremental relationships were found between genetic ancestry and both cognitive ability and SES. These relationships were reduced somewhat when parental SES was added as a predictor with cognitive ability as the outcome. These associations generally held when subgroups were analyzed separately. Results were congruent with familial models of group differences. Implications for research on race/ethnic differences in the Americas are discussed.
... Literacy rate and per capita income are negatively related to the infant mortality rate [27]. Regional differences in cognitive ability of 33 states and union territories of India is positively correlated with GDP, per capita income, literacy and life expectancy and negatively correlated with infant and child mortality [28]. ...
Children are important properties of a country, for that reason, diminution in infant and child mortality is likely the most important purpose of the Millennium Development Goals. Neonatal survival is a very sensitive indicator of population growth and socioeconomic development. World Health Organization has generated enormous data related to these kinds of research. It has provided definitions, terminologies and technical guidelines in addition to throwing valuable information on fetal and infant death across the countries. Theoretically, these types of research have mainly quantitative though partially qualitative while on the basis of applied perspectives; it could be diagnostic as well as exploratory in nature. Multi-stage random sampling can be appropriate sampling for the study of concerning issues. Structured Interview Schedule will be used for interviewing the women, to provide a complete reproductive history of the births. This information will be used to calculate norms for direct estimates of fetal and infant mortality, according to Barfield & Committee on Fetus and Newborn. The result of these types of studies will identify the root causes of fetal and infant death in the tribal and rural settings of India. It would improve our understanding of the causes of failure of the health services in tribal and rural regions. Besides, it can be of help, to design the new health strategies and programs for the tribal and rural India. On the basis of above all discussion, it is urgent need to conduct such type of research in tribal and rural India.
... Complex cognitive ability (CCA), measured by IQ and/or math, reading, and/or science scores (Rindermann, 2007), increases with proximity to the poles between countries (León & Burga-León, 2015;Lynn & Vanhanen, 2012) and within such countries as Italy (Lynn, 2010), Japan (Kura, 2013), Peru (León & Burga León, 2014), Russia (Grigoriev, Lapteva, & Lynn, 2016), Spain (Lynn, 2012), Sudan (Bakhiet & Lynn, 2015), and the USA (Eppig, Fincher, & Thornhill, 2011;León, 2016;Pesta & Posnanski, 2014;Ryan, Bartels, & Townsend, 2010), although not in Turkey (Lynn, Sakar, & Cheng, 2015) or India (Lynn & Yadav, 2015). While some potential explanations for these observed patterns are controversial, there is a serious public health rationale for exploring the mechanisms underlying variation in cognition as they may entail, inter alia, exposure to preventable disease (Hassall & Sherratt, 2011). ...
Temperature, geo-residential pattern of subpopulations, prevalence of infectious diseases, and UV radiation have been proposed to explain the declining cognitive ability observed with proximity to the equator in the USA. This study tested the cognitive effects of the four variables. The results reveal that the latitudinal decline of cognitive ability is strongly correlated with the UV Index rather than with the other variables among White children. The decline in measured cognitive ability from north to south is absent among African American and Hispanic children, plausibly because the high levels of skin melanin among these ethnic groups, by absorbing and dissipating light, prevent the occurrence of radiation’s cognitive effects among these populations at USA latitudes. The possible physiological mediators (oxidative stress, folate degradation, sexual hormones) suggest diet, family planning, and educational methods as mitigating strategies; however, specific studies measuring the mediating variables are needed to confirm their role and further strengthen UV radiation as an explanatory concept.
... (Lynn, Sakar & Cheng, 2015), the regions of India (r = -.25) (Lynn & Yadav, 2015), for European Russia in the late nineteenth century (r = -.28) (Grigoriev, Lapteva & Lynn, 2016) and for 79 provinces of the Russian Federation using educational attainments as a measure of intelligence (r = -.39) ...
Data are reported for intelligence and fertility in the Russian Federation. There was a statistically significant negative correlation for 29 provinces showing dysgenic fertility for intelligence in contemporary Russia. The negative relationship between test score and number of children was observed at the individual level as well. This relationship is not linear: only third and higher order births are associated with lower intelligence. Dysgenic fertility for intelligence was greater for men than for women, mainly because Raven scores of childless women were slightly lower than those of women with one or two children.
... Many recent studies have examined within-country regional correlates of (general) cognitive ability (also known as (general) intelligence, general mental ability, g),. This has been done for the British Isles (Lynn, 1979;Kirkegaard, 2015g), France (Lynn, 1980), Italy (Lynn, 2010;Kirkegaard, 2015e), Spain (Lynn, 2012), Portugal (Almeida, Lemos, & Lynn, 2011), India (Kirkegaard, 2015d;Lynn & Yadav, 2015), China (Kirkegaard, 2015f;Lynn & Cheng, 2013), Japan (Kura, 2013), the US (Kirkegaard, 2015b;McDaniel, 2006;Templer & Rushton, 2011), Mexico (Kirkegaard, 2015a) and Turkey (Lynn, Sakar, & Cheng, 2015). This paper examines data for Brazil. ...
Sizeable S factors were found across 3 different datasets (from years 1991, 2000 and 2010), which explained 56 to 71% of the variance. Correlations of extracted S factors with cognitive ability were strong ranging from .69 to .81 depending on which year, analysis and dataset is chosen. Method of correlated vectors supported the interpretation that the latent S factor was primarily responsible for the association (r’s .71 to .81).
... This is a pity, because the data allow for a more interesting analysis with the S factor (Kirkegaard, 2014b). Previously (Kirkegaard, 2015), I reanalyzed Lynn and Yadav (2015) and found both general cognitive (G) and general socioeconomic (S) factors (Rindermann, 2007). In this paper I reanalyze data published by Lynn and Cheng (2013) as well as additional data downloaded from the Chinese statistical agency. 2 ...
I analyze the S factor in Chinese states using data obtained from Lynn and Cheng as well as new data obtained from the Chinese statistical agency. I find that S correlates .42 with IQ and .48 with ethnic Han%.
... I reanalyze data published by Lynn and Yadav (2015) for Indian states. I find both G and S factors which correlate at .61. ...
I reanalyze data published by Lynn and Yadav (2015) for Indian states. I find both G and S factors which correlate at .61.
The statistical language R is used thruout the paper and the code is explained. The paper thus is both an analysis as a walkthru of how to conduct this type of study.
... Whatever the name, it is a field that has received renewed attention recently. Richard Lynn and co-authors reported data on Italy (Lynn, 2010a(Lynn, , 2010b(Lynn, , 2012aPiffer & Lynn, 2014; see also papers by critics), Spain (Lynn, 2012b), China (Lynn & Cheng, 2013) and India (Lynn & Yadav, 2015). Two of his older studies cover the British Isles and France (Lynn, 1979(Lynn, , 1980. ...
I reanalyze data reported by Richard Lynn in a 1979 paper concerning IQ and socioeconomic variables in 12 regions of the United Kingdom as well as Ireland. I find a substantial S factor across regions (66% of variance with MinRes extraction). I produce a new best estimate of the G scores of regions. The correlation of this with the S scores is .79. The MCV with reversal correlation is .47.
This study aims to understand some of the main trends in tourist segmentation in the context of fashion tourism, with an emphasis on relationship marketing. The research study brings together a proposed conceptual model to understand some of the main determinants of tourist demand in fashion tourism environments and their behavioral intentions (i.e., satisfaction and loyalty). Fashion tourism is a niche market segment that evolved out of three major sectors: creative tourism, cultural tourism, and shopping tourism. Fashion tourism can be defined as the interaction between Destination Marketing Organizations (DMOs), trade associations, tourism suppliers, and host communities, with people traveling to and visiting a particular place for business or leisure to enjoy, experiment, discover, study, trade, communicate about and consume fashion. The present study represents an important contribution in relation to the management of tourist destinations and the development of the relationship with the consumer. This manuscript is an aid to marketing and management in specific contexts of fashion tourism. The present study has as its main limitation its embryonic stage, not including collection of primary data or development of an empirical study.KeywordsSegmentationFashion tourismTourism marketingRelationship management
The objective of the study was to identify the important Cognitive and Literacy characteristics exhibited by the students perusing UG and PG courses. Further to investigate the relationship between Cognitive and Literacy. For the study, the researcher adopted a descriptive research design, wherein the data was collected from 416 students perusing Schools in the Chennai district. The researcher adopted a simple random sampling technique. Herein the data was collected using a structured questionnaire. From the analysis performed it was understood that an equal proportion of male and female respondents were considered for the study. For the study 217 UG students and 199 students were considered. It can be interpreted that Learning attitude, ReThinking and Information are the important Cognitive characteristics exhibited by the students. Also, it was found that Word reading ability, Spelling and Structuring are the important literary characteristics exhibited by the students. Through the study, it was found that there is a 72.1% positive relationship between Cognitive and literacy. Furthermore, it was identified that the Cognitive of the students influences their literacy.
The objective of the study was to identify the important Cognitive and Literacy characteristics exhibited by the students perusing UG and PG courses. Further to investigate the relationship between Cognitive and Literacy. For the study, the researcher adopted a descriptive research design, wherein the data was collected from 416 students perusing Schools in the Chennai district. The researcher adopted a simple random sampling technique. Herein the data was collected using a structured questionnaire. From the analysis performed it was understood that an equal proportion of male and female respondents were considered for the study. For the study 217 UG students and 199 students were considered. It can be interpreted that Learning attitude, ReThinking and Information are the important Cognitive characteristics exhibited by the students. Also, it was found that Word reading ability, Spelling and Structuring are the important literary characteristics exhibited by the students. Through the study, it was found that there is a 72.1% positive relationship between Cognitive and literacy. Furthermore, it was identified that the Cognitive of the students influences their literacy.
Due to potential theoretical and societal implications, cognitive training has been one of the most influential topics in psychology and neuroscience. The assumption behind cognitive training is that one’s general cognitive ability can be enhanced by practicing cognitive tasks or intellectually demanding activities. The hundreds of studies published so far have provided mixed findings and systematic reviews have reached inconsistent conclusions. To resolve these discrepancies, we carried out several meta-analytic reviews. The results are highly consistent across all the reviewed domains: minimal effect on domain-general cognitive skills. Crucially, the observed between-study variability is accounted for by design quality and statistical artefacts. The cognitive-training program of research has showed no appreciable benefits, and other more plausible practices to enhance cognitive performance should be pursued.
Cross-regional correlations between average IQ and socio-economic development have been reported for many different countries. This paper analyses data on average IQ and a range of socio-economic variables at the local authority level in the UK. Local authorities are administrative bodies in local government; there are over 400 in the UK, and they contain anywhere from tens of thousands to more than a million people. The paper finds that local authority IQ is positively related to indicators of health, socio-economic status and tertiary industrial activity; and is negatively related to indicators of disability, unemployment and single parenthood. A general socio-economic factor is correlated with local authority IQ at r = .56. This correlation increases to r = .65 when correcting for measurement error in the estimates of IQ.
Cross-regional correlations between average IQ and socioeconomic development have been documented in many different countries. This paper presents new IQ estimates for the twelve regions of the UK. These are weakly correlated (
r
=0.24) with the regional IQs assembled by Lynn (1979). Assuming the two sets of estimates are accurate and comparable, this finding suggests that the relative IQs of different UK regions have changed since the 1950s, most likely due to differentials in the magnitude of the Flynn effect, the selectivity of external migration, the selectivity of internal migration or the strength of the relationship between IQ and fertility. The paper provides evidence for the validity of the regional IQs by showing that IQ estimates for UK nations (England, Scotland, Wales and Northern Ireland) derived from the same data are strongly correlated with national PISA scores (
r
=0.99). It finds that regional IQ is positively related to income, longevity and technological accomplishment; and is negatively related to poverty, deprivation and unemployment. A general factor of socioeconomic development is correlated with regional IQ at
r
=0.72.
Data are presented for intelligence in twelve regions in Turkey showing that intelligence is highest in the west and lowest in the east. The west–east intelligence gradient is significantly correlated with regional differences in educational attainment and per capita income and negatively correlated with fertility, infant mortality and the percentage of Kurds.
This article summarizes the practical and theoretical implications of 85 years of research in personnel selection. On the basis of meta-analytic findings, this article presents the validity of 19 selection procedures for predicting job performance and training performance and the validity of paired combinations of general mental ability (GMA) and the 18 other selection procedures. Overall, the 3 combinations with the highest multivariate validity and utility for job performance were GMA plus a work sample test (mean validity of .63), GMA plus an integrity test (mean validity of .65), and GMA plus a structured interview (mean validity of .63). A further advantage of the latter 2 combinations is that they can be used for both entry level selection and selection of experienced employees. The practical utility implications of these summary findings are substantial. The implications of these research findings for the development of theories of job performance are discussed.
This study investigates the dimensions of cultural variation in the modern world as assessed by the World Values Survey. It confirms the previously reported existence of two major dimensions of cultural variation that can be described as modern and "postmodern," respectively. Modern values are characterized by skepticism and critical thinking, with a rejection of religion and traditional authority along with an interest in politics. In multiple regression models, modern values are directly related to the IQ of the population. Postmodern values are characterized by trust, tolerance, and self-realization. In multiple regression models, they are inversely related to corruption. Subjective well-being is positively related to postmodern values and negatively to modern values. Modern values are interpreted as the emancipation of reason from the constraints of traditional custom and religion, and postmodern values as the emancipation of pleasure-seeking and social emotions from the constraints of dysfunctional social systems. The historical context and the roles of these value orientations in the evolution of contemporary societies are discussed.
Background:
Cognitive ability tests are widely assumed to measure maximal intellectual performance and predictive associations between intelligence quotient (IQ) scores and later mental health problems. Very few epidemiologic studies have been done to demonstrate the relationship between familial inbreeding and modest cognitive impairments in children.
Objective:
We aimed to estimate the effect of inbreeding on children's cognitive behavior in comparison with non-inbred children.
Methodology:
A cohort of 408 children (6 to 15 years of age) was selected from inbred and non-inbred families of five Muslim populations of Jammu region. The Wechsler Intelligence Scales for Children (WISC) was used to measure the verbal IQ (VIQ), performance IQ (PIQ) and full scale IQ (FSIQ). Family pedigrees were drawn to access the family history and children's inbred status in terms of coefficient of inbreeding (F).
Results:
We found significant decline in child cognitive abilities due to inbreeding and high frequency of mental retardation among offspring from inbred families. The mean differences (95% C.I.) were reported for the VIQ, being -22.00 (-24.82, -19.17), PIQ -26.92 (-29.96, -23.87) and FSIQ -24.47 (-27.35,-21.59) for inbred as compared to non-inbred children (p<0.001) [corrected].The higher risk of being mentally retarded was found to be more obvious among inbred categories corresponding to the degree of inbreeding and the same accounts least for non-inbred children (p<0.0001). We observed an increase in the difference in mean values for VIQ, PIQ and FSIQ with the increase of inbreeding coefficient and these were found to be statistically significant (p<0.05). The regression analysis showed a fitness decline (depression) for VIQ (R2 = 0.436), PIQ (R2 = 0.468) and FSIQ (R2 = 0.464) with increasing inbreeding coefficients (p<0.01).
Conclusions:
Our comprehensive assessment provides the evidence for inbreeding depression on cognitive abilities among children.
The north–south difference in Italy in PISA 2006 scores in reading comprehension, mathematical and science abilities of 15-year-olds has been attributed by Lynn (2010a) to a difference of approximately 10 IQ points in intelligence and by critics to differences in educational resources. New evidence for differences between north and south Italy in the PISA 2012 Creative Problem Solving test as a measure of fluid intelligence shows a 9.2 IQ point between the north–west and the south and confirms Lynn's theory. New data are presented for genetic differences between the populations of north and south Italy.
Background
India is home to many ethnically and linguistically diverse populations. It is hypothesized that history of invasions by people from Persia and Central Asia, who are referred as Aryans in Hindu Holy Scriptures, had a defining role in shaping the Indian population canvas. A shift in spoken languages from Dravidian languages to Indo-European languages around 1500 B.C. is central to the Aryan Invasion Theory. Here we investigate the genetic differences between two sub-populations of India consisting of: (1) The Indo-European language speaking Gujarati Indians with genome-wide data from the International HapMap Project; and (2) the Dravidian language speaking Tamil Indians with genome-wide data from the Singapore Genome Variation Project.
Results
We implemented three population genetics measures to identify genomic regions that are significantly differentiated between the two Indian populations originating from the north and south of India. These measures singled out genomic regions with: (i) SNPs exhibiting significant variation in allele frequencies in the two Indian populations; and (ii) differential signals of positive natural selection as quantified by the integrated haplotype score (iHS) and cross-population extended haplotype homozygosity (XP-EHH). One of the regions that emerged spans the SLC24A5 gene that has been functionally shown to affect skin pigmentation, with a higher degree of genetic sharing between Gujarati Indians and Europeans.
Conclusions
Our finding points to a gene-flow from Europe to north India that provides an explanation for the lighter skin tones present in North Indians in comparison to South Indians.
Regional differences in IQ are estimated for 47 prefectures of Japan. IQ scores obtained from official achievement tests show a gradient from north to south. Latitudes correlate with height, IQ, and skin color at r = 0.70, 0.44, 0.47, respectively. IQ also correlates with height (0.52), skin color (0.42), income (0.51) after correction, less homicide rate (− 0.60), and less divorce (− 0.69) but not with fertility infant mortali'ty. The lower IQ in southern Japanese islands could be attributable to warmer climates with less cognitive demand for more than fifteen hundred years.
Regional differences in IQ and per capita incomes are presented for five regions of Portugal: North, North Central, Lisbon-Central, Lisbon-Suburb, and South. Regional IQs were calculated from a representative sample of 4548 Portuguese school students from 5th to 12th grades. The average IQ and average incomes are highest in Central Lisbon. The results show a positive association between IQs and average regional incomes, as it has been observed in other countries.
This article summarizes the practical and theoretical implications of 85 years of research in personnel selection. On the basis of meta-analytic findings, this article presents the validity of 19 selection procedures for predicting job performance and training performance and the validity of paired combinations of general mental ability (GMA) and the 18 other selection procedures. Overall, the 3 combinations with the highest multivariate validity and utility for job performance were GMA plus a work sample test (mean validity of .63), GMA plus an integrity test (mean validity of .65), and GMA plus a structured interview (mean validity of .63). A further advantage of the latter 2 combinations is that they can be used for both entry level selection and selection of experienced employees. The practical utility implications of these summary findings are substantial. The implications of these research findings for the development of theories of job performance are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The relationship between intelligence and socioeconomic success has been the source of numerous controversies. The present paper conducted a meta-analysis of the longitudinal studies that have investigated intelligence as a predictor of success (as measured by education, occupation, and income). In order to better evaluate the predictive power of intelligence, the paper also includes meta-analyses of parental socioeconomic status (SES) and academic performance (school grades) as predictors of success. The results demonstrate that intelligence is a powerful predictor of success but, on the whole, not an overwhelmingly better predictor than parental SES or grades. Moderator analyses showed that the relationship between intelligence and success is dependent on the age of the sample but there is little evidence of any historical trend in the relationship.
Genotypes may influence the phenotypic associations among IQ, education, and income. To investigate this hypothesis, we believe that the appropriate methodology requires estimation of genetic and environmental influences using data able to separate these influences. The National Longitudinal Survey of Youth (NLSY) is a nationally representative sample that contains genetically-informative full- and half-siblings (28–35 years old in 1992; Ns=1943 full-siblings, 129 half-siblings). A biometric genetic model was fit that estimated the shared environmental and genetic variance components of IQ, years of education, and hourly income. The total heritabilities were 0.64 for IQ, 0.68 for education, and 0.42 for income. Heritabilities due to a common genetic factor were 0.35 for IQ, 0.52 for education, and 0.12 for income. Environmental influences due to a common shared environmental factor were 0.23 for IQ, 0.18 for education, and 0.08 for income. The model predicted a correlation of 0.63 between IQ and education and 0.34 between IQ and income. Sixty-eight percent of the former and 59% of the latter was genetically mediated; the remainder was mediated by common shared environment. These findings suggest that social inequality in the United States has its origin in both genetically-based traits and in different environmental backgrounds.
We suggest that an over-arching ‘fitness factor’ (an index of general genetic quality that predicts survival and reproductive success) partially explains the observed associations between health outcomes and intelligence. As a proof of concept, we tested this idea in a sample of 3654 US Vietnam veterans aged 31–49 who completed five cognitive tests (from which we extracted a g factor), a detailed medical examination, and self-reports concerning lifestyle health risks (such as smoking and drinking). As indices of physical health, we aggregated ‘abnormality counts’ of physician-assessed neurological, morphological, and physiological abnormalities in eight categories: cranial nerves, motor nerves, peripheral sensory nerves, reflexes, head, body, skin condition, and urine tests. Since each abnormality was rare, the abnormality counts showed highly skewed, Poisson-like distributions. The correlation matrix amongst these eight abnormality counts formed only a weak positive manifold and thus yielded only a weak common factor. However, Poisson regressions showed that intelligence was a significant positive predictor of six of the eight abnormality counts, even controlling for diverse lifestyle covariates (age, obesity, combat and toxin exposure owing to service in Vietnam, and use of tobacco, alcohol, marijuana, and hard drugs). These results give preliminary support for the notion of a superordinate fitness factor above intelligence and physical health, which could be further investigated with direct genetic assessments of mutation load across individuals.
Regional differences in IQ are presented for 12 regions of Italy showing that IQs are highest in the north and lowest in the south. Regional IQs obtained in 2006 are highly correlated with average incomes at r = 0.937, and with stature, infant mortality, literacy and education. The lower IQ in southern Italy may be attributable to genetic admixture with populations from the Near East and North Africa.
To test the association between childhood IQ and mortality over the normal human lifespan.
Longitudinal cohort study.
Aberdeen. Subjects: All 2792 children in Aberdeen born in 1921 and attending school on 1 June 1932 who sat a mental ability test as part of the Scottish mental survey 1932.
Survival at 1 January 1997.
79.9% (2230) of the sample was traced. Childhood mental ability was positively related to survival to age 76 years in women (P<0.0001) and men (P<0.0001). A 15 point disadvantage in mental ability at age 11 conferred a relative risk of 0.79 of being alive 65 years later (95% confidence interval 0.75 to 0.84); a 30 point disadvantage reduced this to 0.63 (0.56 to 0.71). However, men who died during active service in the second world war had a relatively high IQ. Overcrowding in the school catchment area was weakly related to death. Controlling for this factor did not alter the association between mental ability and mortality.
Childhood mental ability is a significant factor among the variables that predict age at death.
Virtually all indicators of physical health and mental competence favor persons of higher socioeconomic status (SES). Conventional theories in the social sciences assume that the material disadvantages of lower SES are primarily responsible for these inequalities, either directly or by inducing psychosocial harm. These theories cannot explain, however, why the relation between SES and health outcomes (knowledge, behavior, morbidity, and mortality) is not only remarkably general across time, place, disease, and kind of health system but also so finely graded up the entire SES continuum. Epidemiologists have therefore posited, but not yet identified, a more general "fundamental cause" of health inequalities. This article concatenates various bodies of evidence to demonstrate that differences in general intelligence (g) may be that fundamental cause.
A series of studies have shown an association between high childhood IQ scores and reduced rates of total mortality in adulthood. Several mechanisms have been advanced to explain these relationships, including mediation via established risk factors. This study examines the association between childhood IQ and a range of established physiological and behavioural risk factors for premature mortality in adulthood. Design,
In 1962, 12,150 children took part in a school-based survey when their IQ scores were extracted from educational records. When re-surveyed forty years later (n = 7183; 63.7% response), they self-reported information on risk factors for premature mortality (smoking, heavy alcohol consumption, obesity, height, hypertension and diabetes).
In sex-adjusted analyses based on an analytical sample of 5340 (2687 women), higher childhood IQ scores were associated with a decreased prevalence of ever having smoked regularly in adulthood (OR(per SD increase in IQ) (95% CI): 0.77 (0.73 to 0.81)), heavy alcohol consumption (0.89 (0.84 to 0.94)), obesity (0.78 (0.72 to 0.83)) and overweight (0.86 (0.81 to 0.91)). Higher IQ scores were similarly related to a reduced prevalence of short stature and higher rates of smoking cessation in smokers; effects that were stronger in women (p value for interaction: < or =0.04). Adjusting for indicators of early and, particularly, later-life socioeconomic circumstances led to heavy attenuation of these gradients with statistical significance at conventional levels lost in most analyses.
The IQ-risk factor gradients reported may offer some insights into the apparent link between high pre-adult IQ and reduced mortality rates.
To examine the role of potential mediating factors in explaining the IQ-mortality relation.
A total of 4316 male former Vietnam-era US army personnel with IQ test results at entry into the service in late adolescence/early adulthood in the 1960/1970s (mean age at entry 20.4 years) participated in a telephone survey and medical examination in middle age (mean age 38.3 years) in 1985-6. They were then followed up for mortality experience for 15 years.
In age-adjusted analyses, higher IQ scores were associated with reduced rates of total mortality (hazard ratio (HR)(per SD increase in IQ) 0.71; 95% CI 0.63 to 0.81). This relation did not appear to be heavily confounded by early socioeconomic position or ethnicity. The impact of adjusting for some potentially mediating risk indices measured in middle age on the IQ-mortality relation (marital status, alcohol consumption, systolic and diastolic blood pressure, pulse rate, blood glucose, body mass index, psychiatric and somatic illness at medical examination) was negligible (<10% attenuation in risk). Controlling for others (cigarette smoking, lung function) had a modest impact (10-17%). Education (0.79; 0.69 to 0.92), occupational prestige (0.77; 0.68 to 0.88) and income (0.86; 0.75 to 0.98) yielded the greatest attenuation in the IQ-mortality gradient (21-52%); after their collective adjustment, the IQ-mortality link was effectively eliminated (0.92; 0.79 to 1.07).
In this cohort, socioeconomic position in middle age might lie on the pathway linking earlier IQ with later mortality risk but might also partly act as a surrogate for cognitive ability.
Regional differences in IQ are reported for Finland showing that average IQs are highest in the south, containing the capital city of Helsinki. It is proposed that the selective migration of those with higher IQs to Helsinki has been the major factor responsible for the higher average IQ in the south. Regional IQs are positively correlated with the percentage of the population with tertiary education, mean income, and average male and female life expectancy; and negatively with the percentage of the population with average income less than 60% of the national median, the percentage of unemployment, and the rate of infant mortality.
Jencks' (1972) classical study Inequality reported a correlation of 0.310 between IQ and income for men in the United States. The present study examines whether this result can be replicated in Britain. Data are reported for a national sample whose intelligence was obtained at the age of 8 years and whose income was obtained at the age 43 years. The correlations between IQ and income were 0.368 for men (n=1280) and 0.317 for women (n=1085).
IQs are presented for fifteen regions of Spain showing a north-south gradient with IQs highest in the north and lowest in the south. The regional differences in IQ are significantly correlated with educational attainment, per capita income, literacy, employment and life expectancy, and are associated with the percentages of Near Eastern and North African genes in the population.
Historical Understanding of the Problem Natural Selection in Preindustrial Societies The Breakdown of Natural Selection The Genetic Deterioration of Health Intelligence and Fertility Sibling Studies Intelligence and Fertility in the United States Intelligence and Fertility in Europe Resolving the Paradox of the Secular Rise of Intelligence Education and Fertility Socioeconomic Status and Fertility Socioeconomic Status Differences in Intelligence Socioeconomic Status Differences in Conscientiousness The Genetic Basis of Socioeconomic Status Differences in Conscientiousness Dysgenic Fertility for Conscientiousness Dysgenic Fertility in Economically Developing National Counterarguments and Rejoinders.
This study reports the differences in intelligence across thirty-one regions of the People's Republic of China. It was found that regional IQs were significantly associated with the percentage of Han in the population (r = .59), GDP per capita (r = .42), the percentage of those with higher education (r = 38, p<.05), and non-significantly with years of education (r = .32). The results of the multiple regression showed that both the percentage of Han in the region and the GDP per capita were significant predictors of regional IQs, accounting for 39% of the total variance.
Cognitive epidemiology shows that more intelligent individuals stay healthier and live longer, but it is not known why. The system integrity theory predicts that more intelligent individuals are more protected from diseases that are more heritable, while the evolutionary novelty theory predicts that they are more protected from diseases that are less heritable. The paper proposes a new method of testing the competing hypotheses. An analysis of two large-scale population data sets from Sweden (n = 1 million for individual data and n = 9.6 million for heritability data) shows that intelligence is more important for health when the cancer heritability is low, supporting the evolutionary novelty theory. While the present results are merely suggestive, not conclusive, the proposed method can be extended to include other diseases and causes of death.
Context:
India is considered a treasure for geneticists and evolutionary biologists due to its vast human diversity, consisting of more than 4500 anthropologically well-defined populations (castes, tribes and religious groups). Each population differs in terms of endogamy, language, culture, physical features, geographic and climatic position and genetic architecture. These factors contributed to India-specific genetic variations which may be responsible for various common diseases in India and its migratory populations. As a result, interpretations of the origins and affinities of Indian populations as well as health and disease conditions require complex and sophisticated genetic analysis. Evidence of ancient human dispersals and settlements is preserved in the genome of Indian inhabitants and this has been extensively analysed in conventional and genomic analyses.
Objective and methods:
Using genomic analyses of STRs and Alu on a set of populations, this study estimates the level and extent of genetic variation and its implications.
Results:
The results show that Indian populations have a higher level of unique genetic diversity which is structured by many social processes and geographical attributes of the country.
Conclusion:
This overview highlights the need to study the anthropological structure and evolutionary history of Indian populations while designing genomic and epigenomic investigations.
Complex Problem Solving (CPS) is considered to be a promising candidate for capturing higher order thinking skills that are emphasized in new educational curricula but are not adequately measured by traditional intelligence tests. However, little is known about its psychometric structure and its exact relation to intelligence and educational success—especially in student populations. This study is among the first to use a large and representative sample of secondary school students (N = 563) to examine different measurement models of CPS—that conceptualize the construct as either faceted or hierarchical—and their implications for the construct's validity. Results showed that no matter which way it was conceptualized, CPS was substantially related to reasoning and to different indicators of educational success. Controlling for reasoning within a joint hierarchical measurement model, however, revealed that the impressive external validity was largely attributable to the variance that CPS shares with reasoning, suggesting that CPS has only negligible incremental validity over and above traditional intelligence scales. On the basis of these results, the value of assessing CPS within the educational context is discussed.
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.
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.
Background:
In the last decade, an increasing body of empirical evidence has gathered to establish an association between higher cognitive ability in youth and later mortality, less morbidity and better health. This field of research is known as cognitive epidemiology. The causes of these associations are not understood.
Objective:
Among the possible explanations for the associations is the suggestion that they might, in part, be accounted for by general bodily 'system integrity'. That is, scoring well on cognitive ability tests might be an indicator of a more general tendency for complex systems in the body to be efficient. The construct of system integrity is critically assessed.
Method:
This viewpoint provides a critical presentation and an empirical and theoretical evaluation of the construct of system integrity as it is used in cognitive epidemiology.
Results:
A precedent of the system integrity suggestion is discovered. The empirical tests of the system integrity idea to date are critically evaluated. Other possible routes to testing system integrity are suggested. There is a critical re-evaluation of the idea and other, related concepts.
Conclusion:
The construct of system integrity is distinct from related constructs. It is still underdeveloped theoretically, and undertested empirically within cognitive epidemiology.
Data are presented to show that there are differences in mean population IQ in different regions of the British Isles. Mean population IQ is highest in London and South-East England and tends to drop with distance from this region. Mean population IQs are highly correlated with measures of intellectual achievement, per capita income, unemployment, infant mortality and urbanization. The regional differences in mean population IQ appear to be due to historical differences which are measured back to 1751 and to selective migration from the provinces into the London area.
Data are presented for the 90 Departements of France for mean population IQs, earnings, unemployment, intellectual achievement and infant mortality. Most of the variables are significantly associated. Mean population IQs are also significantly correlated with migration since 1801 and it is suggested that internal migration has been an important factor leading to contemporary differences in intelligence.
International cognitive ability and achievement comparisons stem from different research traditions. But analyses at the interindividual data level show that they share a common positive manifold. Correlations of national ability means are even higher to very high (within student assessment studies, r = .60–.98; between different student assessment studies [PISA-sum with TIMSS-sum] r = .82–.83; student assessment sum with intelligence tests, r = .85–.86). Results of factor analyses indicate a strong g-factor of differences between nations (variance explained by the first unrotated factor: 94–95%). Causes of the high correlations are seen in the similarities of tests within studies, in the similarities of the cognitive demands for tasks from different tests, and in the common developmental factors at the individual and national levels including known environmental and unknown genetic influences. Copyright © 2007 John Wiley & Sons, Ltd.
What is the relation between the cognitive competence of a national population that nation's economic prosperity? Lynn and Vanhanen [Lynn, R. & Vanhanen, T. (2002). IQ and the wealth of nations. Westport, CT: Praeger.] presented data pointing to an exceptionally strong relationship between IQ scores and Gross Domestic Product per capita (GDP/c). However weaknesses in the Lynn and Vanhanen data set greatly reduce its construct validity. We re-examine the Lynn and Vanhanen data set and find that although the correlation between the IQ scores and GDP/c is approximately the same in developed and developing nations the absolute error in prediction of GDP/c from IQ is greater in the developing than the developed nations. We then show that recently obtained contemporary educational data from the Program for International Student Assessment (PISA) provides a better predictor of national wealth than does the Lynn–Vanhanen data set. We conclude that in spite of the weaknesses several of their data points Lynn and Vanhanen's empirical conclusion was correct, but we question the simple explanation that national intelligence causes national wealth. We argue that the relationship is more complex.
Political theory has described a positive linkage between education, cognitive ability and democracy. This assumption is confirmed by positive correlations between education, cognitive ability, and positively valued political conditions (N = 183 − 130). Longitudinal studies at the country level (N = 94 − 16) allow the analysis of causal relationships. It is shown that in the second half of the 20th century, education and intelligence had a strong positive impact on democracy, rule of law and political liberty independent from wealth (GDP) and chosen country sample. One possible mediator of these relationships is the attainment of higher stages of moral judgment fostered by cognitive ability, which is necessary for the function of democratic rules in society. The other mediators for citizens as well as for leaders could be the increased competence and willingness to process and seek information necessary for political decisions due to greater cognitive ability. There are also weaker and less stable reverse effects of the rule of law and political freedom on cognitive ability.
The impetus for our study was the contention of both Lynn [Lynn, R. (1991) Race differences in intelligence: A global perspective. Mankind Quarterly, 31, 255–296] and Rushton (Rushton [Rushton, J. P. (1995). Race, evolution and behavior: A life history perspective. New Brunswick, NJ: Transaction; Rushton, J. P. (1997). Race, intelligence, and the brain: The errors and omissions of the revised edition of S.J. Gould's the mismeasurement of man. Personality and Individual Differences, 23, 169–180; Rushton, J. P. (2000). Race, evolution, and behavior. A life history perspective (3rd edition). Port Huron: Charles Darwin Research Institute] that persons in colder climates tend to have higher IQs than persons in warmer climates. We correlated mean IQ of 129 countries with per capita income, skin color, and winter and summer temperatures, conceptualizing skin color as a multigenerational reflection of climate. The highest correlations were − 0.92 (rho = − 0.91) for skin color, − 0.76 (rho = − 0.76) for mean high winter temperature, − 0.66 (rho = − 0.68) for mean low winter temperature, and 0.63 (rho = 0.74) for real gross domestic product per capita. The correlations with population of country controlled for are almost identical. Our findings provide strong support for the observation of Lynn and of Rushton that persons in colder climates tend to have higher IQs. These findings could also be viewed as congruent with, although not providing unequivocal evidence for, the contention that higher intelligence evolves in colder climates. The finding of higher IQ in Eurasians than Africans could also be viewed as congruent with the position of Diamond (1997) that knowledge and resources are transmitted more readily on the Eurasian west–east axis.
Cognitive abilities are important for the economic and non-economic success of individuals and societies. For international analyses, the collection of IQ-measures from Lynn and Vanhanen was supplemented and meliorated by data from international student assessment studies (IEA-Reading, TIMSS, PISA, PIRLS). The cognitive level of a nation is highly correlated with its educational level (r = .78, N = 173). In international comparisons, it also shows a high correlation with gross domestic product (GDP, r = .63, N = 185). However, in cross-sectional studies, the causal relationship between intelligence and national wealth is difficult to determine. In longitudinal analyses with various samples of nations, education and cognitive abilities appear to be more important as developmental factors for GDP than economic freedom. Education and intelligence are also more relevant to economic welfare than vice versa, but at the national level the influence of economic wealth on cognitive development is still substantial.
Epidemiologists contend that income inequality reduces the health and life expectancy of the whole population, but this argument does not make sense within its own evolutionary framework. Recent evolutionary psychological theory suggests that the human brain, adapted to the ancestral environment, has difficulty comprehending and dealing with entities and situations that did not exist in the ancestral environment, and that general intelligence evolved as a domain-specific adaptation to solve evolutionarily novel problems. Since most dangers to health in the contemporary society are evolutionarily novel, it follows that more intelligent individuals are better able to recognize and deal with such dangers and live longer. Consistent with the theory, and replicating an earlier study of cross-national data, income inequality has no effect on the health and longevity of the population across the American states, when the racial composition (percent black) is controlled, but the average intelligence of the population (state IQ) has a significant effect. The data presented here and in the earlier study challenge the conclusion that income inequality reduces the health of the population.
The effects of inbreeding in humans on the intelligence has been investigated in the present study of offspring of second cousin matings (F=0.0156, n=138 male, 132 female), first cousins once removed (F=0.03125, n=148 male, 138 female), first cousins (F=0.0625, n=161 male, 151 female), and unrelated (F=0, n=194 male, 182 female) among North Indian Muslims. The Weschler Intelligence Scale for Children (WISC-R)-74 was given to the children in the both groups. An overall significant (p<0.001) reduction of means has been observed in inbred series. The results of this study confirm the appreciable inbreeding depression especially among the offspring of first cousins.
Studies of middle-aged and particularly older-aged adults found that those with higher scores on tests of IQ (cognitive function) had lower rates of later mortality. Interpretation of such findings potentially is hampered by the problem of reverse causality: such somatic diseases as diabetes or hypertension, common in older adults, can decrease cognitive function. Studies that provide extended follow-up of the health experience of individuals who had their (premorbid) IQ assessed in childhood and/or early adulthood minimize this concern. The purpose of the present report is to systematically locate, evaluate, and interpret the findings of all such studies.
We systematically identified individual-level studies linking premorbid IQ with later mortality by using four approaches: search of electronic databases (MEDLINE, EMBASE, and PSYCHINFO); scrutiny of the reference sections of identified reports; search of our own files; and contact with researchers in the field. Study quality was assessed by using predefined criteria.
Nine cohort studies met the inclusion criteria. Overall, study quality was moderate. All reports showed an inverse IQ-mortality relation; i.e., higher IQ scores were associated with decreased mortality risk. The nature of this relation (i.e., dose-response or threshold) and whether it differs by sex was unclear. The IQ-mortality association did not appear to be explained by reverse causality or selection bias. Confounding by other early-life factors also did not seem to explain the association, although some studies were not well characterized in this regard. Adult socioeconomic position appeared to mediate the IQ-mortality association in some studies, but this was not a universal finding.
In all studies, higher IQ in the first two decades of life was related to lower rates of total mortality in middle to late adulthood. Some plausible mechanistic pathways exist, but further examination is required. The precise nature of the IQ-mortality relation (particularly in ethnic minorities and women) and the link between IQ and disease-specific outcomes also warrants further research.
Inequality. London: Penguin
- C Jencks
Jencks, C. (1972). Inequality. London: Penguin.
Intelligence: A unifying construct for the social sciences
- R Lynn
- T Vanhanen
Lynn, R., & Vanhanen, T. (2012). Intelligence: A unifying construct for the social sciences. London: Ulster Institute for Social Research.