IQ in Japan and the United States shows a growing disparity

Japanese Performance Profile on the WAIS-IV and Purported Cultural Influences

OBJECTIVE

The present exploratory study aimed to examine the potential impact of culture on cognitive skills and intelligence by comparing the Japanese Wechsler Adult Intelligence Scale-IV (WAIS-IV) (JW) subtests, IQs, and index scores to those of the U.S. WAIS-IV (USW).

METHOD

JW raw scores corresponding to a scaled score of 10 for each subtest were scored with USW norms. Subtest, index, and IQ scores were then calculated for each age range. The impact of education on scores was evaluated through ratio of educational attainment for each cohort of the Japanese and US samples. Japanese and US data were compared using one-sample t-tests. Correlations between subtest, index, and IQ scores and education were calculated.

RESULTS

The USW sample performed higher than the JW sample on verbal comprehension subtests, while the JW sample demonstrated stronger performances in processing speed and perceptual reasoning subtests. However, all scores with the exception of Block Design, Matrix Reasoning, and Figure Weights were significantly associated with differential educational attainment between the two countries. Educational differences were linearly associated with age with the higher educational attainment for younger Japanese age groups and higher attainment for the older US cohorts.

CONCLUSIONS

The present study demonstrates cognitive differences between Japan and the USA. Performance on the WAIS-IV subtest and composite measures are highly correlated with education. Cultural factors impacting the cognitive profile of the Japanese sample such as differences in worldview, customs, educational systems, and writing system, were proposed. Clinical neuropsychologists should take these aspects into account when administering and interpreting test results.

Why is one study technique superior to another?

Reviewers on manuscripts or grant proposals often react positively if authors use in-favor study techniques and negatively if authors use not-in-favor study techniques. A tacit assumption is that the in-favor technique is superior to alternate techniques. However, study techniques for theory testing depend on auxiliary assumptions that connect nonobservational terms in theories with observational terms in empirical hypotheses. Therefore, the extent to which a technique is useful depends on the theory and empirical hypothesis under investigation. A technique might be useful from one theoretical perspective and not useful from another theoretical perspective. Or a technique might successfully connect to one empirical hypothesis but not another. The present work threshes out some of the relevant philosophical issues.

Changes in the Intelligence Levels and Structure in Russia: An ANOVA Method Based on Discretization and Grouping of Factors

In the present paper, we investigate how the general intelligence quotient (IQ) and its subtests changed for students from Russian University from 1991 to 2013. This study of the effect of such factors as gender, department, and year on the IQ response is carried out using the ANOVA model. Given the unevenness of the initial sample by years and departments, and consequently, heterogeneity of variances when divided by the original natural categories, we decided to aggregate the values of explanatory variables to build an adequate model. The paper proposes and investigates an algorithm for joint discretization and grouping, which uses the procedure of partial screening of solutions. It is an intermediate option between the greedy algorithm and exhaustive search. As a goodness function (an optimality criterion), we investigate 26 intermediate options between the AIC and BIC criteria. The BIC turned out to be the most informative and the most acceptable criterion for interpretation, which penalizes the complexity of the model, due to some decrease in accuracy. The resulting partition of the explanatory variables values into categories is used to interpret the modeling results and to arrive at the final conclusions of the data analysis. As a result, it is revealed that the observed features of the IQ dynamics are caused by changes in the education system and the socio-economic status of the family that occurred in Russia during the period of restructuring the society and intensive development of information technologies.

Reflections on Sixty-Eight Years of Research on Race and Intelligence

I first encountered the question of race and intelligence sixty-eight years ago[...]

The Intelligence of Biracial Children of U.S. Servicemen in Northeast Asia: Results from Japan

The IQ averages of biracial children have long been of interest to intelligence researchers for clarifying the causes of group differences in intelligence. We carried out a search for IQ test results of biracial children fathered by U.S. servicemen after World War 2 and indigenous Asian women in northeast Asian countries (Japan, Korea, China). We were able to locate a report from Japan from a foster home (n = 28–48 biracial children across tests). Results showed that there was only a minuscule IQ gap (<1 IQ) between children of Black–Japanese and White–Japanese parents. However, interpretation of the results is difficult owing to the very small sample size, the non-representative sample, and unknown patterns of assortative mating. We suggest possible avenues for future research.

Childhood intelligence and early tooth wear patterns

OBJECTIVE

The aim of this study is to explore the relationships between early dental wear patterns and preschool IQ (Intelligence Quotient, by Stanford-Binet) of the child to illuminate the historic relationship of mental queries and bruxism.

METHODS

The dental study participants were 864 Euro-American preschool and school children whose IQs were tested for school maturity purposes at the age of 4 years, followed by dental data in a cross-sectional manner at the mean age of 7.8 years. Worn dentitions were classified as "symmetric" or "right-" and "left-sided," based on the faceting of the teeth.

RESULTS

In general, the relationships of tooth wear and intelligence were scarce, reflecting social background factors. Statistically significant results between asymmetric wear and gender groups suggest that direction of jaw function has a role in the regulation of processes responsible for individual mental performance in childhood.

DISCUSSION

Increased left-side tooth wear and early advantage in the intelligence test in girls is intriguing due to the fact that they reach maturity earlier than boys in verbal articulation, controlled in most cases by the limited area on the left side of the brain.

Further Evidence on the Cognitive Abilities of the Japanese: Data from the WPPSI

The structure of abilities of Japanese children is analysed in terms of the Burt-Vernon hierarchical model of intelligence. The data are derived from the Japanese standardisation of the Wechsler Preschool and Primary Scale for Intelligence. It is found that Japanese children do not differ significantly from white American children on Spearman's g, are significantly inferior on the group verbal factor and superior on the group perceptual factor. On the primary abilities, Japanese children are inferior on verbal comprehension, not significantly different on perceptual speed, and superior on number and spatial ability. It is suggested-that this pattern of Japanese cognitive strengths and weaknesses helps to clarify a number of conflicting findings on Japanese intelligence.

Sequential-Simultaneous Analysis of Japanese Children's Performance on the Japanese McCarthy Scales

This study explored the hypothesis that Japanese children perform significantly better on simultaneous processing than on sequential processing. The K-ABC served as the criterion of the two types of mental processing. Regression equations to predict Sequential and Simultaneous processing from McCarthy performance were derived from three validity studies of the K-ABC in which 123 American children were tested on both the McCarthy Scales and the K-ABC and were applied to Lynn's analysis of Japanese McCarthy standardization data. Results of these analyses supported the hypothesis that Japanese children show a preference for simultaneous processing across virtually the entire 2 1/2- to 8 1/2-yr. age range.

Sex and Culture Differences in Perceptions of Estimated Multiple Intelligence for Self and Family

In all, 212 British and 154 Iranian students estimated their own, their parents’, and their siblings’scores on the Gardner (1983) seven multiple intelligences. Men tended to rate their own mathematical and spatial intelligence higher than did women. Iranian students thought they themselves had lower mathematical but higher spatial, musical, and intrapersonal intelligence compared with British students The Iranians rated their fathers’ mathematical and spatial IQs lower but their interpersonal and intrapersonal IQs higher than did British students. The Iranians rated their mothers’ IQs significantly lower than did the British on six of the seven scales. Results for siblings showed far fewer gender and interaction effects but many effects of culture, particularly for first brothers. Iranians rated the intelligence of their first brothers higher than did the British on six of the seven scales. Iranians tended to be more in favor of tests and more willing to acknowledge race and gender differences.

Japanese and American Children's Styles of Processing Figural Matrices

This investigation examined Japanese and American children's styles of processing computerized geometric matrices with a true/false and 1-3 elements and 0-2 transformations. Effectiveness of training in visual animation/construction or in verbal labeling was also considered. Prior to training, the 209 Japanese and American 7-, 10-, and 13-year-olds completed the Raven's Progressive Matrices and tests of perceptual reasoning and spatial relations. No outstanding differences were apparent. However, on the test of 108 figural matrices, speed/accuracy trade-off decisions differed for the two cultures. In contrast to American children, Japanese children's error decrease was accompanied by relatively little latency increase between the ages of 7and 10. This finding is attributed to Japanese children's expeditious style of considering task-related information. Moreover, this Japanese style appears to temper traditional gender differences in effectiveness of visual versus verbal training and in encoding spatial rotations.

Performance of Asian and White Children on the K-ABC: Understanding Information Processing Differences

Eighty-two children living in Taipei, Taiwan were tested with the K-ABC and several other instruments. Children were classified according to ethnic group (Asian or White) and whether they had lived in the United States. Data analyses indicate no significant differences based on the child's sex, language of the test administration, or ethnicity of the examiner. Children who had lived in the United States performed significantly higher on the achievement scale, but there were no differences on the mental processing scales. However, Asian children scored significantly higher than White children on the sequential processing scale of the K-ABC, a difference caused primarily by superior information processing of recalling numbers. Findings are discussed in terms of ethnic, environmental, cultural, and linguistic factors.

Comparisons of Children's Cognitive Representation of Number: China, France, Japan, Korea, Sweden, and the United States

Cross-national comparisons of mathematics achievement have shown differences in favour of Asian students. This study examined the idea that the superior mathematics performance of students from Japan, Korea, and China may be due, in part, to differences in cognitive representation of number that is affected by numerical language characteristics differentiating Asian and non-Asian language groups. First-graders from the People's Republic of China, Japan, Korea, France, Sweden, and the United States were asked to construct various numbers using Base 10 blocks. Chinese, Japanese, and Korean children showed a preference for using a construction of tens and ones to show numbers; place value appeared to be clearly represented in those constructions. French, Swedish, and US children, in contrast, showed a preference for using a collection of units, suggesting that they represent number as a grouping of counted objects. More Asianlanguage speakers than non-Asian-language speakers were also able to make two correct constructions for each number, which suggests greater flexibility of mental number manipulation. Thus, the unique characteristics of the Asian number language system may facilitate the teaching and learning of mathematics, especially computation, for speakers of those languages.

The Intelligence of Chinese Children in Hong Kong

In this study the Culture Fair Test was administered to a sample of 9-year-old Clhinese children in Hong Kong. The sample was matched for socioeconomic status (SES) to the Hong Kong population. The mean IQ of the sample was 113. This figure needs adjustment for the time interval between the two test standardizations and for comparison with American white children. The effect of these adjustments is to reduce the mean IQ of the Hong Kong children to 104.5.

Future Cognitive Ability: US IQ Prediction until 2060 Based on NAEP

The US National Assessment of Educational Progress (NAEP) measures cognitive competences in reading and mathematics of US students (last 2012 survey N = 50,000). The long-term development based on results from 1971 to 2012 allows a prediction of future cognitive trends. For predicting US averages also demographic trends have to be considered. The largest groups' (White) average of 1978/80 was set at M = 100 and SD = 15 and was used as a benchmark. Based on two past NAEP development periods for 17-year-old students, 1978/80 to 2012 (more optimistic) and 1992 to 2012 (more pessimistic), and demographic projections from the US Census Bureau, cognitive trends until 2060 for the entire age cohort and ethnic groups were estimated. Estimated population averages for 2060 are 103 (optimistic) or 102 (pessimistic). The average rise per decade is dec = 0.76 or 0.45 IQ points. White-Black and White-Hispanic gaps are declining by half, Asian-White gaps treble. The catch-up of minorities (their faster ability growth) contributes around 2 IQ to the general rise of 3 IQ; however, their larger demographic increase reduces the general rise at about the similar amount (-1.4 IQ). Because minorities with faster ability growth also rise in their population proportion the interactive term is positive (around 1 IQ). Consequences for economic and societal development are discussed.

Intelligence and childlessness

Demographers debate why people have children in advanced industrial societies where children are net economic costs. From an evolutionary perspective, however, the important question is why some individuals choose not to have children. Recent theoretical developments in evolutionary psychology suggest that more intelligent individuals may be more likely to prefer to remain childless than less intelligent individuals. Analyses of the National Child Development Study show that more intelligent men and women express preference to remain childless early in their reproductive careers, but only more intelligent women (not more intelligent men) are more likely to remain childless by the end of their reproductive careers. Controlling for education and earnings does not at all attenuate the association between childhood general intelligence and lifetime childlessness among women. One-standard-deviation increase in childhood general intelligence (15 IQ points) decreases women's odds of parenthood by 21-25%. Because women have a greater impact on the average intelligence of future generations, the dysgenic fertility among women is predicted to lead to a decline in the average intelligence of the population in advanced industrial nations.

Secular IQ Increases by Epigenesis? The Hypothesis of Cognitive Genotype Optimization

The short timescale of massive secular IQ gains (“Flynn Effect”) is inconsistent with positive selection of a recent gene mutation, but other genetic mechanisms are possible. Principles of evolutionary psychology, combined with secular trends, suggest an epigenetic explanation: the Cognitive Genome Optimization Hypothesis. Per life-history theory, favorable secular trends may change the phenotypic expression of the genotype which controls the neurophysiology of problem solving. The hypothesis posits two intermediate steps between reliable nutrition (the starting point) and higher IQs (ending point): (1) Earlier cognitive maturation and (2) further calibration of cognitive function by reliable social resources (cultural complexity, mandatory education). Unlike earlier generations, more resources can be deployed to cognitive maturation than to physical survival, and more time is available to calibrate cognitive processing into the upper end of the trait value range for intelligence. The secular trend of earlier puberty timing is critical: data show an association between puberty and higher IQ.

Factor structure and sex differences on the Wechsler Preschool and Primary Scale of Intelligence in China, Japan and United States

This study presents data on the factor structure of the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) and sex and cultural differences in WPPSI test scores among 5- and 6-year-olds from China, Japan, and the United States. Results show the presence of a verbal and nonverbal factor structure across all three countries. Sex differences on the 10 subtests were generally consistent, with a male advantage on a subtest of spatial abilities (Mazes). Males in the Chinese sample obtained significantly higher Full Scale IQ scores than females and had lower variability in their test scores. These observations were not present in the Japan and United States samples. Mean Full Scale IQ score in the Chinese sample was 104.1, representing a 4-point increase from 1988 to 2004.

Social versus reproductive success: The central theoretical problem of human sociobiology

The fundamental postulate of sociobiology is that individuals exploit favorable environments to increase their genetic representation in the next generation. The data on fertility differentials among contemporary humans are not cotvietent with this postulate. Given the importance ofHomo sapiensas an animal species in the natural world today, these data constitute particularly challenging and interesting problem for both human sociobiology and sociobiology as a whole.

The first part of this paper reviews the evidence showing an inverse relationship between reproductive fitness and “endowment” (i.e. wealth, success, and measured aptitudes) in contemporary, urbanized societies. It is shown that a positive relationship is observed only for those cohorts who bore their children during a unique period of rising fertility, 1935–1960, and that these cohorts are most often cited by sociobiologists as supporting the central postulate of sociobiology. Cohorts preceding and following these show the characteristic inverse relationship between endowment and fertility. The second section reviews the existing so-ciobiological models of this inverse relationship, namely, those of Barkow, Burley, and Irons, as well as more informal responses among sociobiologists to the persistent violation of sociobiology's central postulate, such as those of Alexander and Dawkins. The third section asks whether the goals of sociobiology, given the violation of its fundamental postulate by contemporary human societies, might not be better thought of as applied rather than descriptive, with respect to these societies. A proper answer to this question begins with the measurement of the pace and direction of natural selection within modern human populations, as compared to other sources of change. The vast preponderance of the shifts in human trait distributions, including the IQ distribution, appears to be due to environmental rather than genetic change. However, there remains the question of just how elastic these distributions are in the absence of reinforcing genetic change.