A secular decline in the strength of Spearman’s g in Japan

It has been found in the United States and in Scotland that the subtests of the WISC-R and WAIS-R are more highly intercorrelated among low-intelligence groups than among high. The value of the intercorrelations is a measure of the strength of Spearman’s g, and hence Spearman’s g is apparently stronger among populations with low intelligence. Since intelligence has been increasing over time, it should follow that the strength of g has shown a corresponding decline. Evidence from the standardization samples of the WISC and WISC-R in Japan shows that this is the case.     

The factorial similarity of the WISC-R performance Scale in deaf and hearing samples

Wechsler Intelligence Scale for Children—Revised (WISC-R) Performance Scale metrics and subtest factor loadings, derived separately from deaf (N = 1228) and hearing (N = 2200) samples, are practically identical. Small mean differences are probably attributable to the higher incidence of brain damage among deaf children. In addition to demonstrating the absence of construct bias in WISC-R Performance IQ (PIQ) measurement for deaf children, the results contradict theories which propose linguistic bias as the cause of the white-black difference in Performance IQ. Spearman's hypothesis that white-black mental test differences are primarily a difference in g received significant support. The results indicate that cognition, as measured by PIQ, is virtually independent of language acquisition.     

Intelligence, Personality and Performance on Case Studies

Standard individual difference antecedents of two stages in the case study assessment process were determined in a sample of 305 students. We found that antecedents to the problem identification and analysis stages of case assessment differed. Specifically, we tested intelligence and personality traits as the predictors and found that openness to experience was significantly positively correlated with an individual’s score on problem identification and that general intelligence was significantly positively correlated with an individual’s score on analysis. Additionally, there was a positive relationship between extraversion and agreeableness and an individual’s analysis score and a significant negative relationship between conscientiousness and an individual’s score on problem identification. Moreover, intelligence and conscientiousness interacted to predict an individual’s analysis score with high conscientiousness partially compensating for an individual’s relatively low intelligence.     

The structure of Japanese abilities: An analysis in terms of the hierarchical model of intelligence

The structure of Japanese abilities is analyzed in terms of the Burt-Vernon hierarchical model of intelligence. The data are derived from the Japanese standardization of theWechsler Intelligence Scale for Children-Revised. It is found that Japanese children are marginally but significantly superior to white American children on Spearman’sg. Japanese children are inferior on the group verbal factor but superior on the group perceptual factor. On the primary abilities, Japanese children are inferior on verbal comprehension and perceptual speed and superior on memory span, 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.     

Rushton’s contributions to the study of mental ability

This essay describes Rushton’s contribution to examining the nexus of intelligence, race, and genetics, specifically what I termed “Spearman’s hypothesis”. It states that Black–White differences are “most marked in just those [tests] which are known to be saturated with g”. I (Jensen) had confirmed this hypothesis using large data sets in the 1970s and 1980s and also found that Black–White differences were most marked on the more heritable rather than the more cultural subtests. Rushton confirmed and extended these findings in many highly innovative ways and demonstrated Spearman’s hypothesis applied among samples of Gypsy Roma in Serbia, and East Asian, European, South Asian, Colored and Black samples in South Africa. He has not only documented group differences in brain size, intelligence, life span, family structure, infant mortality, developmental precocity, personality, and temperament, and rates of two egg twinning, and crime among East Asians, Europeans, and Africans, but also provided a life history theory that explains them.     

Raising argument strength using negative evidence: a constraint on models of induction

Both intuitively, and according to similarity-based theories of induction, relevant evidence raises argument strength when it is positive and lowers it when it is negative. In three experiments, we tested the hypothesis that argument strength can actually increase when negative evidence is introduced. Two kinds of argument were compared through forced choice or sequential evaluation: single positive arguments (e.g., “Shostakovich’s music causes alpha waves in the brain; therefore, Bach’s music causes alpha waves in the brain”) and double mixed arguments (e.g., “Shostakovich’s music causes alpha waves in the brain, X’s music DOES NOT; therefore, Bach’s music causes alpha waves in the brain”). Negative evidence in the second premise lowered credence when it applied to an item X from the same subcategory (e.g., Haydn) and raised it when it applied to a different subcategory (e.g., AC/DC). The results constitute a new constraint on models of induction.     

II. The comparability of the WISC-R and WAIS among 16-year-old EMR children

Thirty 16-year-old EMR children were administered the WAIS and WISC-R in counterbalance order to determine the comparability of the two assessment instruments. The WAIS was found to yield significantly higher Verbal, Performance, and Full Scale IQ scores. The comparisons of corresponding subtests indicate that all WAIS subtests were significantly higher than the WISC-R except Picture Completion. Correlations between corresponding WAIS and WISC-R IQ scales and subtests, however, were significant. The results suggest differences between the two instruments among children of subnormal intelligence, thus presenting the possibility that a child may be differentially classified based on the selection of the intelligence test.     

The WISC-R factoral validity for minority groups and Spearman's hypothesis

The factoral structure of the WISC-R for groups of Anglo, Black, and Mexican-American children was compared and found to be highly similar across groups. The tests appear to be measuring the same abilities in all three groups. The order of subtest difficulty was not significantly correlated with the subtest g loadings for the Black children but was for the Mexican-Americans. These results provide support for Spearman's hypothesis with Mexican-American children.     

Teachers facing school failure: the social valorization of effort in the school context

This paper describes two studies concerning teachers’ classroom interventions facing school failure. The role of two main variables is investigated: the lack of effort as a cause of failure students are held responsible for by teachers, and teacher’s social representations of intelligence. The first study (Study 1) explored the impact of “lack of effort” causal attribution for student’s failure on the intervention strategies adopted by 122 high school teachers. Study 2 analyzed the impact of social representations of intelligence, held by 202 high school teachers, on “lack of effort” causal inference and on behavioral interventions. Results highlight that teachers mostly choose more severe educational interventions with retributive purpose when failure is ascribable to an absence of effort expenditure by the student. Moreover, the findings support the role of teachers’ social representations of intelligence in failure explanations and in educational practices, showing that “lack of effort” attribution and practices with retributive purpose are predicted by the social representation of intelligence “as a gift”. Results are analyzed and discussed by considering the effort as a normative parameter of the school environment. This research was supported financially in part by MURST “University funds, 2004 (Ex 40%)”. Portions of these results were presented at the 8th International Conference on Social Representations, Rome.     

Exposure to Parental Cigarette Smoking and Child Problem Behaviors: A Longitudinal Study

This study examined exposure to environmental tobacco smoke (ETS), a major public health problem. ETS has been found to be associated with an increased risk of adverse health effects in children. This study utilizes data from a community-based, longitudinal investigation examining the relation between children’s exposure to ETS and later internalizing symptoms and externalizing behaviors. Interviews were administered to a representative community sample of participants from two New York State counties in 1983, with subsequent interviews in 1985–1986, 1992, 1997, and 2002–2003 (when the participants’ mean age was 32). Data was collected on various personality and behavioral characteristics of the participants, and on internalizing symptoms and externalizing behaviors demonstrated by their children. Results indicated that children’s exposure to ETS was associated with an increased risk for both internalizing symptoms and externalizing behaviors. This relationship was maintained despite control on a number of parental psychosocial risk factors (e.g., demographic variables, personality and behavioral attributes) that have been found to be associated with both parental cigarette smoking and behavior problems among children. These data, which indicate an association between exposure to ETS and internalizing symptoms and externalizing behaviors among children, support public health policies to further restrict children’s exposure to ETS.