Lynn (2010) suggests that differences in average intelligence explain many of the differences observed across the Italian regions. This paper puts forward a methodological critique to his study, coupling it with an empirical test showing that Lynn's analysis is not sufficiently robust to support its conclusions. (Contains 2 tables.)

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…

Working with data from the PISA study (OECD, 2007), Lynn (2010) has argued that individuals from South Italy average an IQ approximately 10 points lower than individuals from North Italy, and has gone on to put forward a series of conclusions on the relationship between average IQ, latitude, average stature, income, etc. The present paper…

This paper examines the distribution of national IQ in geographical space. When the heritability of IQ and its dependence on eco-social factors are considered from a global perspective, they suggest that the IQs of neighboring countries should be similar. Using previously published IQ data for 113 nations (Lynn, R., & Vanhanen, T., (2006). IQ and…

Responds to "Birth Order and Intelligence: Further Tests of the Confluence Model" by Robert D. Retherford and William H. Sewell. Reviews their arguments and suggests that their analyses of the Wisconsin Longitudinal Study data support rather than contradict the model. (CJS)

This research studied the interchangeability of individually administered and group administered cognitive tests. Seventy undergraduate students took the Hebrew version of the WAIS-R (Wechsler Adult Intelligence Scale-Revised), and their IQs were measured. They also took the IPET (Israeli Psychometric Entrance Test) and their IPET scores were…

Extensive data on twins, nontwin siblings, siblings separated by adoption, and parent-child similarity indicate that the heritability of intelligence is closer to .50 than to .70. Differences could be due to environmental or genetic changes in the population, or to methodology. (Author/CP)

Confluence theory was developed to explain the negative effects of birth order on intelligence. Using aggregate, between-family, within-family, and paired-sibling data from the Wisconsin Longitudinal Study, tests the mathematical form of confluence theory and finds no support for it. Suggests that statistical methods used to fit the model to the…

It is assumed that students with EBD who have more severe deficits in academic, behavior, and/or social domains are placed in more restrictive settings. However, this assumption has not been empirically tested. This study compared students educated in self-contained classrooms to students educated in a self-contained school to determine if the…

Content of school problems as posed by high school students, quality with which questions were formulated, and the relationship of content and quality to students' intellectual characteristics were investigated. Results reveal problem content most involved affectivity of teachers; problem formulation quality was egocentric; and content and quality…

Changing ideas on intelligence testing and the heritability of intelligence are followed through a fifty-year period. Common criticisms of intelligence tests are examined, but it is concluded that intellectual tests will continue to be of value in diagnosing strengths and weaknesses, particularly of exceptional children. (Editor)

The author refutes Humphrey's test of the Spearman hypothesis. A fair test requires that Black and White samples not be selected on any g-correlated variable, including socioeconomic status. Humphrey's factor analysis on test-score means of demographic groups, rather than on individuals, inflates g loadings and biases results. (LMO)

This author reviews published data and presents new data relevant to the Spearman hypothesis concerning racial differences on cognitive tests. He concludes that across-the-board difference between SES groups occurs primarily on the general factor, and that there are major determinants of race differences independent of the general factor.…

The author responds to criticisms made by Jensen pertaining to tests of the Spearman hypothesis. The near-zero correlation between Blacks and low socio-economic status Whites is neither an artifact of methodology nor a sampling fluke. Low and high SES White differences are highly correlated with general factor loadings. (LMO)