Immigrant-majority group differences in cognitive performance: Jensen effects, cultural effects, or both.

When a positive correlation occurs between g-loadedness of a cognitive test and variable X, the result is termed a "Jensen effect." Virtually all Dutch studies comparing immigrants with Dutch show that the differences in mean scores on intelligence tests are dependent on the g loading of the tests and are therefore clear Jensen effects. However, Helms-Lorenz, van de Vijver, and Poortinga [Intelligence 31 (2003) 9] challenge the overwhelming finding of Jensen effects and suggest that group differences on measures of phenotypic intelligence are more strongly caused by cultural differences than by g. We attempted to replicate Helms-Lorenz et al.'s finding of absence of Jensen effects on two large samples that took both culture-loaded and culture-reduced tests. We found proof of Jensen effects, a very large language bias effect in one specific intelligence test, and quite small cultural bias effects in the remaining intelligence tests. It appears that Helms-Lorenz et al.'s findings are an outlier among all empirical studies, which may be caused by the use of an unrepresentative set of tests. © 2003 Elsevier Science Inc. All rights reserved.