European and American WAIS IV norms: Cross-national differences in perceptual reasoning, processing speed and working memory subtest scores.

International comparisons of IQ test norms show differences between nations. In the present study, nonverbal reasoning, processing speed and working memory subtest scores of the US, German, French, Finnish, and Scandinavian (combined Swedish-Norwegian-Danish sample) WAIS IV standardization samples were compared. The European samples had higher scores on the reasoning subtests compared to the American sample, corroborating earlier studies. The Finnish and Scandinavian samples had lower processing speed and working memory scores than the American, German, and French samples. Mechanisms that may underlie the observed national IQ profiles include: (1) test-taking attitudes-in tests that require balancing speed and accuracy of performance Americans may prioritize fast performance while Europeans avoid mistakes; (2) differences between languages in digit articulation times; and (3) educational factors-the European advantage on reasoning subtests may be based on there being better educational systems in Europe as compared to the US.