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.