This study examined the relationship between culture and cognitive abilities by comparing WAIS-IV subtests, index scores, and Full-Scale Intelligence Quotient (FSIQ) scores across various age groups in the Taiwanese and U.S. populations. The Taiwanese and U.S. versions of WAIS-IV are comprehensively compared, examining subtest items, psychometrics, and sample characteristics. Scaled scores are compared by extracting raw scores with a scaled score of 10 from each subtest scale in the Taiwanese version and applying U.S. age norms to acquire U.S. scaled scores. Despite the mean FSIQ score closely aligning with the U.S. sample, notable discrepancies are evident in the Taiwanese Verbal Comprehension Index (VCI) score, potentially influenced by cultural fairness of the tests. Significant variations are observed among age cohorts in the Taiwanese sample, with younger individuals excelling in Processing Speed Index, Working Memory Index, Perceptual Reasoning Index, and FSIQ, while maintaining comparable VCI scores to their U.S. counterparts. Conversely, older cohorts demonstrate lower performance across various domains, except for visuospatial reasoning and organizational skills, compared to their U.S. counterparts. These subtest variations robustly correlate with educational disparities between the Taiwanese and U.S. samples. Despite the similarity in factor structures between the Taiwanese and U.S. versions of WAIS-IV, this study reveals cultural bias in both verbal and non-verbal subtests. The study highlights the intricate interplay among cognitive processing styles, cultural influences, and educational factors contributing to performance disparities.