Investigating Group Differences on Cognitive Tests Using Spearman's Hypothesis: An Evaluation of Jensen's Method

Area of Science:

• Psychometrics
• Cognitive Psychology
• Quantitative Psychology

Background:

• Jensen's method proposes a factor analysis approach to investigate group differences in cognitive test performance.
• This method relies on identifying a general intelligence factor (g) and assessing its loadings across groups.
• A key component involves testing Spearman's Hypothesis, which posits that group differences in g explain observed score differences.

Purpose of the Study:

• To investigate the validity of inferences derived from Jensen's method for group differences in cognitive abilities.
• To compare the robustness of Jensen's method against multi-group confirmatory factor analysis (MCFA) under assumption violations.
• To evaluate the sensitivity of Jensen's method to violations concerning the existence of 'g' and Spearman's Hypothesis.

Main Methods:

• Exploratory factor analysis to extract a general intelligence factor (g).
• Assessment of factor loading similarity across groups to ensure construct measurement invariance.
• Correlation analysis between general intelligence factor loadings and group mean differences to test Spearman's Hypothesis.
• Construction of population covariance matrices with introduced violations of 'g' and Spearman's Hypothesis for comparative analysis.

Main Results:

• Jensen's method demonstrated significant insensitivity to violations of its underlying assumptions regarding the existence of 'g' and Spearman's Hypothesis.
• This lack of specificity was consistently observed across all introduced violation types.
• Multi-group confirmatory factor analysis (MCFA) proved to be substantially more valid and reliable for inferring group differences in general intelligence.

Conclusions:

• Jensen's method is not a sufficiently specific or valid tool for investigating group differences in cognitive abilities due to its insensitivity to assumption violations.
• Multi-group confirmatory factor analysis (MCFA) is a superior methodology for robustly assessing group differences in general intelligence (g).
• Researchers should favor MCFA over Jensen's method for more accurate and reliable psychometric analyses of group differences.