G and non-g influences on GPA for Hispanics and Whites: a structural equation modeling (SEM) approach to Spearman's Law of Diminishing Returns (SLDOR)
Spearman's Law of Diminishing Returns (SLODR) (Spearman, 1927) assumes that the predictive validity of general intelligence (g) should be greater for lower ability groups. SLODR also assumes that the predictive validity of non-g factors (i.e., factors weakly related or unrelated to g) should be greater for higher ability groups. While prior SLODR research has examined Black-White differences (Jensen, 1998), the current study examines Hispanic-White differences. The relationship between g and non-g factors can also be discussed under the compensatory hypothesis (Chamarro-Premuzic & Furnham, 2008), which implies that lower ability can be overcome by being more conscientious. Hypothesis testing in the current study examined whether the non- g factors of conscientiousness and grit (Duckworth et al., 2007) mediated the relationship between g and college GPA in Hispanics and Whites. Through the use of multigroup confirmatory factor analyses (CFAs), relationships among g (estimated by the SAT subtests and the Wonderlic), grit, conscientiousness, and GPA were examined in Hispanics and Whites. Overall, g and conscientiousness positively predicted GPA in the full sample, although grit did not. The multigroup CFAs revealed that the non-g factors (grit and conscientiousness) did not mediate the g to GPA relationship. Ethnicity did not act as a moderating influence on any of the paths in the multigroup CFA. The results contradicted SLODR, but did lend some support to the compensatory hypothesis. This study helps to identify factors other than g that predict success in academic environments.