Several different analyses were used to test the hypothesis that test-taking motivation, perceived test fairness, and actual test performance are correlated only because they share a common antecedent. First, hierarchical regressions reveal that initial test performance has a unique influence on non-ability factors even after controlling for test-takers' initial standing on those factors. Second, the variance underlying performance was partitioned into "g" and non-"g" components. Partial correlations show that the non-ability factors are essentially unrelated to performance after controlling for variance in "g." Third, a correlated vectors analysis showed that the degree of "g"-saturation of the cognitive ability scales was significantly correlated with the magnitude of the correlations between performance on the scale and the non-ability variables. Lastly, only the "g"-variance underlying initial test performance predicted changes in motivation and fairness perceptions across repeated testing, but initial motivation and fairness perceptions did not influence changes in performance. It is concluded that, as suggested by the self-serving bias hypothesis, the relations between non-ability factors and test performance are largely due to a common antecedent, namely "g."