g as a consequence of shared genes

Abstract

This article argues that g can arise from the effect of shared genes influencing cognitive test performance. Further, the puzzling effect that intercorrelations between cognitive tests are higher at lower ability levels can be accounted for by incorporating the concept of deleterious mutation load. Population genetics holds that one of the determinants of retained genetic variation is deleterious mutation load, and as mutations increase genetic variation, the effect is to yield intercorrelation magnitudes that are inversely correlated to performance. A simple mathematical demonstration of how this occurs is provided. This argument predicts the need for a profound shift of tactics in the search for biological bases of g. © 2001 Elsevier Science Inc. All rights reserved.