It has been suggested that the "g" loading of mental tests have been found to correlate with heritability, but both the empirical data and statistical methodology bearing on this question are matters of active controversy. Several studies suggest that tests with larger "g" loadings are more affected by inbreeding depression lowering test scores. There is also evidence that tests with larger "g" loadings are associated with larger positive heterotic effects on test scores, which has been suggested to indicate the presence of genetic dominance effects for "g".