A number of researchers have suggested that the proportion of variation accounted for by "g" may not be uniform across all subgroups within a population. Spearman's law of diminishing returns (SLODR), also termed the "cognitive ability differentiation hypothesis", predicts that the positive correlations among different cognitive abilities are weaker among more intelligent subgroups of individuals. More specifically, (SLODR) predicts that the "g" factor will account for a smaller proportion of individual differences in cognitive tests scores at higher scores on the "g" factor.