In the absence of direct benefits of choice, female preferences for male traits initially spread because the preference becomes associated with high fitness genotypes. We consider a reinforcement scenario where hybrids have low fitness and a single locus controls local adaptation. In this system, the strength of selection on female preferences is constrained by the equilibrium migration load; female preferences spread to the degree that they avoid association with low reproductive value genotypes. By decomposing the invasion matrix, we can determine which types of matings and female genotypes contribute the most to selection on mating preference. We find that preferences against hybrid males are more beneficial than preferences for local adaptation both because of the information content of hybrid genotype and because of the increased likelihood of creating beneficial genetic associations. This is true regardless of the relative strengths of selection on hybrids and local adaption. However, this asymmetry is due in part to the ability of particular genetic architectures to create migration load. We show that when local adaptation has a polygenic basis, then the strength of selection on preferences for local adaptation can be as strong as selection for preferences against hybrids.