One explanation to rule them all

I've commented on height genetics now & then. It seems that the quantitative genetic supposition that variation on this trait was due to the cummulative effect of numerous loci of small effect is correct. Recent research has pinpointed about ~5% of the variance. In contrast, skin color variation is mostly due to polymorphism on about 6 loci; most of the variance is due to genes of large effect. This makes specific discussion of skin color easy, but height difficult. I've been thinking about this when it comes social phenomena. Much of the verbal treatment presupposes a few large effect explanatory variables; but what if that's not correct? What if most social phenomena are contingent upon thousands of small effect predictors? How are you going to talk about this? And since we don't know the "gene" unit of social phenomena where do you even start? Of ourse quantitative social scientists focus on phenomena which do have independent variables of big effect; but most of the action might not be low hanging fruit, but rather dispersed in the canopy.